Practicing herbs as the natural remedies for the disease management and its prevention is dated back to the ancient period. Diverse arrays of healing systems are grown up in the grounds of such practices around the globe. Among them, Ayurveda, the indigenous medical system of India places an important role in maintaining the health and prevention of diseases. Our ancestors keenly observed the nature and they turned this observational knowledge into a perceptional level. A plant grows on rocks by breaking the stones using its roots may helpful in removing the urinary stones formed inside the body. This insight made them to observe the nature more and thus developed the treatment modalities for various illnesses. This theory is known as Lokapurushasatmyavada explained in Charakasamhitha and is one of the fundamental principles of Ayurveda. A rational, well developed pharmacological and pharmaceutical basis lays the foundation of therapeutics in Ayurveda. As per the shastra, four important factors (Paadachathushtaya) are needed for a successful treatment. The factor which is important in the treatment right after the Vaidya is Dravya (Drug). Without the real knowledge in dravya, a Vaidya cannot make the treatment fruitful. Thus Dravyagunavijnana becomes an integral part of all the branches of Ayurveda.
Ayurveda is nothing but the science which imparts knowledge about life (Ayu) through the analysis of ayushyaani (substances which promotes longevity) and anaayushyanidravyas (substances which hamper the longevity). Dravyagunavijnana is the branch of Ayurveda which exclusively mentioned for the detailed study of such dravya and its attributes. It is a comprehensive discipline which embraces various aspects of knowledge about the identification, collection and classification of drugs; their physical and chemical properties; biotransformation and metabolic activities; uses, dosage and therapeutic actions; compatibility, synergism and vehicle; incompatibility and toxicity, and their different pharmaceutical applications.
The word Dravyagunavijnana comprised of two words dravya and guna. Here, the latter covers guna( qualities) and karma (functions), which are the inherent parts reside in dravya. In Ayurveda, every dravya is considered as panchabhouthika. The proportion of panchamahabhootha determines the guna of a dravya. Based on that proportion, dravya does the karma, the therapeutic action in the body. The qualities present in the dravya are also present in the body. Because “deho hi aaharasambhava” (body is made up of the food we consumed). Hence, the similar (samanya) qualities of a dravya will increase the similar qualities in the body and dissimilar (vishesha) qualities will do the opposite. It is the dravya which responsible for the vrddhi(increase) and kshaya( decrease) of dosha, dhathu&mala inside the body and influence the srothamsi (channel in the body).
There are so many classifications of dravya are available in the classics. The most fascinating one is based on its source.
• Oudbhida (Plant origin)
• Jangama (Animal origin)
• Parthiva (Mineral origin)
There are subdivisions under each category, which covers most of the natural things in the universe. There are around 1200 medicinal plants are mentioned in the samhithas. Some more are added during the nighantu period and Ayurveda says, “Jagatyevam Anoushadam”. Every plant in the universe is having the medicinal properties when it is used by a Vaidya with proper yukthi. So one can identify such medicinal plants, only with the thorough knowledge in assessing its physical and innate powers, here shows the importance of Dravyagunavijnana.
Ayurveda attributes the mode of action of the drug to the five principles (Rasapanchaka) namely Rasa, Guna, Virya, Vipaka and Prabhava. Majority of the times these gunas (attributes) may not be measurable but inferred through their pharmacological actions. The study of the biological and therapeutic effects of the drugs (what drug does to the body) are well explained by these principles which can be identified as pharmacodynamic principles of Ayurvedic pharmacology. These pharmacodynamic principles also influence the pharmaco-kinetics (study of the absorption, metabolism and excretion of drugs and their relationship to the pharmacological response) of the drugs. Routes of drug administration play an important role in the elucidation of drug action. A drug may exert different effects when given by different routes. Madanaphala when given orally acts as Vamana dravya (emetic) and if administered with Vasti dravyas (ingredients of enema) facilitates for its quicker transportation in the colon and acts as a synergistic for toning up the nervous system or relieving intracranial tension. Yashtimadhu (Glycyrrhiza glabra) when used in an optimum dose act as shamanoushadhi and in higher doses, it acts as a vamanopaga (enhancing the vamana). The potent drug Lashuna (Allium sativum) is disagreeable for internal administration as kalka/ swarasa, when it made into a ksheerapaka, it becomes easy to consume and the potency will be optimised. So, Maatra, Kalpana (Dosage forms), Sevanakaala (Time of intake) and anupaana (vehicle/carriers) are important factors regarding the drug action.
In the modern pharmacology, the drug action is explained through its bio molecules which are the secondary plant metabolites. The following important pharmacologically active principles in medicinal plants include;
a. Alkaloids (Basic substances containing cyclic nitrogen, which are insoluble in water but combine with acids to form water soluble salts) which is found in Guduchi (Tinospora cordifolia), Kaalmegh (Andrographis paniculata) etc
b. Glycosides (Ether like combinations of sugars with other organic structures): Sathavari (Asparagun racemosa), Triphala
c. Oils (Fixed oils, volatile oils and mineral oil):Eranda (Ricinus communis), Tila (Sesamum indicum), Lavanga (Syzygium aromaticum)
d. Resins (insoluble in water and soluble in alcohol): Guggulu (Commiphora mukul) ,Asana (Pterocarpum marsupium)
e. Oleoresins (mixtures of volatile oils and resins): Hingu (Ferula asafoetida), Shallaki (Boswellia serrata)
f. Gums (secretory products of plants and are dispersible in water): Khadira (Acacia catechu), Snuhi (Euphorbia neriifolia)
g. Tannins (Non-nitrogenous plants constituents and precipitate proteins of cells: Asoka (Saraca asoca), Kutaja (Holarrhena antidysenterica)
h. Antibacterial substances fungi and moulds: Shilapushpa (Parmeliaperlata)
Every human being is unique in their phenotypical and genotypical manner, that’s why Ayurveda gives more importance to personalised cure for diseases and its prevention. Similarly, the dravya also works in a unique manner for each individual, that’s may be the reason why we may fail to establish the drug action of Ayurvedic herbs through scientific researches. It does not mean that it is unscientific but has to access through much broader, deep and sophisticated scientific techniques.