Toxic herb ‘lei gong teng’ can limit tumour growth



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February 17, 2007  
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CM NEWS – A substance in traditional Chinese herb lei gong teng (???, Tripterygium wilfordii Hook. f., Radix Tripterygium wilfordii, three-wing-nut) is found to be effective in prohibiting tumour growth in colon cancer and leukemia patients, according to a recently published study completed by the Institute of Hematologic Disease at Zhejiang University, China.

Triptolide (??????, ?????; extract of lei gong teng), a traditional Chinese medicine, has been reported to be effective in the treatment of autoimmune diseases and exerting antineoplastic activity in several human tumour cell lines. Lei gong teng has been used hundreds of years in Chinese medicine for treating arthritis. Scientists have been interested in its anti-tumour effect in recent years.

In one study, using triptolide on leukemia mice has prolonged survival rates to as high as 158%. Other studies have shown that triptolide can also inhibit cancer cells of the stomach, by causing the cancer cells to destroy themselves. As much as half of the cancer cells died off in just two days.

Studies done at the University of Hong Kong on arthritis have found that triptolide can prohibit the activities of ultra-active immune cells that cause arthritis, and can inhibit the T-cells from growing and populating. Leader investigator Liu Zexing (???) said the function of triptolide seems not to be kiling the undesirable cells, but to induce them to die in a natural way.

Lei gong teng is also famous for its high toxidity.

In the present study done in Zhejiang University, scientists investigated the antitumour effect of triptolide in human colon cancer cells and myelocytic leukemia. Results showed that triptolide inhibited the proliferation of both tumour cell lines in a dose-dependent manner.

The results suggested that the cancer-fighting characteristics of triptolide might have been achieved through strongly inhibiting an inflammatory enzyme and lowering the activity of inducible nitric oxide synthase gene (iNOS).

How does this work? By regulating the expression of the inducible nitric oxide synthase gene (iNOS), macrophages (large white blood cells) can kill tumour cells by releasing high levels of nitric oxide (NO) and related reactive nitrogen species such as nitroxyl and peroxynitrite.

What is COX? Cyclooxygenase (COX) is an enzyme that is responsible for formation of important biological mediators called prostanoids (including prostaglandins, prostacyclin and thromboxane). Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain; this is the method of action of well-known drugs such as aspirin and ibuprofen.

[Acta Biochim Biophys Sin (Shanghai). 2007 Feb;39(2):89-95.]