Abstract

Rasa, Vipaka, Guna,Virya and Prabhava are the five components of Rasapanchak and these are the basic descriptors of ayurvedic pharmacology, i.e. Dravyaguna Vigyana. Still many research works and dissertation are not being done on the basis of Rasapanchaka of the drug but the molecular basis is focused in prime, especially for the ethnomedicines which are not described in classics or if described their rasapanchaka is not specified. So there is a need of developing an experimental method to evaluate their rasapanchaka.

In Ayurvedic system of medicine the drug is used as whole, unlike modern system of medicine in which the fractional component or a synthesized molecule is used as a drug. On the other side a plant or any single drug contains numerous phytochemicals. Studying the pharmacological properties of single molecule or a class of molecule cannot solve the purpose in ayurvedic way but assessing the Rasadi padarth of the whole drug can put footmarks towards the basic principles of Ayurveda.

Many scholars across the globe have done many experimental studies to specify the rasa of a crude drug. The development of electronic tongue (e-tongue) with differential sensing is a major step towards assessing the rasa of a drug. Chromatography is another tool for the qualitative evaluation of a drug. Many attempts are being done to generate Botanical Reference material for different rasa present in a drug in the light of chromatographical fingerprinting. The discovery of taste receptors spread in extra oral locations like stomach, intestine, heart, adipose tissue etc. as a diffuse chemosensory system throws light on the several principals of ayurvedic pharmacology especially the rasapanchaka. Knowing the mechanism of activation and suppression of these extraoral taste receptors one can design and experimental model to derive the rasa of a particular drug.

Classical description of vipaka says that it is reflected in its effects. Taking this in consideration scholars hypothesised that Vipaka can be assessed by experimentally evaluationg the effects of a drug on the quantity of stool, urine and increase in proliferation of sperm cells.

Applying the law of thermodynamics virya are said to be the change in enthalpy. Exothermicity and endothermicity are shown experimentally in-vitro by usna and sheeta virya dravya respectively. Further thermal transduction exhibited by certain chemosensors present in various organs also falls in parallel with the two viryas described in Ayurveda.

Prabhava being ‘achintya’ or non derivable can’t be generalized, but specific actions found in experimental studies which are not found in drugs with similar organoleptic characters can be considered as prabhava.

All these above experiments, hypothesis and botanical reference materials can be collectively used as a tool to evaluate the rasapanchaka of a drug. This review article is an attempt to narrate some of the important works done in this field.

Keywords: Rasapanchak, Ayurvedic pharmacology, Chromatography, Extraoral taste receptors, Thermodynamics, experimental evaluation.