Changes

#Assessment of ''panchamahabhuta'' in a substance can be carried out by taking into consideration, the most conspicuous characteristic of each ''mahabhuta''. For example, ''gandha guna, rasa guna, rupaguna, sparsh guna'' and ''shabd guna'' are chief characteristics of ''prithvi, jala, agni, vayu'' and ''akasha mahabhutas'' respectively. By these organ-specific methods, it becomes easy to assess the ''panchbhutika'' constitution of the substance. Rest of the gunas given for each mahabhuta should be clinically evaluated.

#Assessment of ''panchamahabhuta'' in a substance can be carried out by taking into consideration, the most conspicuous characteristic of each ''mahabhuta''. For example, ''gandha guna, rasa guna, rupaguna, sparsh guna'' and ''shabd guna'' are chief characteristics of ''prithvi, jala, agni, vayu'' and ''akasha mahabhutas'' respectively. By these organ-specific methods, it becomes easy to assess the ''panchbhutika'' constitution of the substance. Rest of the gunas given for each mahabhuta should be clinically evaluated.

#The gustatory effect of the initial, as well as final contact of the drug either in the dry or wet state with the tongue, is known as ''rasa'' or taste. ''Rasa'' is the only principle of drug action which can be directly perceived (''pratyaksha gamya''). This is to be assessed in human volunteers by a single blind method with a performa consisting of chief characteristics of each ''rasa''. As mentioned in [[Charaka Samhita]] (su. 26/73-79) sugarcane, milk, and sugar candy are all said to be sweet, but there is an obvious difference in the taste of these substances. So, the intensity of each ''rasa'' can be assessed by taste threshold method. Electronic tongue if developed may help to validate the information about the intensity of ''rasa''.   

#The gustatory effect of the initial, as well as final contact of the drug either in the dry or wet state with the tongue, is known as ''rasa'' or taste. ''Rasa'' is the only principle of drug action which can be directly perceived (''pratyaksha gamya''). This is to be assessed in human volunteers by a single blind method with a performa consisting of chief characteristics of each ''rasa''. As mentioned in [[Charaka Samhita]] (su. 26/73-79) sugarcane, milk, and sugar candy are all said to be sweet, but there is an obvious difference in the taste of these substances. So, the intensity of each ''rasa'' can be assessed by taste threshold method. Electronic tongue if developed may help to validate the information about the intensity of ''rasa''.   

3. Veerya and vipaka are inferred through the activities or final effects (karma) produced by intake of drug/diet.

#''Veerya'' and ''vipaka'' are inferred through the activities or final effects (''karma'') produced by intake of drug/diet.

4. Vipaka is a pharmacokinetic principle, and its activities are referred at the level of koshtha (mutra and purisha), dhatu (Shukra) and doshas. Rasa and veerya are pharmacodynamic principles. Assessment of veerya and vipaka are to be evaluated clinically.

#''Vipaka'' is a pharmacokinetic principle, and its activities are referred at the level of ''koshtha'' (''mutra'' and ''purisha''), ''dhatu'' (''shukra'') and ''doshas''. ''Rasa'' and ''veerya'' are pharmacodynamic principles. Assessment of ''veerya'' and ''vipaka'' are to be evaluated clinically.

5. The concept of virudhaahara indicates the concepts of incompatibility and allergic reactions.  For example, neither honey nor ghee is toxic to the body but if they both taken in equal quantity becomes unwholesome. A combination of it must be subjected to chemical analysis and pharmacological evaluation to assess the adverse effects.  

#The concept of virudhaahara indicates the concepts of incompatibility and allergic reactions.  For example, neither honey nor ghee is toxic to the body but if they both taken in equal quantity becomes unwholesome. A combination of it must be subjected to chemical analysis and pharmacological evaluation to assess the adverse effects.  

6. Treatment of disease induced by virudhaahara includes vamana, virechna, administration of antagonistic drugs and adaptation of prophylactic measures.  

6. Treatment of disease induced by virudhaahara includes vamana, virechna, administration of antagonistic drugs and adaptation of prophylactic measures.  

7. The concept of prabhava clearly indicates the principle which contributes to the specific activity of the drug and is inexplicable in nature.  Danti root which acts as a purgative loses its effectiveness when soaked in water and administered. Observations indicate that danti has water soluble qualities that contribute to its ability to work as a purgative ref. Once the causative principle is identified, the activity of danti can be explained in a rational way, and it cannot be quoted as an example of prabhava. In the light of photochemical research, the explanation of drug action becomes rational and the prabhava, a specific principle can be deleted from the list of principles of drug action.

7. The concept of prabhava clearly indicates the principle which contributes to the specific activity of the drug and is inexplicable in nature.  Danti root which acts as a purgative loses its effectiveness when soaked in water and administered. Observations indicate that danti has water soluble qualities that contribute to its ability to work as a purgative ref. Once the causative principle is identified, the activity of danti can be explained in a rational way, and it cannot be quoted as an example of prabhava. In the light of photochemical research, the explanation of drug action becomes rational and the prabhava, a specific principle can be deleted from the list of principles of drug action.

  It is quite apparent that the acharyas formulated the hypothesis that explained the workings of drugs after observing various activities. In the context of the failure of the hypothetical principles to explain the drug action in a rational way, the concept of prabhava was formulated which may be interpreted as an empirical principle. Drugs with similar chemical structure should have similar actions. But it is not possible to predict the activity of a drug entirely by its chemical structure. Drugs with similar structures but having entirely different effects are known as isomers, for example, Antazoline & Tolazoline appear chemically similar but former is an antihistamine and the latter is an adrenergic blocking agent. Conversely, many dissimilar chemical agents have similar action, for example, phenobarbitone, chloralhydrate, and paraldehyde are all depressants of the central nervous system. The concept of prabhava may be interpreted using the concept of isomerism6.

  It is quite apparent that the acharyas formulated the hypothesis that explained the workings of drugs after observing various activities. In the context of the failure of the hypothetical principles to explain the drug action in a rational way, the concept of prabhava was formulated which may be interpreted as an empirical principle. Drugs with similar chemical structure should have similar actions. But it is not possible to predict the activity of a drug entirely by its chemical structure. Drugs with similar structures but having entirely different effects are known as isomers, for example, Antazoline & Tolazoline appear chemically similar but former is an antihistamine and the latter is an adrenergic blocking agent. Conversely, many dissimilar chemical agents have similar action, for example, phenobarbitone, chloralhydrate, and paraldehyde are all depressants of the central nervous system. The concept of prabhava may be interpreted using the concept of isomerism6.

References

=== References ===

1. K. Nishteswar, Basic concepts of ayurvedic pharmacology, Chaukhamba Sanskrit Series Office, Varanasi,2008, pp: xii  

1. K. Nishteswar, Basic concepts of ayurvedic pharmacology, Chaukhamba Sanskrit Series Office, Varanasi,2008, pp: xii