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Herbal research – need to redirect priorities
Prof. S. Balasubramanian | Thursday, November 25, 2010, 08:00 Hrs  [IST]

Hundreds of laboratories throughout the world are working day and night on herbs to find out new active principles. Once an active principle is discovered, it is like striking a goldmine, as there is tremendous scope for exploiting it commercially. Hence there is a mad rush ignoring the already available herbal formulations used for centuries by ancient systems of medicine in many countries. For example, we have Ayurveda and Siddha systems of medicines practised for thousands of years in north India and south India respectively. Similarly there are Unani and Oriental systems of medicine practised in many Asian countries. These systems of alternative medicine have wealth of medicines whose standards cannot be demonstrated as per western standards. Our Indian labs are also following the same off beaten foot prints of western countries which do not have this inheritance.

Results of contemporary research on herbs
The results published by the scientists of contemporary research on herbs, invariably declare isolation and pharmacological activity of one or two compounds of new plants which neither leads to commercial application nor support the ancient systems. Only a pathetic minuscule fraction of these research findings are worth patenting by researchers themselves and as a result these researches lead us to nowhere. In the last few decades we could get only handful of active principles like vinblastine and vincristine from Vinca rosea and diosgenin as a precursor for steroidal synthesis. Glycosides of Digitalis and alkaloids of Ergot and Reserpine were the other discoveries worth mentioning. Thus only a minimum success could be achieved for such a massive effort.

It doesn't mean that we should stop researching on new plants. There are more than 2,00,000 to 2,50,000 flowering plants in some 300 families and 10,000 genera. Only a fraction of total spices have been analysed so far. Hence our efforts should continue here. At the same time we must not ignore the already available herbal formulations. Why it is ignored? The reason is simple; there is nobody to push for it.

Discovering a new, active principle involves big money whereas standardization of existing herbal formula incubates for a long time to give a handsome return. That is why there are nil or few patrons to fund such research proposals. But with standardization of existing herbal formulations, peoples are going to enjoy the benefit and the system of medicine gets much needed recognition. It is a pity in our quest to get a new uncertain entity; we lose the existing valuable ones in our hands.

How best the herbal formulations are?
How many of our herbal researchers have full-at least- partial knowledge about our ancient herbal formulations mentioned in Ayurveda and Siddha literatures? Once you started reading the technique involved in the preparation of these formulations, you will be astonished. The ancient Vaidya or physicians of these systems have used many novel methods to cultivate, collect and prepare the herbs for using in formulations.

They have adopted some wonderful techniques to detoxify (suddhi, puta) and/or extract the active principle into the formulations. Thus, for example, the preparation of Arista or Asava-an Ayurvedic formulation containing alcohol soluble principles of the plant material involve the production of alcohol in-situ, that is self generated alcohol has been used to prepare Arista or Asava! A casual reading of the method of preparation of Arista make us wonder how the ancient people carried out anaerobic fermentation process without the use of modern inoculums [and microbiology!] thousands of years ago. Similar are the methods of preparations of other formulations like Arka, Bhasma, Churna, Girta, Guda, Lehya, Lepa, Sindura, Taila, etc.

Among these formulations the Sindura in Ayurveda or Chendooram in Siddha attracted bitter criticism from the western scientists, because they use obviously toxic substances like sulphur, mercury and metals like gold, silver, copper etc as their ingredients. How a metal can be digested or assimilated by our body is the question asked by these scientists.

On going through the method of preparation of these formulations, one could come across rigorous methods, often difficult and time-consuming processes. If you follow these formulation techniques as per the ancient text , the resulting product is a very fine powder, in colloidal dimensions and can be assimilated by our body, the ancient literatures claim. The process involves repeated burning [puta], ashing [Bhasma] or sublimating, sometimes up to 60 to 100 times! Who knows the resulting product may consist of nano particles! Remember the recent scientific pronouncements that declare "when particles are reduced to nano size, they have completely different and non existing properties than parent material" Thus herbal formulations cannot be brushed aside as such just like that. Take it seriously and it goes without saying, it is our duty to standardize it to the satisfaction of western scientists to save our pride and keep our head high.

It is true no serious scientific toxicological studies were carried out on these formulations. It is time to take up such studies also and prove these formulations are harmless, at the same time effective. Dismissing them without such studies amount to insulting our forefathers and their knowledge. Don't deliver judgment before trial!

Individual active principle vs formulations:
Medicinal plant analysis is a very difficult area. Unlike synthetic drugs, we do not have any prior information about its constituents, its quantity or properties. Plant being a living thing and dynamic, you cannot predict when a particular constituent is synthesized or destroyed by the plant, how much and where, and its degradation or bioconversion product. Hence most of the attempts to isolate an active principle end in failure.

For example the plant Valerian [Valeriana officinalis, Valerinaceae] has long been used as sedative, but scientists could not isolate active principle responsible for it from the plant. The known constituents volatile oil and alkaloids do not have any sedative properties. After a long struggle only in 1970, it was discovered the plant contains esters named valepotriates and derivatives of valerenic acid which are having sedative properties. [Trease and Evans].

Not isolating the active principle even from the known plant is the result of many research projects and when questioned, the practitioner of alternative systems of medicine, request us not to attempt to isolate an active principle responsible for pharmacological action. They say it is the combined effect of all plants of the formulation that cure the disease and there is no point in trying to isolate the single compound from one of the constituent plant of the formulation. They request us to look at the formulation in its entity.

It is true, because the extracts of the plant(s) prescribed will contain a wide range of plant metabolites, of which some will be therapeutically active. "It is maintained that this admixture, containing a spectrum of constituents of the plant cell is more readily assimilable and gives rise to far fewer side effects than a single isolated principle. Also, a number of constituents, which on their own may appear pharmacologically inactive, combine synergistically to produce therapeutic effects. Thus Convalleria majalis [Lilly of the valley] is highly esteemed in the treatment of certain heart conditions. It contains glycosides similar to those of Digitalis but having a subtly different cardoactive effect. This treatment is indicated by F.F.Hyde [Pharm.J. 1974,212,495] may be combined with or followed by five or six other plants, which combined to give a gentle potentiating activity and allow the reduction in dosage of other cardio vascular remedies" [Pharmacognosy by Trease and Evans].

To put it simply, a plant extract has many chemicals, some known, some unknown, some in detectable quantities, some in traces missed in analysis. It is observed in many herbal formulations "Trikadugam" [Gingiber officinalis, Piper nigrum, & Piper longum] is included.Why these drugs are repeatedly used in different herbal formulations? Recent researches have proved that they improve the absorption and thereby bioavailability of other active ingredients. Thus they act as bio-enhancers, solubilizers or appetizers (to stimulate the gastric secretion and digestion).

Some plant extracts contain antioxidant principles whose value has been proved beyond doubt. Similarly other ingredients are used as counter principles to nullify or reduce the harmful effects of main ingredient. These techniques are not new to those who are familiar with allopathic formulation techniques - the pharmacy graduates - but when the same techniques are applied by ancient peoples in the herbal formulations we are not ready to believe or accept it! We must shed our inhibitions and pre-conceived notions about the herbal formulations and use our full modern scientific knowledge to standardize the herbal formulations. But the biggest challenge before the manufacturers is how to produce uniform products from non-uniform raw materials, and avoid batch to batch variation.

Priorities:
Hence scientists must give priority to develop fool proof method of analysis for each and every herbal formulation which can establish its potency, quantity and quality. To do this effectively the basic requirement is building in the quality in the manufacturing stage itself with allowance for zero error as followed in the manufacture of allopathic formulation.

As the herbal formulation manufacturing techniques mentioned in ancient literature are nearly okay and followed for centuries, fine-tuning them may be sufficient. Hence our efforts can be directed towards methods of analysis of final products. When extracts from standard raw materials [herbs] grown in controlled environment is used for manufacture according to standard manufacturing processes, the resulting final product will be of standard uniform quality- we can expect.

To prove this expectation right is the duty before us. Develop newer method of analysis for each formulation; simplify them so that those methods can be followed by the laboratories attached to manufacturing concerns. Once well established, they can be made mandatory. Then export those formulations with FDA and other countries approval.
Be proud of our ancestors and the nation!

The author is ex. president, Indian Pharmacy Graduates Association, Madurai

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