Phytodrugs and the mysteries behind medicinal plants

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Human Genetics Scientist, Joyce El Hokayem examines the benefits phytomedicine could offer to today’s healthcare systems and the challenges researchers in this market face

Traditional Chinese medicine has evolved as a system of medical practice from ancient China more than 2000 years ago based on empirical knowledge as well as theories and approaches which are so far to be mapped by scientific equivalents.

The usage of traditional Chinese medicine has developed greatly from its origins and the recognition of its therapeutic benefits has spread worldwide. Despite this the general western medicine community has not fully approved of it due to the lack of clinical trial verification.

Various trends over the past few years have driven the demand for natural herbal remedies .  Research has valued the Global Herbal Medicine market at $111 billion by the end of 2023.  The World Health Organization (WHO) estimates suggest that almost 80% of the populations of many Asian and African countries rely on herbal medicine. Similarly, there are many active ingredients from plants that are used within today’s pharmaceuticals.

Development of a phytodrug

The development of plant drugs start with various analytical methodologies: the extraction, isolation, purification and characterization of active ingredients in botanicals and herbal preparations.

In order to use the biological compound from plant resources, additional steps are required such as pharmacological screening, toxicology and clinical evaluation.

Herbal medicines include: herbs, herbal materials, herbal preparations and herbal products containing either different parts of plants or other plant materials as active ingredients. Herbal plants and their derivatives are well known to play important roles in modern drug development.

Nobel prize winner and Chinese pharmacologist Mrs Youyou Tu discovered and developed Artemisinin – a new herbal drug to combat a parasite that causes malaria - Plasmodium falciparum. The drug was sourced from Artemisia annua, a sweet warmwood plant from China.

Camptotheca acuminate produces Topotecan and Irinotecan which are considered as anticancer agents and have been applied to treat ovarian and small cell lung cancers.

plant medicine

Challenges

Although drug development research from medicinal plants over the past 30 years has succeeded, there are still many challenges to deal with.

The quality of herbal products is often questioned and the standardization of raw material appears as an important issue for herbal industry. Herbal plants can be easily contaminated during growth, processing and collection. The two most important problems that have been reported in herbal medicines are adulteration and heavy metal contamination.

Medical herbal preparations do contain various types of bioactive compounds that are difficult to separate and determinate because of the complexity of the component mixture. Most of these components must be purified by several purification methods in order to isolate the bioactive compounds.

There are many issues encompassing the efficiency and the safety of the use of traditional Chinese medicine in modern society. 

For this reason, it is necessary to improve the quality and quantity of bioactive compounds for new herbal drugs to keep pace with other drug discovery efforts [6].

Currently, there are several medicinal plants which have had their bioactive agents scientifically and clinically evaluated by investigators.

Medications derived from plant sources include the likes of quinine, digoxin, aspirin, ephedrine, atropine and colchicine.

Case study

Scientists at the university of British Columbia published a recent discovery in August 2017 regarding whether red sage (Dan Shen, in traditional Chinese herbal medicine) could help prevent bone loss without inducing any severe side effects.

They could block Cathepsin K (CatK) known as the major bone collagen degrading protease in osteoclast. The potent cathepsin K (CatK) inhibitor, Tanshinone IIA sulfonic sodium (T06), is one of about 60 tanshinone- related compounds found in Salvia miltiorrhiza, also known as Dan shen which is also used as an herbal medicine to treat cardiovascular disorders such as atherosclerosis, stroke, and hyperlipidemia  and skeletal diseases such as arthritis and osteoporosis. Besides, another recent study has shown antiresorptive efficacy in ovariectomized mice (OVX) and rats by using an herbal formulae containing Salvia miltiorrhiza [7].

New technology

There is an important need to improve research for the development and characterization of new natural drugs with the support of new technologies (genome and transcriptome sequencing, metabolite detection at cellular and subcellular level).

With the advancement of technology and research tools, constant efforts must be applied while researching toxicities and the drug interacting potential of herbs including correlation of laboratory findings with clinical studies. Plant biology will face new challenges in nutrition, health, agriculture and energy.

Plants maintain life and could well be the key to discovering and develop new medicines resources.  With this in mind, teamwork with evidence-based medicine is needed to accelerate efforts to control the chemical resources of the plant sphere.

 

References
1.    Bottcher H.  Miracle drugs. Zagreb: Zora; 1965. pp. 23–139.
2.    Wiart C.  Etnopharmacology of medicinal plants. New Jersey: Humana Press; 2006. pp. 1–50
3.    World Health Organisation Media Centre, Traditional Medicine, 2008. 

4.     Heinrich M. Ethnobotany and its role in drug development, Phytotherapy Res. 2000; 14(7):479-488.
5.     Shakya AK, Sharma N, Saxena M, Shrivastava S, Shukla S. Evaluation of the antioxidant and hepatoprotective effect of Majoon-e-Dabeed-ul-ward against carbon tetrachloride induced liver injury. Experimental Toxicology and Pathology. 2012; 64(7-8):767-73.
6.    Dash B, Sharma BK. Charak Samhita. 7th ed. Varanasi (India): Chaukhamba Sanskrit Series, 2001.
7.    57. Cui L, Wu T, Liu YY, Deng YF, Al CM, Chen HQ. Tanshinone prevents cancellous bone loss induced by ovariectomy in rats. Acta Pharmacol Sin. 2004;25(5):678–84.
8.    Torres, María P. et. Graviola: A novel promising natural-derived drug that inhibits tumorigenicity and metastasis of pancreatic cancer cells in vitro and in vivo through altering cell metabolism, Cancer Lett. 2012 October 1; 323(1): 29–40. doi:10.1016/j.canlet.2012.03.031.
9.     Taylor, L. Herbal Secrets of the Rainforest. 2. Sage Press, Inc; 2002. Technical Data Report for Graviola: Annona Muricata.

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