New drugs based on plants

© Shutterstock
© Shutterstock
In the past decade, two botanical drugs have been approved by the FDA. This opens a new area for the elaboration of drugs by pharmaceutical industries. Indeed, regulation authorities usually are very strict about marketing authorization and up to recently, were putting a brake to the elaboration of Botanical drugs.

 

Even though plants have been used as model for the elaboration of drugs such as Taxol or Aspirin, not every compound presents such a specific effect on a specific target. One plant usually produces a lot of metabolites such as terpenes or polyphenols that are present under numerous isomers. Therefore, a positive effect on human health that is reported from a plant extract cannot be easily related to one specific compound. The synergistic effects of plant extract that can be observed on certain disease gave way to the elaboration of new drugs that, instead of being the results of one active compound, are the result of a botanical mixture.

For the first time in 2006, a botanical mixture was approved as a drug for prescription use in the United States by the U.S Food and Drug Administration (FDA). This botanical mixture sold under the name of VEREGEN® (sinecatechins) Ointment, 15% consists of an extract from green tea leaves (Camellia sinensis) and is prescribed for external use only to patients suffering from external genital and perianal warts also called Condylomata acuminata caused by the Human Papillomavirus (HPV).

On December 31st 2012, a second botanical drug derived from the red latex of Dragon’s blood (Croton lechleri), FULYZAQ™ (Crofelemer) 125mg, oral use, have been approved by the FDA for the treatment of diarrhea symptoms in HIV/AIDS patients undergoing an antiretroviral therapy.

Botanical drug versus dietary supplements

In order to be approved as a drug by the FDA, a botanical mixture must undergo the following criteria: “A botanical drug product is intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease in humans. A botanical drug product consists of vegetable materials, which may include plant materials, algae, macroscopic fungi, or combinations […] Botanical drug products often have unique features, for example, complex mixtures, lack of a distinct active ingredient, and substantial prior human use. Fermentation products and highly purified or chemically modified botanical substances are not considered botanical drug products”©FDA. This definition contrasts with dietary supplements which cannot be claiming to cure or prevent diseases.

To be approved as a drug, the botanical mixture requires a standardization of the products and clinical tests in order to assess a specific effect on a specific disease. The production of such drugs is therefore more complicated and makes it more difficult than chemical drugs. However, the elaboration of specific extraction processes and the ability to control the production of the plant material make possible the production of a standard drug. In the case of crofelemer, it is interesting to know that in order to ensure sustainability of the plant material, Napo Pharmaceuticals Inc. the producer of the compound is controlling Croton lechleri tree population by itself.

A promising future

The future of botanical drugs is very promising. Indeed as many new ethnobotanical studies are being made all over the world since a few decades, the discovery of new plants for the treatment of diseases is a potential growing market. Many plant based drugs have been authorized for clinical trials and over a hundred plant derived compounds are undergoing clinical trials for anticancer activities, antibiotic activities or antiviral activities. On April 2014, Merck & Co’s GRASTEK®, a standardized extract from the pollen of Phleum pretense, received the FDA approval for the treatment of hay fever.

The market of botanical drug is more likely expected to increase in the coming years as more natural plant compounds are being characterized and are showing effectiveness in the treatment of a various types of diseases.


 

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