Chinese herbal remedies yield anti-cancer drug leads

Medicinal plants used in traditional remedies offer a potential treasure trove of compounds for drug companies looking for the next blockbuster cancer treatment. But, with so many different plants used by healers, it’s been difficult to know which contain the richest supply of possible drug-like molecules. 

Now, scientists have developed a prediction method for finding only the most potent plants. They’ve zeroed in on just 57 plants that could be laden with different anti-cancer compounds from a list of more than 2,400 included in the traditional Chinese medicine (TCM) Database@Taiwan, the world’s largest open repository of traditional Chinese medicines. The database includes details about the relationship between these plants and more than 21,000 pure compounds. 

This diverse group of 57 plants and the compounds they contain “are worthy of further studies and provide more chances for the development of new cancer drugs,” says bioinformatics researcher Shao-Xing Dai from the Chinese Academy of Sciences’ Kunming Institute of Zoology. 

Dai and his colleagues used computational methods to determine which of the thousands of compounds in the TCM Database@Taiwan have anti-cancer potential.  CDRUG is a computational method they developed in 2012 that compares the chemical structure of molecules of unknown activity with those in a large library where the anti-cancer properties of the molecules have been established. Using this method, they honed in on 5,278 compounds with molecular similarities to known anti-cancer drugs and drug candidates. 

Dai’s team then looked for plants that had an abundance of these compounds. Their analysis found 57 plants, each with at least eight compounds with tumour-targeting potential. The jiaogulan climbing vine, Gynostemma pentaphyllum, had the most with 104.  

A literature search revealed that other scientists had previously identified many of these plants as having anti-cancer properties. These included ginseng, red sage, Chinese bellflower, and several other herbs and shrubs. However, 24 of the plants enriched with potential anti-cancer compounds had never been studied extensively before. These newly identified plants, says Dai, offer “a broader scope to mine for potential anti-cancer agents.” 

It’s an approach that has had some success in the past. More than 50 years ago, for example, the chemotherapy drugs vinblastine and vincristine were isolated from the rosy periwinkle plant, a staple of Chinese traditional medicine. Both of these chemotherapeutics are now included on the World Health Organization's List of Essential Medicines, the most important drugs needed in a basic healthcare system. 

Dai and his colleagues’ analysis suggests other plants for investigation for further leads. Their predictive methods could be extended to catalogues of medicinal plants used in other cultures, including traditional Arabic medicine.

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