How are Science and Technology proven the benefits of Medicinal Plants?

What is a medicinal plant?

A medicinal plant is any plant which, in one or more of its organs, contains substances that can be used for therapeutic purposes or which are precursors for the synthesis of useful drugs. This description makes it possible to distinguish between medicinal plants whose therapeutic properties and constituents have been established scientifically, and plants that are regarded as medicinal but which have not yet been subjected to a thorough scientific study.

There is a growing amount of evidence-based research supporting various botanicals.

There is currently a vigorous debate about whether botanical medicines are effective, and whether it is ever appropriate to use them in a modern medical setting.

Medicinal plants belong to the oldest known health care products that have been used by human beings all over the world and are major components of the formulations used in indigenous system of medicine practiced in many countries. Besides, finding place as health supplements, nutraceuticals, cosmetics, herbal tea etc. there has been a global insurgence of interest, including India, leading to enormous research/activities in the area of medicinal plants.

Evaluating the evidence

In evaluating any clinical study, whether of botanical or pharmaceutical medicines, it is important to pay attention to the quality and design of the study. Factors to consider include:

Sample size (or number of people or medicines being tested)
Length of the study
Dose
Goals of the study and how they were measured
Nature of the medicine being investigated

Effectiveness

Plant medicines have often not been tested systematically, but have come into use informally over the centuries. By 2007, clinical trials had demonstrated potentially useful activity in nearly 16% of herbal medicines; there was limited in vitro or in vivo evidence for roughly half the medicines; there was only phytochemical evidence for around 20%; 0.5% were allergenic or toxic; and some 12% had basically never been studied scientifically.

A 2012 phylogenetic study built a family tree down to genus level using 20,000 species to compare the medicinal plants of three regions, Nepal, New Zealand and the Cape of South Africa. It discovered that the species used traditionally to treat the same types of condition belonged to the same groups of plants in all three regions, giving a “strong phylogenetic signal” .Since many plants that yield pharmaceutical drugs belong to just these groups, and the groups were independently used in three different world regions, the results were taken to mean 1) that these plant groups do have potential for medicinal efficacy, 2) that undefined pharmacological activity is associated with use in traditional medicine, and 3) that the use of a phylogenetic groups for medicines in one region may predict their use in the other regions.

Drug discovery

The pharmaceutical industry has roots in the apothecary shops of Europe in the 1800s, where pharmacists provided local traditional medicines to customers, which included extracts like morphine, quinine, and strychnine. Therapeutically important drugs like camptothecin (from Camptotheca acuminata, used in traditional Chinese medicine) and taxol (from the Pacific yew, Taxus brevifolia) were derived from medicinal plants.[98][34] The Vinca alkaloids vincristine and vinblastine, used as anti-cancer drugs, were discovered in the 1950s from the Madagascar periwinkle, Catharanthus roseus.

Hundreds of compounds have been identified using ethnobotany, investigating plants used by indigenous peoples for possible medical applications.[100] Some important phytochemicals, including curcumin, epigallocatechin gallate, genistein and resveratrol are pan-assay interference compounds, meaning that in vitro studies of their activity often provide unreliable data. As a result, phytochemicals have frequently proven unsuitable as the lead substances in drug discovery. In the United States over the period 1999 to 2012, despite several hundred applications for new drug status, only two botanical drug candidates had sufficient evidence of medicinal value to be approved by the Food and Drug Administration.

The pharmaceutical industry has remained interested in mining traditional uses of medicinal plants in its drug discovery efforts. Of the 1073 small-molecule drugs approved in the period 1981 to 2010, over half were either directly derived from or inspired by natural substances.