The astonishing results have been seen in tests on laboratory mice that were given nimbolide pills, which contain an active compound from the neem plant (Azadirachia indica). There were no adverse reactions to the supplement.
Researchers from the National University of Singapore think that nimbolide directly targets an enzyme that plays a key role in the development of prostate cancer.
The neem plant is routinely used in Ayurvedic medicine, the traditional medicine of the Indian sub-continent, and its leaves and bark are often found in many personal care products, including soaps, toothpaste, skincare aids and dietary supplements.
Although other studies have shown that neem has cancer-fighting properties, the researchers say that theirs is one of the first to show the biological mechanisms that are taking place.