The Chinese herb Scutellaria barbata has been found to slow progression of prostate tumours in mice, suggesting potential chemopreventive effects in humans.
The herb, a species related to mint of the Labiate family, is used in traditional Chinese medicine to treat several illnesses, including cancers of the liver, lung and rectum. A new study presented yesterday by researchers from Union College in Nebraska found it could offer hope against the second leading cause of cancer deaths among American men.
The researchers used transgenic adenocarcinoma of the mouse prostate (TRAMP), which mimics tumour progression in human prostate cancer, providing a relevant pre-clinical model.
"We are finding that, in this case, the therapeutic value of natural herbs is presenting itself as clinically valid," said Dr Brian Wong of Union College, lead author of the study.
"As we further study Scutellaria barbata, we hope to find the same benefits against prostate cancer in human models," he added.
In the study, researchers determined the extent of apoptosis (cell death) and necrosis (tissue death), as well as palpable tumour formation. Results of culturing the cancer cells with SB for two hours suggested that two hours is the optimal incubation time for SB to induce apoptosis in TRAMP-C1 cells.
Mice were fed daily in random groups, either receiving sterile water as placebo or experimental doses of 8 milligrams and 16 milligrams of sterile SB aqueous extracts.
In the placebo group, palpable tumours developed at 19 weeks of age, and by 32 weeks, all of the mice had palpable tumours. By comparison, 20 per cent and 30 per cent of the mice in the 8mg and 16mg SB groups, respectively, were free of tumours. At 27 weeks, fewer than 30 per cent of the placebo animals were free of palpable tumours; in the low- and high-dose groups, 50 per cent and 70 per cent of the mice were tumour-free.
The data demonstrates that SB contains phytochemicals that modulate apoptosis of the TRAMP mouse prostate cancer cells in vitro and delay tumour development in vivo.
The most recent research data demonstrated that SB has a similar effect in the induction of apoptosis in a human prostate cancer cell line, LNCaP (lymph node carcinoma of the prostate), and also modulates the PARP (Poly ADP-Ribose Polymerase, an enzyme required for the detection of DNA strand interruptions) of the same cell line.
This research was presented at the Frontiers in Cancer Prevention Research meeting in the US this week. Yesterday we reported on another study investigating diet and prostate cancer prevention, which appeared to challenge previous advice for prostate cancer patients to reduce fat intake to prevent progression of the disease. Lowering carbohydrate intake could be more effective, it was found.