Dravyaguna - Vijnanam (A TextBook of Pharmacology)

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Ayurveda came about as a science at a time when Spiritualism and Yogic procedures failed to stop the spread of diseases and epidemics. Indian sages evolved the tenets of samanya (generic concomitance), vishesha (variant factor), guna (quality), dravya (substance), karma (action) and samavaya (inseparable concomitance) for raising the span of life. These principles form the substances of therapeutics. The subject of Ayurveda is divided into eight disciplines (Astanga Ayurveda) and all the specialties include the application of dravyas (food/drug) to achieve the ultimate goal i.e., restoration of health. In view of the importance of Dravya, Guna and Karma among six principles, Acharya Yadavji Trikamji , the erudite scholar of Ayurveda, formulated the subject of Dravyaguna Vijnana which is being taught currently at undergraduate and postgraduate courses. Central Council of Indian Medicine (CCIM) formulated the curriculum and divided the subject matter into two papers. First paper deals with fundamental concepts of Dravyaguna Sastra and second paper contains the details of Pharmaco-therapeutics of various drugs. The book on second paper is already published and the information about concepts mentioned in the first paper is presented in this book. Recent researches about these concepts are quoted according to necessity while explaining the principles of drug action.

Dr. K. Nishteswar obtained BAMS degree (1976) from Andhra University, MD (1980) from Gujarat Ayurveda University and Ph.D. (1997) from University of Pune. He also completed Sanskrit Bhashakovida (1975) from Bharatiya Vidya Bhawan and Diploma in AIDS (2004) from IGNOU. He received State Best Teacher Award from Government of Andhra Pradesh during 2001. He has been awarded several gold and silver medals in recognition of his merit and theses on various topics like diabetes, hypertension and cardiovascular disorders. He delivered Keynote lectures and guest lectures in several National and International Seminars. Dr. Nishteshwar has authored more than 50 books and has also published nearly 105 papers in various standard journals. He has also served as CCIM member and executive editor for AYU, an international journal.

The subject of Dravyaguna mainly deals with drug actions (KARMA) and the principles (GUNA) governing various activities along with modifying factors (Kala, Desha, Kalpana, Matra etc.,). Dravyaguna is not enumerated among eight branches (Ashtanga) of Ayurveda. The author of Rajanighantu asserts that Kayachikitsa is the subject which includes Dravyabhidhanam (Dravyaguna) and Gadanighraha (prevention and treatment of diseases). According to this definition, it is explicit that Dravyaguna is a clinical branch of Ayurvedic medicine and should be understood as clinical pharmacology. Charaka, while defining 'Ayurveda', mentions that the science of longevity mainly deals with Guna and Karma of Ayushya (promoters of longevity) and Anayushya (demoters of longevity) Dravyas. This statement emphasises that Dravyaguna-vijnana is the summum bonum of Ayurvedic therapeutics. Rasa, Guna, Veerya, Vipaka and Prabhava are considered as the principles of drug action. All these five principles (Rasa-panchaka) are also referred to by a common name such as Gunas of a Dravya. According to Ayurvedic science, all matter (Dravya) is constituted by Panchamahabutas (five primordial elements). These Mahabhutas are attributed to certain Gunas which stimulate various activities. Charaka envisaged the definitions of components of drug action viz., Drugs act by virtue of their own nature or by their qualities (Guna) or by both on a proper occasion, in a given location, in appropriate condition and situations. The effect so produced is considered to be their action (Karma) and the key factor responsible for the manifestation of the effect is known as Veerya, which is the Adhishthana (location or site), where these drugs act, Kala when they act, the Upaya how they act, and the Phala what they ultimately achieve.

Of the five principles of Rasapanchaka, Rasa (taste) is given prime importance since it is the only principle perceivable directly (by Pratyaksha-pramana), while the rest of them are inferred by Anumana-pramana (inference). Charaka lays more emphasis on the importance of Rasa and Dosha and quotes "A physician, well acquainted with the classification of Rasa (Rasavikalpajna) and Doshas (Doshavikalpavit) seldom commits blunders in ascertaining the etiology, symptomatology and treatment of diseases". Sixty three types (combinations) of Rasas are enumerated to treat 63 varieties of vitiated Doshic manifestations. Infact, it conveys 63 varieties of Dravya based on Rasa for treating 63 conditions. An essential list consisting of 63 drugs can be formulated and named 'Doshapratyanikaoushadhis'. Though Acharyas mentioned three Gunas for each Rasa (e.g. Guru-Snigdha-Sheeta for Madhurarasa), it was stated that these Gunas are related to Dravya, since the Rasa being a Guna, it cannot have another attribute to it. A question arises here about the action of Rasa and it is deemed that Rasa has to act by its Prabhava.

In such a case, Dravya-prabhava (inexplicable principle) may be classified into six types viz., Madhura-prabhava, Amla-prabhava, Lavana-prabhava etc. While formulating the Rasa-skandha dravya, Acharya Charaka in Vimana-sthana has adopted the criteria such as Madhurani, Madhuraprayani, Madhuravipakani, Madhuraprabhavani. Based on this Rasa-prabhava can be interpreted as Dravya-prabhava. If the drug action is explained with the help of Guna, it becomes rational. Most potent Gunas out of 20 Gunas (Vimshati gunas) are referred to as Veerya. The activity of Vipaka (a pharmacokinetic principle) is also interpreted in terms of Gunas viz., Snigdha, Ruksha, Guru, Laghu etc., Veerya is categorized into either two or eight types. In the discussions held earlier to decide the number of Rasas, the Royal sage Varyovida postulated Guru, Laghu, Sheeta, Ushna, Snigdha and Ruksha as Shad-rasas. These six Gunas must be considered as true Veeryas as they dominate Shadvidhopakrama (Six forms of therapy).

To sum up - Rasa is a useful tool to identify the Panchabhautik constitution of Dravya (Rasena-anumiyate dravyam) and helps in deducing its spectrum of activity. It need not be considered as a specific principle of drug action. The characteristics of individual Rasas and the diseases engendered due to their over indulgence are attributed to dominant Rasa dravya only.

The concept of Prabhava reflects the ignorance and it need not be considered as principle of drug action. In the 21st century, any drug activity can be precisely explained with the help of chemical constituent of the drug. Vipaka can be considered as a pharmacokinetic principle which helps in the synthesis of Guna (Veerya), and is the initiator of drug action. Ultimately Veerya (one or the other Guna out of 20) alone is the principle of drug action and the rest of the four need not be considered as independent principles of drug action.

Rasa is one of the organoleptic characteristics of Dravya, but not a principle of drug action. Drugs administered by other routes (except oral route) minimizes the role of Rasa in explaining drug activity.

Electronic tongue cannot substitute for the biological tongue. In recent researches, taste receptors are identified in other parts of the body like skin, but the validity and sustenance of this concept is doubtful. Acharyas of Ayurveda developed the concepts of drug action, but these concepts lack the wherewithal for objective evaluation.

The views expressed here are based on the authentic references quoted in various Ayurvedic classics. I advise the students of Dravyaguna to give a serious thought to these concepts, and at the same time instruct them not to mention these views while answering the question papers, in the examinations. Teachers need to provide a proper insight into these concepts which will give rise to new research oriented questions in the young minds of students for further development of the science. Panchabhautic concept is the first one dealt with Ayurveda and its implication in Dravyaguna is more specific. The second concept is related to principles of drug action which are explained with regard to Rasapanchaka. The third one is about harvesting methods. Different parts of plant are to be collected in different seasons and recent researches have validated these concepts. Secondary metabolites (Alkaloids, Glycosides, Tannins etc.,) which are responsible for drug activity will vary in quantity in different seasons, while lunar cycles exert great influence on them. Keeping this in view, Acharyas of Ayurveda specified the period of collection of the part used. The fourth important concept is Bhaishajya-kala (period of drug administration), suggested to address the vitiated Doshas in the disease condition. The fifth concept is related to Anupana (vehicle to be administered with or after food/drug). Anupana acts as a synergistic agent and researches validated bioenhancers (eg. Piperine) which facilitate a better therapeutic effect of the administered drug. The sixth concept is related to Bhaishajya-kalpana (different dosage forms) and Matra (posology) and it also plays a crucial role in deciding therapeutic response of drug application.

Considering all these concepts, Central Council of Indian Medicine (CCIM) has drafted a syllabus of Dravyaguna (1st Paper) and formulated certain guidelines. Keeping the curriculum in view, the needful information about these topics has been compiled and presented in this book. The modern pharmacology is also included briefly in the current syllabus. I have proposed to Mr. Rahul Dutt who has specialized in modern pharmacology to prepare the write-up and he readily accepted and carried out the task very precisely. He has incorporated the information about reported pharmacological activities of Ayurvedic herbs in the respective chapters which has improved the utilitarian value of the subject. I consider this as the unique feature of this book.

In the Annexure the information about other Annapana varga (included initially in the CCIM syllabus under first paper and shifted to second paper currently) along with history of Dravyaguna at a glance is furnished.

I wish to acknowledge the timely help extended by my Ph.D. scholars Dr. A. Praveen Kumar and Dr. Sushama Bhuvad in the arrangement of references in the entire text.

I dedicate this volume to Vaidya Bapalal, a doyen in the field of Ayurveda, who rendered yeoman's service to the subject of Dravyaguna as a token of respect. I am beholden to Sri Jamunadasji, Chaukhambha Sanskrit Pratishthan, Delhi for publishing this work. Hope the undergraduate and postgraduate students and the scholars of Ayurveda will benefit from the content of this book.

**Contents and Sample Pages**