Neem inhibits prostate cancer

A new study has found that consumption of the bioactive compound nimbolide, derived from the leaves of the neem plant, could significantly suppress thedevelopment of prostate cancer. The findings were published in Antioxidants & Redox Signaling in April 2016.

Prostate cancer is one of the most commonly diagnosed cancers in the world. However, current therapies are only marginally effective.

This latest study by Associate Professor Gautam Sethi from the Department of Pharmacology at NUS Medicine, in collaboration with Professor Goh Boon Cher of the Cancer Science Institute of Singapore at NUS, Professor Hui Kam Man of the National Cancer Centre Singapore and Professor Ahn Kwang Seok of Kyung Hee University in Korea, found that oral administration of nimbolide can suppress cell invasion and migration of prostate cancer cells without any significant adverse effects. Over a period of 12 weeks, tumour size was reduced by up to 70 per cent and its metastasis, or spread, by up to 50 per cent.

The nimbolide works by targeting glutathione reductase, an enzyme responsible for maintaining the antioxidant system that regulates the STAT3 gene in the body. This then inhibits STAT3 activation, which has been reported to contribute to prostate tumour growth and metastasis.  

“In this research, we have demonstrated that nimbolide can inhibit tumour cell viability — a cellular process that directly affects the ability of a cell to proliferate, grow, divide, or repair damaged cell components — and induce programmed cell death in prostate cancer cells," said Assoc Prof Sethi.

NUS Pharmacology team members (from left): Research Fellow Dr Muthu K Shanmugam, first author PhD student Zhang Jingwen and Assoc Prof Sethi

Although the anticancer effects of nimbolide have been observed in breast, colon and oral cancer studies, this is the first time its potential effects on prostate cancer initiation and progression have been proven.

Originally native to India and the Indian sub-continent, the neem plant — part of the mahogany tree family — is commonly found in Singapore. It has been used in traditional Asian medicine for centuries and can also be found in soaps, toothpaste, skincare products and dietary supplements.

The team plans to conduct further studies into the side effects of nimbolide, other potential molecular targets, as well as the efficacy of nimbolide when combined with other drugs for prostate cancer therapy. 

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