Nighaṇṭu literature is a recognised branch of Āyurvedic writing in which the synonyms, properties and uses of medicinal substances are arranged in groups called Varga for ready reference by the physician. The Rāja Nighaṇṭu, also known as Abhidhāna Cūḍāmaṇi, was composed by Narahari Paṇḍita, son of Īśvarasūri, who is stated to have belonged to Kashmir [1]. Its date is unsettled, and estimates in the literature range from the twelfth to the early fifteenth century [1,2]. The text has twenty-three Varga, and the editor states that its early Varga follow the Amarakośa while presenting new matter [1]. Most Varga of the Rāja Nighaṇṭu group drugs and dietary articles under a common heading. Four are different. Dharaṇyādi (second), Manuṣyādi (eighteenth), Rogādi (twentieth) and Sattvādi (twenty-first) are not collections of drug monographs and are called here conceptual (context-setting) Varga. Their principal content is the setting in which a drug is collected, the person and disease for which it is used, and the time and measure of its use. The chapters on water, milk, flesh and minerals remain drug-oriented, and the final Ekārtha-Anekārtha Varga is a lexicon of word meanings, so these were not selected. The Manuṣyādi material appears to follow the human-classification chapter of general Sanskrit lexica, and rule-type content on drug collection and taste also occurs in the Saṃhitā literature, so the originality of these chapters is not assumed. Whether other Nighaṇṭu arranged by drug groups, such as the Dhanvantari, Madanapāla, Kaiyadeva and Bhāvaprakāśa Nighaṇṭu, contain comparable chapters was not surveyed, and no claim of uniqueness is made. The four chapters bear on problems that present-day Āyurvedic practice still faces. The botanical identity of plants named in classical sources is often disputed [3,4]. Standard terminologies and morbidity codes have been developed so that traditional diagnoses can be recorded and coded alongside biomedical ones [5-7]. Doses depend on units of weight, and the classical definitions of these units differ between sources (Section 4.4). Wild collection of medicinal plants is under pressure, and conservation literature reports that 50,000 to 80,000 flowering plant species are used medicinally, of which about 15,000 are threatened [8]. Climate change adds further risk to the supply and quality of medicinal plants [9]. The Rāja Nighaṇṭu is mostly consulted for its drug monographs, and the studies of classical plant identity cited above deal with individual drug names [3,4]. No verse-level description was found of the four conceptual chapters that relate their rules, vocabulary and units to present-day standardisation and terminology, although no systematic literature search was made for this purpose. The research question is therefore: what do these four Varga state at verse level, and which of those statements correspond, and how closely, to contemporary guidance on raw-drug collection and quality, terminology, pharmaceutical measures and sustainable use? The aims are to describe the content at verse level, to relate rule-type and vocabulary content to earlier Sanskrit sources at chapter level, and to grade each concept by the closeness of its correspondence to a contemporary standard, without claiming the validity of either system.

2.1 Design and ethics The study is a descriptive textual analysis with a qualitative appraisal of contemporary parallels. It rests on published classical and scientific literature and involved no human participant, animal subject or clinical data, so ethical clearance was not required. Verse 45 of Dharaṇyādi Varga attaches a supernatural penalty to a transgression. It is treated as cultural and ethical content, without endorsement of astrological causation. 2.2 Source text and citation convention The text was taken from the first edition (1982) of the Rāja Nighaṇṭu with the Dravyaguṇaprakāśikā Hindi commentary of Indra Dev Tripathi, with an introduction by Viśvanātha Dvivedī, published at Varanasi as Krishnadas Āyurveda Series 5 [1]. Verse numbers and the positions of the Varga follow this text. The Sanskrit verses were read directly, and the commentary was used for interpretation and is named wherever it is relied upon. Verses are cited by Varga name and printed verse number. The closing verse of Dharaṇyādi Varga is a colophon and is counted in the total. Translations are by the authors. No second edition or manuscript was collated. therefore,that depart from usual classical teaching are therefore reported as readings of this edition and are not treated as established doctrine. 2.3 Verse analysis The unit of analysis is the verse (Śloka). Verse ranges that carry a single stated topic were assigned to a content domain, and these domains organise Section 3. Verses without a single stated topic are shown as not itemised (Figure 2). Numerical statements, including verse and page counts, taste combinations, states of the Doṣa, divisions of time and units of measure, were checked by arithmetic. Earlier Sanskrit parallels were recorded at chapter level. 2.4 Contemporary comparators and grading of correspondence Comparators were chosen purposively from internationally recognised guidance and peer-reviewed literature in the domains in which the text states rules, vocabulary or units: raw-drug collection and quality, disease and anatomical terminology, pharmaceutical practice and measures, and sustainability. A smaller set of sources was taken for taste, food incompatibility, constitution and time. No systematic search was made, and the comparison makes no claim to completeness. Each correspondence was graded by consensus of the authors into four categories. There was no independent second rater, so the grades are interpretive judgements and not measurements. A direct correspondence means that the classical passage and the modern source serve the same function, act on the same unit of analysis and give an output of comparable form, such as a rule, list or unit; a rule counts as direct only when the classical passage states a quantity or specification that can be checked against the modern source, and qualitative rules were graded at best as partial. A partial correspondence means that the function is shared but the unit of analysis or the form of output differs. Contextual correspondence means that the same subject is addressed in modern terms without functional equivalence. An exploratory link is a mechanistic or practical connection that has been proposed in the literature but has not been tested for the classical statement. The grades describe the form of the comparison and not the validity of either system.

3.1 Position and scope Table 1 gives the position, printed pages, verse count and main content of the four Varga. Together they contain 406 verses in 68 printed pages [1]. Figure 1 shows how the four chapters divide the setting of drug use, and Figure 2 shows the distribution of verses by content domain. Table 1. Position of the four conceptual Varga in the Rāja Nighaṇṭu [1] Varga Position Printed pages Verses Main content Dharaṇyādi 2nd 16 to 28 71 Land, mountains and trees; Nakṣatra Vṛkṣa; rules for the use of drugs Manuṣyādi 18th 575 to 590 123 Persons, life stages, parts of the body, Dhātu Rogādi 20th 618 to 638 104 Disease names, dosage forms, Kvātha, diets, the physician, Rasa Sattvādi 21st 639 to 656 108 Guṇa types, Doṣa timings and states, divisions of time, units of measure Total 68 pages 406 Figure 1. Setting of drug use covered by the four conceptual Varga and the contemporary domains to which each relates. Figure 2. Distribution of verses by content domain in the four Varga. Verse ranges that carry no single stated topic are shown as not itemised (33 verses in Rogādi and 9 in Sattvādi). 3.2 Dharaṇyādi Varga Dharaṇyādi Varga has seventy-one verses. It opens with synonyms for the earth (verses 1 to 3) and classifies land by fertility, soil and water source (verses 4 to 14). Ūrvarā land yields all grains, and the text names clay (Mṛttikā), saline (Kṣāra), desert (Maru), dry Jāṅgala, gravelly (Śārkara) and sandy (Saikata) land. Land is also Nadīmātṛka (watered by rivers), Devamātṛka (by rain) or Dvaimātṛka (by both). Verses 15 to 23 treat mountains, stones, forests and groves, verses 24 to 40 treat trees and their parts from root to fruit, and verse 47 lists grass-like trees (Tṛṇa Vṛkṣa). Verses 41 to 46 form the Nakṣatra Vṛkṣa passage. Verse 41 announces the trees of the Nakṣatra as indicated in the authoritative texts (Āgama), worthy of worship and conducive to long life through both cultivation and protection. Verses 42 and 43 name twenty-seven trees, one for each Nakṣatra from Aśvinī, and verse 44 gives the count (Table 2). Verse 45 states that a person who, blinded by pride, makes medicine from the tree of his own birth Nakṣatra loses longevity, prosperity, wife and son, whereas this fortune increases through cultivation and the like. Verse 46 states that the teaching is explicit in the Bṛhat Suśruta, Nāradīya, Nārāyaṇī and other Tantra texts and, as the commentary reads it, that one should not use the tree of one's birth Nakṣatra even after learning its medicinal use from renowned physicians. Table 2. The twenty-seven Nakṣatra Vṛkṣa of Dharaṇyādi Varga, verses 42 and 43: name in the verse, proposed identity and status [1] No. Nakṣatra Name in the verse Proposed identity Basis and status 1 Aśvinī Viṣadru Strychnos nux-vomica L. Conventional; commentary gloss Viṣatinduka; a toxic species 2 Bharaṇī Dhātrī Phyllanthus emblica L. Conventional 3 Kṛttikā Taru-Hemadugdhā Ficus racemosa L. Conventional; usual equivalent Udumbara 4 Rohiṇī Jambū Syzygium cumini (L.) Skeels Conventional 5 Mṛgaśīrṣā Khadira Senegalia catechu (L.f.) P.J.H. Hurter & Mabb. Conventional 6 Ārdrā Kṛṣṇa Unresolved Read as a separate tree; Kṛṣṇāguru (Aquilaria Lam. species) suggested, untested 7 Punarvasu Vaṃśa Bamboo; candidate Bambusa bambos (L.) Voss Tentative; the name does not fix the species 8 Puṣya Aśvattha Ficus religiosa L. Conventional 9 Āśleṣā Nāga Mesua ferrea L. Conventional; commentary gloss Nāgakeśara 10 Maghā Vaṭa Ficus benghalensis L. Conventional 11 Pūrva Phalgunī Palāśa Butea monosperma (Lam.) Taub. Conventional 12 Uttara Phalgunī Plakṣa Ficus virens Aiton Conventional 13 Hasta Ambaṣṭha-Taru Unresolved No confident equivalent established 14 Citrā Bilva Aegle marmelos (L.) Corrêa Conventional 15 Svātī Arjuna Terminalia arjuna (Roxb. ex-DC.) Wight & Arn. Conventional 16 Viśākhā Vikaṅkata Candidate Flacourtia indica (Burm.f.) Merr. Tentative; candidate only 17 Anurādhā Sakesara Candidate Mimusops elengi L. Tentative; gloss Nāgakeśara duplicates No. 9 18 Jyeṣṭhā Śambara Unresolved Gloss Arjuna duplicates No. 15 19 Mūla Sarja Shorea robusta C.F.Gaertn. or Vateria indica L. Contested; neither binomial preferred 20 Pūrva Āṣāḍhā Vañjula Candidate Calamus rotang L. Tentative; candidate only 21 Uttara Āṣāḍhā Sapānasa Candidate Barringtonia acutangula (L.) Gaertn. (through the gloss Nicula), or Artocarpus heterophyllus Lam. if read as Sa-Panasa Tentative; two competing readings 22 Śravaṇa Arka Calotropis procera (Aiton) W.T. Aiton or Calotropis gigantea (L.) W.T. Aiton Contested; neither binomial preferred 23 Dhaniṣṭhā Śamī Prosopis cineraria (L.) Druce Conventional 24 Śatabhiṣā Kadamba Neolamarckia cadamba (Roxb.) Bosser Conventional 25 Pūrva Bhādrapadā Āmra Mangifera indica L. Conventional 26 Uttara Bhādrapadā Nimba Azadirachta indica A. Juss. Conventional 27 Revatī Madhuka Madhuca longifolia (J.König ex L.) J.F. Macbr. Conventional Botanical names follow the International Code of Nomenclature for algae, fungi, and plants (Madrid Code) [10], with authorities in the standard abbreviated form. Status: conventional, the usual equivalence of the Sanskrit name; tentative, a candidate or genus-level identification; contested, two binomials are current and neither is preferred; unresolved, no confident equivalent established. The list differs in several Nakṣatra from other regional lists [11]. Seventeen of the twenty-seven identifications are conventional, five are tentative, two are contested and three are unresolved, so ten are not confident. The count of twenty-seven depends on reading Kṛṣṇa and Vaṃśa as two trees. The commentary glosses Kṛṣṇavaṃśa as the single tree Kālāvāsa, and a single-tree reading would leave twenty-six names and move every later tree one Nakṣatra earlier. The two-tree reading rests on the count alone and is held as a hypothesis, because fitting a reading to an expected total is partly circular. The glosses of Śambara (Arjuna) and Sakesara (Nāgakeśara) duplicate trees already listed, which is a reason for caution with the commentary. Sapānasa may also be read as Sa-Panasa, the jackfruit tree assigned to Uttara Āṣāḍhā in the list of Mariappan and colleagues [11]. Verses 48 to 68 set out principles for the use of drugs. Each rule addresses one source of variability in the raw material: identity, part, place, season, freshness or formulation default. Fresh drugs are potent, dry drugs moderate and decayed drugs without effect (verse 48), and certain drugs are potent when fresh, with dry material sometimes taken in double quantity (verse 49). This is reported as a textual rule only, and no dose conversion is drawn from it. Eight kinds of Vīrya are listed in verse 54 (Śīta, Uṣṇa, Rūkṣa, Snigdha, Tīkṣṇa, Mṛdu, Picchila and Viśada). Most of these are Guṇa in the usual classification, and the word is used here for these potencies and not for vigour, the sense in which it appears among the stated benefits in Table 3. Drugs grown in cremation grounds, on anthills and on ground fouled by urine are rejected (verse 56). Verse 57 gives the season for each part: Kanda in Hemanta, Mūla in Śiśira, Puṣpa in Vasanta, Pravāla and Patra in Nidāgha, and plants of muddy water in Śarad. Verse 58 adds that trees such as Nimba, Udumbara and Jambū are best in their own season. Parts of one plant may differ in action (verse 59), and drug names change with every twelve Yojana of distance (verse 60). Where a formula is silent, the root is the part and rainwater the water, quantities are left to the physician, and a preferred member is named for each class of ingredient (verses 61 to 66). Verses 69 to 71 are closing verses, the last a colophon. 3.3 Manuṣyādi Varga Manuṣyādi Varga is the most extensive of the four, with 123 verses. Verses 1 to 18 give terms for the person, man, woman, wife, the four social classes, mixed lineages and children by age, and verses 19 to 28 give life stages. A long section (verses 29 to 76) names the parts of the body from head to foot, including Āmāśaya between the navel and the breast and Pakvāśaya below the navel. Verses 77 to 86 give body-relative measures, and the Marma, named as seats of life (Jīvasthāna), are recorded in verses 64 and 87 to 89. Verses 90 to 94 name excretions and skin changes. Verses 95 to 106 name the seven Dhātu (Rasa, Rakta, Māṃsa, Meda, Asthi, Majjā and Śukra) in their order of formation, followed by the brain, intestine and spleen. Verses 107 to 112 give terms for Nāḍī, Snāyu, Kaṇḍarā, skull, vertebrae, long bone, rib and Srotas, and verses 113 to 121 give philosophical terms: Ātmā, Prakṛti, Ahaṃkāra, Manas, the three Guṇa, the senses with their objects and the five Mahābhūta. Verse 122 states that the Varga was made to guide the physician in deciding the causes (Nidāna) of disease, and verse 123 is the colophon. Verse 19 gives named stages for the first years of life, from Arbhaka (fifteen days to one month) and Potaka (three months) to Śiśu (one year), Baṭu (three years) and Māṇavaka (seven years). Verse 20 and 21 give two schemes for later life. In the first, Bāla extends to 15 years, Kumāra to 30, Yuva to 50, and Vṛddha follows. In the second, Kaumāra ends at 5 years, Paugaṇḍa at 10, Kaiśora at 15, and Yauvana follows. Two schemes in adjacent verses suggest descriptive age bands and not rigid clinical categories. 3.4 Rogādi Varga Rogādi Varga has 104 verses. It records disease names (verses 1 to 31) and then treatment, health and diet. The disease names follow rules that can be stated. A disease is called Vātaja, Paittika, Śleṣmika or Sānnipātika according to the Doṣa involved (verse 31), and compound names add a site to a symptom word, as in Śiraḥśūla for pain in the head (verse 25). Several names for Rājayakṣmā appear in verse 2. Verse 37 names five dosage forms, Rasa, Cūrṇa, Kaṣāya, Avaleha and Kalka, which verses 38 and 39 define. Verse 43 takes up the vehicle (Anupāna) and, as the commentary reads it, distinguishes the vehicle given after a delay (Krāmaṇa) from that given at night (Pācana). Verses 68 to 70 grade the diets suited to the sick, Maṇḍa, Peyā, Vilepī and Yavāgū, by the proportion of liquid to grain. Verses 40 to 42 name seven decoctions (Kvātha) for their intended action: Pācana, Śodhana, Kledana, Śamana, Dīpana, Tarpaṇa and Śoṣaṇa. They are boiled down until one half, one half, one twelfth, one fourth, one eighth, one sixth, one fifth and one sixteenth of the volume remains, respectively. The design ties concentration to therapeutic goal, but the order is not monotonic with the stated action, since Śodhana at one twelfth is more concentrated than Śamana at one eighth, and the verses give no rationale. The fractions are reported as printed and as the commentary reads them. Whether each denotes the volume that remains or the proportion by which the liquid is reduced was not confirmed against another edition. Verse 48 describes the competent Vaidya as born in a good family, learned, pure, steady, skilled, impartial and free from greed, and verse 49 names five kinds of unfit physician: the unsteady, the harsh, the greedy, the one who is himself diseased and the poorly trained. Verses 52 to 54 give a rule for digging medicinal plants with an invocation. In verse 53 the digger recalls that the great deities have dug the herb and asks it for success. Verses 76 to 100 form a compact treatise on taste. The six Rasa are named with an illustrative source and with the effects of moderate and excessive use (Table 3). Verse 89 pairs the tastes with the Doṣa: Katu with Kaṣāya relieve Kapha, Madhura with Tikta relieve Pitta, and Lavaṇa with Amla relieve Vāta. Verse 91 names salt with sweet and pungent with sweet as incompatible and treats Kaṣāya as a neutral taste that shows the same quality in every mixture. The commentary adds bitter with sweet. This sits uneasily with verse 89, which pairs Madhura with Tikta as relieving Pitta, and the difference between the verse and the commentary was not resolved here. Table 3. The six Rasa in Rogādi Varga (verses 77 to 87 and 92) [1] Rasa Illustrative source Stated benefit Stated harm in excess Vipāka Madhura Ikṣu (Saccharum officinarum L.) Increases hair, steadies the body, gives strength, Ojas and Vīrya Prameha, coldness, dullness, weak digestion Amla Lavaṇa Saindhava (rock salt) Appetising, kindles digestion, laxative Early ageing, aggravated Pitta, laxity, Kuṣṭha Lavaṇa Tikta Nimba (Azadirachta indica A. Juss.) Destroys worms, relieves Kuṣṭha, fever, cough and burning Rājayakṣmā Katu Kaṣāya Pūga (Areca catechu L.) Checks swelling, stimulates digestion Loss of strength, laxity, pallor Madhura Amla Cincā (Tamarindus indica L.), Mātuluṅga (Citrus medica L.) Pleasant, appetising, kindles digestive fire Giddiness, Kuṣṭha, Kapha type of Pāṇḍu, thinness, cough Tikta Katu Marica (Piper nigrum L.) Relieve Kapha, throat disease, swelling, poor digestion Loss of Vīrya and strength, many diseases Tikta The Vipāka scheme of verse 92 differs from the threefold Vipāka of the Caraka Saṃhitā [12]. Lavaṇa is given a Lavaṇa Vipāka and Amla a Tikta one, and the logic of the transformations is not explained. Verses 94 to 100 count the mixtures of tastes taken one to six at a time. The counts, 6, 15, 20, 15, 6 and 1, sum to 63 and equal the binomial coefficients for six items. This is the full set of non-empty combinations of six items, and the enumeration is not peculiar to this text. The Caraka Saṃhitā also enumerates 63 combinations of the six Rasa (Sūtrasthāna 26) [12]. 3.5 Sattvādi Varga Sattvādi Varga has 108 verses. It opens with the three Guṇa, Sattva, Rajas and Tamas, which verses 1 and 2 assign to Kapha, Pitta and Vāta in that order, a pairing that differs from several later accounts. Verse 10 states that Prakṛti is determined by the Guṇa together with the Doṣa, and verses 10 to 16 describe the Sāttvika, Rājasika and Tāmasika types and their mixtures by diet, behaviour, dreams and build. The typology joins somatic, dietary, behavioural and dream features and ranks mixed types in a way that joins clinical and moral judgement, so it is treated as a descriptive framework and not as a diagnostic instrument. Verses 17 to 19 give the times at which each Doṣa aggravates (Table 4). Vāta aggravates in the rainy season, in the afternoon and early morning, after digestion and with sweet food, which runs against the usual teaching that the sweet taste pacifies Vāta. Pitta aggravates at the end of the rain, at midday and midnight, and during digestion. Kapha aggravates in the cold season and spring, in the forenoon and at nightfall, and after eating. Table 4. Seasons, parts of the day and digestive phases at which each Doṣa aggravates (Sattvādi, verses 17 to 19) [1] Doṣa Season Part of the day Digestive phase Vāta Rainy season Afternoon and early morning After digestion; also, with sweet food Pitta End of the rains Midday and midnight During digestion Kapha Cold season and spring Forenoon and nightfall After eating Verses 20 to 26 enumerate sixty-three states of the three Doṣa by increase and decrease. Verses 21 to 25 give 25 states of increase, 25 of decrease and 12 mixed states, which make 62, and a last state of natural balance (Sāmya) makes 63. Each Doṣa may be increased, more increased or most increased (Vṛddha, Vṛddhatara, Vṛddhatama), or reduced in the corresponding grades. Verse 26 directs the physician to apply the treatment that suits the state. Verses 27 to 86 classify time from the smallest unit to the year: the watches of the day and night, the fortnight, Pūrṇimā and Amāvāsyā, the months, the six Ṛtu and the Ayana, with the properties of sunlight, shade, moonlight and darkness (verses 40 to 53). Verse 82 adds that the six Ṛtu also occur within each day, each lasting ten Nāḍī from sunrise. Verses 87 to 100 give the winds of the seasons and the ten directions. The Varga closes with units of length, volume and weight (Table 5), stated to be useful to the physician (verse 103). Table 5. Units of measure stated in Sattvādi Varga [1] Category Relations stated in the text Verses Time 10 Pala = 1 Kṣaṇa; 6 Kṣaṇa = 1 Nāḍī (or Ghaṭikā); 2 Ghaṭikā = 1 Muhūrta; 7.5 Nāḍī = 1 Prahara; 8 Prahara = 1 day and night 32 and 36 Length 8 Yava = 1 Aṅgula; 24 Aṅgula = 1 Hasta; 4 Hasta = 1 Daṇḍa; 2000 Daṇḍa = 1 Krośa; 4 Krośa = 1 Yojana 101 and 102 Grain volume 4 Muṣṭi = 1 Niṣṭikā; 2 Niṣṭikā = 1 Aṣṭikā; 2 Aṣṭikā = 1 Kuḍava; 4 Kuḍava = 1 Prastha; 4 Prastha = 1 Āḍhaka; 4 Āḍhaka = 1 Droṇa; 20 Droṇa = 1 Khārī 103 to 105 Drug weight 2 wheat grains = 1 Guñjā; 1.5 Guñjā = 1 Valla; 4 Valla = 1 Māṣa; 4 Māṣa = 1 Niṣka; 4.5 Niṣka = 1 Karṣa (commentary's reading); 4 Karṣa = 1 Pala; 100 Pala = 1 Tulā; 20 Tulā = 1 Bhāra 106 3.6 Arithmetic checks Every check that can be made from the verses alone agrees with the stated totals. The verse counts sum to 406 and the printed pages (13, 16, 21 and 18) to 68. The taste combinations sum to 63, which is 2⁶ minus 1, and the states of the Doṣa (25 + 25 + 12 + 1) also sum to 63. In the divisions of time a Nāḍī has 60 Pala, so a day and night has 60 Nāḍī and 30 Muhūrta, and six Ṛtu of ten Nāḍī each fill the day at about four hours per Ṛtu. In length, 1 Daṇḍa equals 96 Aṅgula and 1 Yojana equals 32,000 Hasta. In volume, 1 Droṇa equals 64 Kuḍava and 1 Khārī equals 1,280 Kuḍava. In weight, 1 Karṣa equals 18 Māṣa on the commentary's reading and 1 Bhāra equals 2000 Pala. The seven Kvātha grades match the seven named actions one to one. These checks test internal consistency and the reliability of the verse numbering. They give no metric values, because unit relations differ between classical sources.

4.1 Textual function and antecedents The four Varga extend the Rāja Nighaṇṭu from a list of drugs to the setting in which a drug grows, the person who receives it, the disease for which it is used, and the time and measure of its use. Verse 122 states that Manuṣyādi Varga was made to guide the physician in deciding the causes of disease, and verse 103 of Sattvādi Varga gives its measures as useful to the physician. Such statements may be conventional statements of purpose and are not evidence of clinical use. Manuṣyādi Varga also holds Varṇa, social-role and philosophical terms typical of the human-classification chapter of general Sanskrit lexica, so the more economical reading is that the author imported a standard lexicographic chapter and added medical terms. Several rule-type contents have antecedents in classical literature. The eightfold Vīrya of verse 54 of Dharaṇyādi Varga corresponds to the potencies enumerated in the Caraka Saṃhitā (Sūtrasthāna 26) [12], and the six Rasa correspond to the treatment of taste in the Caraka and Suśruta Saṃhitā [12,13]. The qualities of the physician in verses 48 and 49 of Rogādi Varga parallel the discussion of the physician in the Caraka Saṃhitā [12], and the Doṣa timings of verses 17 to 19 of Sattvādi Varga resemble the teaching of the Aṣṭāṅga Hṛdaya (Sūtrasthāna 1) [14]. The count of 63 taste combinations is a combinatorial result that the Caraka Saṃhitā also gives [12], and graded permutations of Doṣa increase and decrease are discussed in the Saṃhitā commentarial tradition [13], so neither count can be presented as peculiar to this text. Other contents differ from the earlier sources. The five dosage forms of verse 37 are not the five basic preparations of the Śārṅgadhara Saṃhitā (Madhyama Khaṇḍa 1), namely Svarasa, Kalka, Kvātha, Hima and Phāṇṭa [15], and the Vipāka scheme of verse 92 differs from the threefold scheme of the Caraka Saṃhitā [12]. Rules on the collection of drugs also occur in the Saṃhitā literature (for example Caraka Kalpasthāna 1 and Suśruta Sūtrasthāna 36) [12,13], and those of Dharaṇyādi Varga should be read against these passages at verse level before any claim of originality is made. The relevance of the collection rules and measures to present guidance does not depend on where they originated. 4.2 Raw-drug collection, identity and habitat The rules of verses 48 to 66 of Dharaṇyādi Varga and verses 52 to 54 of Rogādi Varga address the same variables that the WHO guidelines on good agricultural and collection practices treat as determinants of the quality of herbal raw material: place, time, plant part and method of collection [16]. The WHO guidelines also call for controlled, season-appropriate collection as a safeguard against depletion of wild populations [16], and the WHO, IUCN and WWF guidelines and the international standard for sustainable wild collection add sustainability to quality [17,18]. Table 6 sets the classical rules beside their modern counterparts and proposes, for each, a field that a collection record could carry. The correspondence is close in function and in the variables addressed, but the classical rules are qualitative. Neither chapter gives a quantitative standard or a specification that can be verified, the invocation of verse 53 has no modern counterpart, and the rejection of cremation grounds and anthills (verse 56) corresponds in effect to contamination avoidance, although its classical rationale may be ritual or hygienic. Under the grading rule of Section 2.4 the correspondence is therefore partial. Table 6. Classical rules for raw-drug collection, proposed fields for a collection record, and counterparts in modern guidance Classical rule and verses Variable Proposed record field Counterpart in modern guidance Fresh drugs potent, dry drugs moderate, decayed drugs without effect (Dharaṇyādi, 48 and 49) State of the material Condition at collection; drying and storage method Handling, drying and storage as determinants of quality [16,19] Drugs from cremation grounds, anthills and fouled ground rejected (Dharaṇyādi, 56) Collection site Site description and contamination status Site selection and avoidance of contaminated areas [16] Best season for each plant part; certain trees best in their own season (Dharaṇyādi, 57 and 58) Time and plant part Date, season and part collected Harvest timing by season and plant part [16] Parts of one plant differ in action (Dharaṇyādi, 59) Plant part Part used, stated explicitly Plant part as a determinant of quality [16,19] Drug names change with every twelve Yojana of distance (Dharaṇyādi, 60) Identity Botanical name, vernacular names and region Botanical identification and vernacular-name variation [19,20] Root and rainwater as defaults where a formula is silent; a preferred member for each class of ingredient (Dharaṇyādi, 61 to 66) Formulation default Part and water specified when a formula is reconstructed Plant part specified in pharmacopoeial monographs [20] Uprooting from a clean place at the proper time, with an invocation (Rogādi, 52 to 54) Method of collection Method and time of harvest Collection method and timing [16]; the invocation has no counterpart Cultivation and protection of the useful trees (Dharaṇyādi, 41) Sustainability Source (wild or cultivated) and quantity harvested Conservation and cultivation of medicinal plants [8,17,18] Verse 60 records the vernacular-name variation that complicates botanical identification today, and verses 61 to 66 fix defaults where a formula is silent. Quality-control standards treat correct identification, plant part and state of the material as basic determinants of quality [19], and the Āyurvedic Pharmacopoeia of India specifies identity and part for each monographed drug [20]. The classical statements are observations and formulation defaults and not testable identity standards, so the correspondence is partial. They nevertheless state, in a text meant for physicians, a problem that is still unresolved for many classical plant names [3]. The statement that fresh drugs are potent and dry drugs moderate (verses 48 and 49) concerns a variable that phytochemistry also recognises, but it gives no quantity and no drug-specific rule. It is a testable direction, for example by comparing fresh and dried material of a named drug by chromatographic fingerprinting [19], and not an established standard. Verses 4 to 14 classify land by fertility, soil, moisture and water source and link the classes to crops. Modern pharmacognosy links the origin and growing conditions of a medicinal plant to its bioactive content, as in the Chinese Daodi concept [21], and recent reviews address climatic and ecological change [9,22]. Good practice guidance requires documentation of site, harvest and post-harvest handling [16]. The land typology supplies a classical vocabulary for provenance, but its verses do not state an effect of land class on drug quality, so the correspondence is contextual. 4.3 Terminology and clinical documentation A materia medica needs a vocabulary for the patient to whom a drug is applied. Manuṣyādi Varga supplies terms for persons by sex, class and life stage, for body parts and for the seven Dhātu, and Rogādi Varga supplies disease names with stated naming rules. Modern anatomy fixes one preferred term for each structure [23], whereas Manuṣyādi Varga lists synonyms for body parts and related terms. The nearest contemporary parallels are the WHO international standard terminologies on Āyurveda [5], the NAMASTE portal of the Ministry of Ayush, which lists standardised terms and morbidity codes [6], and the ICD-11 chapter for traditional medicine conditions, which allows dual coding with biomedical diagnoses although traditional medicine remains weakly represented in routine health data [7]. All bring many names for one entity under a controlled vocabulary. Rogādi Varga is, however, a list of disease names with naming rules and not a hierarchical coded classification, so the correspondence is partial. Naming rules are the most useful feature for terminology work. A prefix for the Doṣa involved (verse 31) and a compound of site and symptom (verse 25) make a term analysable into parts, which is the property that terminology mapping requires. The bounded set of disease names in verses 1 to 31 is therefore a suitable pilot set for mapping classical entities to coded terms. Rājayakṣmā, for example, is commonly correlated with pulmonary tuberculosis, but the correlation is not exact, and a coded mapping would need clinical input. The age bands of verses 19 to 21 differ from modern paediatric and geriatric definitions and are descriptive, not dosing categories. The positional terms Āmāśaya and Pakvāśaya (verses 29 to 76) and the seats of life named as Marma are useful in teaching the seats of undigested and digested matter and of vulnerable sites, but the verses list them only as sites. No term-level mapping to any standard was made in this study. A mapping exercise would need a verse-numbered list of the disease names, a confidence grade for each proposed mapping as in Table 2, and clinical review. 4.4 Pharmaceutical concepts and units of measure The five dosage forms of verse 37 are defined in verses 38 and 39 and differ from the five basic preparations of the Śārṅgadhara Saṃhitā [15]. The seven Kvātha grades state a process parameter, the fraction of volume that remains after boiling, and tie it to an intended action. The printed fractions are non-monotonic and have not been checked against another edition, so they are reported as readings that need confirmation. If they are confirmed, a testable design would prepare each grade from one authenticated raw-drug lot with a fixed drug-to-water ratio and fixed heating conditions and compare extract solids and marker compounds by chromatographic fingerprinting [19], with the usual reduction to one quarter as the reference grade [15]. The distinction between Krāmaṇa and Pācana vehicles is reported as the commentary reads it, and no pharmacokinetic claim is drawn from it. The Māgadha-Māna of the Śārṅgadhara Saṃhitā [15] is the scheme generally followed in Āyurvedic pharmacy, with the Māṣa commonly taken as 750 mg, the Śāṇa as 3 g, the Karṣa as 12 g and the Pala as 48 g. In Sattvādi verse 106, 2 wheat grains make 1 Guñjā, 1.5 Guñjā make 1 Valla and 4 Valla make 1 Māṣa, so the Māṣa contains 6 Guñjā, as in the Māgadha-Māna. Four Māṣa make the Niṣka, which corresponds to the Śāṇa, also called Ṭaṅka, if the two names denote the same unit. This equivalence is assumed here and not shown. From the Karṣa upward the chain (4 Karṣa to the Pala, 100 Pala to the Tulā and 20 Tulā to the Bhāra) is the same as in the Māgadha-Māna. The metric values are derived conventions (the Māṣa as six Guñjā of about 125 mg), and pharmacopoeial or formulary tables may use rounded equivalents that differ from them [20], so the table in use should be stated whenever a dose is converted. The only difference is at the Karṣa. The commentary's reading of 4.5 Niṣka makes it 18 Māṣa, or 13.5 g, against 16 Māṣa (12 g). The difference carries through to the Pala (54 g against 48 g), the Tulā and the Bhāra at a constant ratio of 1.125 (Figure 3). A dose stated in Karṣa or Pala would therefore differ by 12.5 per cent between the two readings. The practical weight of this depends on the drug. It matters for drugs with a narrow margin between effective and toxic dose, such as processed seed of Strychnos nux-vomica or root of Aconitum species, and for mineral preparations, whereas for bulk decoction ingredients it lies within the natural variation of raw-material composition. A reading of 4 Niṣka would remove the difference. Whether 4.5 is a printed variant, a commentarial reading or a distinct usage cannot be decided without other editions. The comparison covers the weight chain only, and the word Pala denotes both a unit of weight and a unit of time. The correspondence with the Māgadha-Māna is direct for the weight chain. Pharmacopoeial and formulary conversion tables should be used for regulatory or dosing purposes [20]. Figure 3. Mass of each weight unit computed from Sattvādi verse 106 on the commentary's reading of 4.5 Niṣka to the Karṣa, compared with the Māgadha-Māna scheme. The Māṣa is taken as 750 mg and the Niṣka is assumed equivalent to the Śāṇa. 4.5 Diet and taste The graded diets of verses 68 to 70 (Maṇḍa, Peyā, Vilepī and Yavāgū) are defined by the proportion of liquid to grain, which is a parameter that can be stated and standardised. They resemble in kind the stepwise progression from thin liquids to solid food prescribed as Saṃsarjana-Krama after purificatory therapy [12], but the verses do not tie each grade to a Doṣa or to a stage of recovery, so the link is exploratory. The proportions themselves were not tabulated in this study. Modern taste biology recognises dedicated receptor systems for five basic tastes [24], a conventional list to which further candidates such as fat taste are being proposed [25]. Madhura, Lavaṇa and Amla correspond broadly to sweet, salty and sour, and Tikta to bitter. Umami has no counterpart, and Katu and Kaṣāya do not map to basic taste classes. Pungency is a chemesthetic and not a gustatory sensation, and piperine, the pungent principle of Marica (Table 3), acts on the human capsaicin receptor TRPV1 [26], while other pungent principles, such as allicin and allyl isothiocyanate, act on the related channel TRPA1 [27], so Katu as used in Rogādi Varga spans chemically distinct agents. Astringency is attributed to the interaction of polyphenols with salivary proteins [28], which is why Kaṣāya has no receptor-class counterpart. In the classical account Rasa is first a quality perceived by the tongue, whereas Vīrya and Vipāka are inferred from action, so a comparison with receptor biology concerns sensation only, and the correspondence is contextual. The incompatible taste pairs of verse 91 may be set beside general reviews of Viruddha Āhāra [29], which do not test the pairs named. Table 3 lists Pūga (Areca catechu L.) as the illustrative source of Kaṣāya. Areca nut is classified by the International Agency for Research on Cancer as carcinogenic to humans [30], and Strychnos nux-vomica L. and Calotropis R.Br. species, which appear in Table 2, yield drugs of recognised toxicity. These entries are illustrative or botanical, carry no therapeutic recommendation, and should not be read as a basis for household use. 4.6 Constitution, time and states of the Doṣa The Guṇa typology of verses 10 to 16 describes a mental constitution (Mānasa Prakṛti) that is conceptually separate from the Doṣa-based Prakṛti. The nearest contemporary analogue is psychometric work on the three Guṇa as personality dimensions [31], and a validated instrument relating the two constitutional schemes would be needed before any clinical use. The sixty-three states of the Doṣa give a finer vocabulary than the simple increase-or-decrease scheme of most teaching and invite comparison with the classical staging of Doṣa (Ṣaṭkriyākāla). The 25, 25, 12 and 1 distribution offers a simple scheme for teaching graded Doṣa disturbance. Metabolism and drug disposition are organised by circadian clocks [32,33]. The Doṣa windows of verses 17 to 19 are defined by season, part of the day and digestive phase and not by clock time, which complicates any mapping to hormonal rhythms. Verse 82 adds a day-level scheme in which each of the six Ṛtu occupies about four hours. The traditional dosing terms before food, after food and at bedtime refer mainly to timing relative to a meal or to sleep. No data link the Doṣa periods to measured biological rhythms, and any use of them for timing drugs or meals remains a hypothesis. The apparent aggravation of Vāta with sweet food should be checked in other editions before it is interpreted. 4.7 Sustainability: a hypothesis-generating reading Medicinal plant use faces pressure from over-harvest and climate change. Conservation literature reports that 50,000 to 80,000 flowering plant species are used medicinally and that about 15,000 are threatened [8]. Climatic and ecological change alters metabolite profiles and suitable habitat [9], and a framework for sustainable use stresses ecosystem factors and conservation [22]. In this setting the land typology of Dharaṇyādi Varga supplies a classical vocabulary for recording provenance, and the seasonal and part-wise rules of verses 57 to 59 may be read as an early statement of time-specific and part-specific harvest. The classical rationale concerns quality and not stock, and modern guidance adds quantitative limits and monitoring [18]. Two features of the text bear on sustainable use. Where a formula is silent the root is the default part (verses 61 to 66). For perennial plants this default implies uprooting, and the choice of plant part bears on harvest impact, which sustainable wild collection standards address [18], so a modern reconstruction of such formulae should specify the part and consider substitution by aerial parts where the evidence allows. Verse 53 of Rogādi Varga also places the act of digging within a rule of respect for the plant. The invocation has no regulatory counterpart, but it is an ethnobotanical record of a cultural attitude to harvest. The Nakṣatra Vṛkṣa passage is the clearest candidate for a sustainability reading, and it remains a hypothesis. Verse 41 joins reverence to cultivation and protection, and verse 45 restricts the medicinal use of one tree for each person while promising increase through cultivation. Social taboos and sacred groves are recognised forms of local resource management [34,35], and the trees of the Nakṣatravana tradition have been compared for medicinal properties and volatile compounds [11], but that work does not test a conservation function. Other readings fit the text equally well, including ritual or astrological avoidance with no resource logic and, for some trees, caution about a toxic drug. As a conservation measure the mechanism is limited, because each person is restrained from one tree of twenty-seven and several of the trees are widely cultivated. The more plausible mechanism lies in the reverence and cultivation described in verses 41 and 45. A planting list cannot replace a check of the conservation status of each species [36] and of applicable regulation, and Aquilaria Lam., a candidate for Kṛṣṇa, is a genus listed under the international trade convention [37]. The Nakṣatra Vṛkṣa list is best used as an ethnobotanical basis for community planting and awareness, with species status audited first. 4.8 Clinical and educational relevance No clinical claim is made, because no clinical data was assessed. Clinical relevance is considered at three levels: vocabulary and recording, pharmaceutical standardisation, and the teaching of Dravyaguṇa and Kāyacikitsā (Table 7). For recording, the disease-naming rules and the anatomical and Dhātu terms give a classical vocabulary that could be mapped to coded terms. For pharmaceutical standardisation, the collection rules, the Kvātha grades and the unit chain state parameters that can be documented or tested. For teaching, the six Rasa and their incompatible pairs suit dietetics and Viruddha Āhāra counselling, the graded diets and Saṃsarjana-Krama suit post-therapy regimens, the sixty-three Doṣa states suit the teaching of staging, and the qualities of the physician give a professional conduct code for discussion. These are proposals for teaching and for later testing and not findings. Table 7. Concepts of the four Varga, their contemporary and clinical relevance, and the grade of correspondence Concept Varga and verses Contemporary and clinical relevance Correspondence Weights and measures Sattvādi 101 to 106 Dose standardisation; the Karṣa reading affects doses by 12.5 per cent Direct Collection rules: state, site, season, plant part Dharaṇyādi 48 to 59; Rogādi 52 to 54 Collection records, authentication and quality assurance aligned with good collection practice Partial Raw-drug identity, regional names, formulation defaults Dharaṇyādi 60 to 66 Authentication and prevention of misidentification; specification of part and water Partial Anatomical and Dhātu terms Manuṣyādi 29 to 112 Teaching vocabulary; mapping to standard terminologies Partial Disease names and naming rules Rogādi 1 to 31 Pilot set for mapping to ICD-11 and NAMASTE terms Partial Land classes Dharaṇyādi 4 to 14 Vocabulary for provenance and habitat records Contextual Six Rasa and incompatible pairs Rogādi 76 to 100 Dietetic teaching; Viruddha Āhāra counselling; taste biology Contextual Guṇa types Sattvādi 10 to 16 Descriptive mental constitution; psychometric comparison Contextual Qualities of the physician Rogādi 48 and 49 Professional conduct for teaching Contextual Five dosage forms and seven Kvātha grades Rogādi 37 to 42 Extraction parameters testable by chromatographic fingerprinting Exploratory Graded diets Rogādi 68 to 70 Liquid-to-grain proportion as a standardisable parameter; stepwise diet progression Exploratory Nakṣatra Vṛkṣa Dharaṇyādi 41 to 46 Community planting and awareness after status audit Exploratory Doṣa timings and 63 states Sattvādi 17 to 26 Staging vocabulary; chronobiological hypotheses Exploratory 4.9 Limitations One edition and one Hindi commentary were used, and no second edition or manuscript was collated. This is the main limitation of the study. Several readings, namely the pairing of Guṇa with Doṣa, the Vipāka scheme, the Kvātha fractions, the aggravation of Vāta with sweet food and the 4.5 Niṣka of the Karṣa, depart from usual classical teaching and could not be checked against other editions, so they may reflect printing, commentarial or reading differences and are not offered as doctrine. The botanical identifications are the authors' own and were not checked against specimens, floras or pharmacognostic monographs, ten of the twenty-seven are not confident, and the conservation status of the trees was not audited. Comparison with earlier Sanskrit sources is at chapter level, and whether other Nighaṇṭu texts contain comparable chapters was not surveyed. The comparators were chosen purposively without a systematic search. The grades of correspondence were assigned by consensus of the authors without an independent second rater, so they are interpretive. Because modern parallels can be found in retrospect for almost any classical statement, the grades describe the form of a comparison and do not support claims of anticipation or validity. The metric equivalents of the units are conventions, the weight comparison assumes that Niṣka and Śāṇa are equivalent, the proportions of the graded diets and the list of disease names were not tabulated, and no term-level mapping to ICD-11 or the WHO terminologies was made. 4.10 Future work The first task is collation of the four Varga against a later printing of the Tripathi commentary, the edition of P.V. Sharma and catalogued manuscripts, with independent Sanskrit review of the translations. Verse-level comparison with the Amarakośa and with the Caraka, Suśruta, Aṣṭāṅga Hṛdaya and Śārṅgadhara texts would test the distinctiveness of these chapters, and a chapter-level survey of other Nighaṇṭu texts would test the premise stated in the Introduction. The botanical identity of each tree should be fixed against type material and regional names and checked against IUCN Red List and CITES status. Disease names of Rogādi Varga could be mapped to ICD-11 and NAMASTE terms, the liquid-to-grain proportions of the graded diets tabulated, the unit relations compared in full of the pharmacopoeial scheme, the Kvātha grades tested by extraction studies, and the collection rules compared with seasonal phytochemical data from Indian studies.

The Dharaṇyādi, Manuṣyādi, Rogādi and Sattvādi Varga expand the Rāja Nighaṇṭu into an ordered lexicon of material source, patient, disease, time and measurement. Their clearest contemporary relevance lies in documenting the variables of raw-material collection, in terminology, and in weights and measures. Collection, identity and terminology content corresponds in part, and the weight chain corresponds directly with the Māgadha-Māna except at the Karṣa, a point that matters for dose and needs verification in other editions. Sustainability, pharmacokinetic and chronobiological links and the definitive botanical identity of the Nakṣatra Vṛkṣa remain provisional unless supported by dedicated textual and empirical evidence, and the originality of the rules awaits comparison with the lexicographic and Saṃhitā sources. Author Contributions Prof. (Dr.) Anu Prabha: Conceptualization, Methodology, Investigation (reading of the source text), Writing, original draft. Dr. Sandhya Vasantrao Shinde: Investigation (literature review), Formal analysis, Writing, review and editing. Dr. Harikrishnan S: Formal analysis (clinical review of the disease-naming, Doṣa-state and constitution content), Writing, review and editing. Dr. Irfan A K: Investigation (Dravyaguṇa and botanical literature, including the Nakṣatra Vṛkṣa identifications), Writing, review and editing. Dr. Vijay Mukund C: Formal analysis (clinical review of the dosage-form, Kvātha, graded-diet and Saṃsarjana-Krama content), Writing, review and editing. All authors read and approved the final manuscript. Conflict of Interest The authors declare that there is no conflict of interest associated with this article. Source of Funding This article received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. Acknowledgement The authors acknowledge the Department of Dravyaguṇa Vijñāna and the Department of Kāyacikitsā, SAM College of Āyurvedic Sciences and Hospital, SAM Global University, Raisen; the Department of Dravyaguṇa Vijñāna, Sardar Ajit Singh Smriti Ayurvedic Mahavidyalaya, Bhopal; and the Department of Pañcakarma, Ranidullaiya Smriti Ayurved PG Mahavidyalaya and Chikitsalay, Bhopal, Madhya Pradesh, for providing the academic environment for this work.

Tripathi ID, editor. Rāja Nighaṇṭu of Narahari Paṇḍita, with Dravyaguṇaprakāśikā Hindi commentary. Introduction by Dvivedī V. 1st ed. Varanasi: Krishnadas Academy; 1982. (Krishnadas Āyurveda Series 5). 2. Meulenbeld GJ. A History of Indian Medical Literature. Groningen: Egbert Forsten; 1999-2002. 3. Thomas V, Nair SNV, Ved DK, Shankar D. Controversial identities of medicinal plants in classical literature of Ayurveda. J Ayurveda Integr Med. 2020;11(4):565-72. 4. Dobriyal RM, Ananthanarayana DB. Controversial nomenclature of Ayurvedic drugs: challenges for scientists. Pharmacogn Rev. 2009;3(5):1-7. 5. World Health Organization. WHO international standard terminologies on Āyurveda. Geneva: World Health Organization; 2022. Available from: https://iris.who.int/handle/10665/365543 6. Thrigulla SR, Narayanam S. Initiatives: National Ayush Morbidity and Standardized Terminologies Electronic (NAMASTE) portal. J Ayurveda Integr Med. 2023;14(4):100781. doi: 10.1016/j.jaim.2023.100781 7. Lee YS, Huang Y, Wardle J, Witt CM, Lee MS. International Statistical Classification of Diseases and data gaps in traditional medicine. Bull World Health Organ. 2025;103(11):744-6. doi:10.2471/BLT.25.293540 8. Chen SL, Yu H, Luo HM, Wu Q, Li CF, Steinmetz A. Conservation and sustainable use of medicinal plants: problems, progress, and prospects. Chin Med. 2016; 11:37. doi:10.1186/s13020-016-0108-7 9. Takubessi MI, Jalil B, Heinrich M. The impact of climate change on medicinal plants and natural products: a scoping review. Front Pharmacol. 2025; 16:1697581. doi:10.3389/fphar.2025.1697581 10. Turland NJ, Wiersema JH, Barrie FR, Gandhi KN, Gravendyck J, Greuter W, et al., editors. International Code of Nomenclature for algae, fungi, and plants (Madrid Code). Regnum Vegetabile 162. Chicago: University of Chicago Press; 2025. doi:10.7208/chicago/9780226839479 11. Mariappan P, Kiran KR, Swathy PS, Kaniyassery A, Thorat SA, Bhagyashree P, et al. Sacred groves and Nakshatravan trees: a comparative analysis for their medicinal properties and volatile compounds for human health. S Afr J Bot. 2022; 151:623-38. doi: 10.1016/j.sajb.2022.08.029 12. Sharma RK, Dash B, translators. Agniveśa's Caraka Saṃhitā (text with English translation and critical exposition based on Cakrapāṇi Datta's Āyurveda Dīpikā). Varanasi: Chowkhamba Sanskrit Series Office; 1976 onward. 13. Sharma PV, editor and translator. Suśruta Saṃhitā (with English translation of text and Ḍalhaṇa's commentary). Varanasi: Chaukhambha Visvabharati; 2001. 14. Srikantha Murthy KR, translator. Vāgbhaṭa's Aṣṭāṅga Hṛdayam. Varanasi: Krishnadas Academy; 1991. 15. Srikantha Murthy KR, translator. Śārṅgadhara Saṃhitā. Varanasi: Chaukhambha Orientalia; 1984. 16. World Health Organization. WHO guidelines on good agricultural and collection practices (GACP) for medicinal plants. Geneva: World Health Organization; 2003. Available from: https://iris.who.int/handle/10665/42783 17. World Health Organization, International Union for Conservation of Nature, Worldwide Fund for Nature. Guidelines on the conservation of medicinal plants. Gland: IUCN; 1993. 18. Medicinal Plant Specialist Group, IUCN Species Survival Commission. International standard for sustainable wild collection of medicinal and aromatic plants (ISSC-MAP), version 1.0. Bonn: Bundesamt für Naturschutz; 2007. 19. World Health Organization. Quality control methods for herbal materials. Geneva: World Health Organization; 2011. 20. Government of India, Ministry of Health and Family Welfare. The Āyurvedic Pharmacopoeia of India, Part I. New Delhi: Government of India; 1989 onward. 21. Zhao ZZ, Guo P, Brand E. The formation of Daodi medicinal materials. J Ethnopharmacol. 2012;140(3):476-81. doi: 10.1016/j.jep.2012.01.048 22. Mykhailenko O, Jalil B, McGaw LJ, Echeverría J, Takubessi M, Heinrich M. Climate change and the sustainable use of medicinal plants: a call for "new" research strategies. Front Pharmacol. 2025; 15:1496792. doi:10.3389/fphar.2024.1496792 23. Federative International Programme for Anatomical Terminology. Terminologia Anatomica. 2nd ed. 2019. Available from: https://fipat.library.dal.ca/ta2/ 24. Chandrashekar J, Hoon MA, Ryba NJP, Zuker CS. The receptors and cells for mammalian taste. Nature. 2006;444(7117):288-94. doi:10.1038/nature05401 25. Besnard P, Passilly-Degrace P, Khan NA. Taste of fat: a sixth taste modality? Physiol Rev. 2016;96(1):151-76. doi:10.1152/physrev.00002.2015 26. McNamara FN, Randall A, Gunthorpe MJ. Effects of piperine, the pungent component of black pepper, at the human vanilloid receptor (TRPV1). Br J Pharmacol. 2005;144(6):781-90. doi: 10.1038/sj.bjp.0706040 27. Bautista DM, Movahed P, Hinman A, Axelsson HE, Sterner O, Högestätt ED, et al. Pungent products from garlic activate the sensory ion channel TRPA1. Proc Natl Acad Sci U S A. 2005;102(34):12248-52. doi:10.1073/pnas.0505356102 28. Lesschaeve I, Noble AC. Polyphenols: factors influencing their sensory properties and their effects on food and beverage preferences. Am J Clin Nutr. 2005;81(1 Suppl):330S-5S. doi:10.1093/ajcn/81.1.330S 29. Sabnis M. Viruddha Ahara: a critical view. Ayu. 2012;33(3):332-6. doi:10.4103/0974-8520.108817 30. International Agency for Research on Cancer. Betel-quid and areca-nut chewing and some areca-nut derived nitrosamines. IARC Monogr Eval Carcinog Risks Hum. 2004; 85:1-334. 31. Wolf DB. A psychometric analysis of the three Gunas. Psychol Rep. 1999;84(3 Pt 2):1379-90. 32. Panda S. Circadian physiology of metabolism. Science. 2016;354(6315):1008-15. doi:10.1126/science. aah4967 33. Ayyar VS, Sukumaran S. Circadian rhythms: influence on physiology, pharmacology, and therapeutic interventions. J Pharmacokinet Pharmacodyn. 2021; 48:321-38. doi:10.1007/s10928-021-09751-2 34. Colding J, Folke C. Social taboos: "invisible" systems of local resource management and biological conservation. Ecol Appl. 2001;11(2):584-600. 35. Gadgil M, Vartak VD. Sacred groves of Western Ghats of India. Econ Bot. 1976; 30:152-60. 36. IUCN. The IUCN Red List of Threatened Species. Gland: International Union for Conservation of Nature. Available from: https://www.iucnredlist.org 37. Convention on International Trade in Endangered Species of Wild Fauna and Flora. Appendices I, II and III. Geneva: CITES Secretariat. Available from: https://cites.org/eng/app/appendices.php