The findings of two recent studies illuminate the cancer-fighting properties of resveratrol, a phytochemical found in red wine, grape skins, purple grape juice, peanuts, and some berries.

One set of investigators found that resveratrol remains effective once it has been metabolized. Whereas the compound has been shown to exert numerous health benefits in preclinical studies, its rapid metabolism and poor bioavailability could limit translation of these effects to humans, explained a team led by Professor Karen Brown, a translational cancer researcher at the University of Leicester in Leicester, United Kingdom, in Science Translational Medicine (2013;5[205]:205ra133).

Brown and colleagues were able to detect free resveratrol in the plasma and various tissues of mice that had been given resveratrol sulfate. As summarized in a statement from the University of Leicester, this is the first direct sign that resveratrol can be formed from resveratrol sulfate in live animals.

The free resveratrol generated from the resveratrol sulfate was able to induce autophagy (controlled digestion of damaged organelles within a cell) in cancer cells and stop them from dividing. The investigators pointed out that at doses considered to be safe in humans, metabolized resveratrol may be of greater importance than the unmetabolized form.

Data from a separate study reported in Journal of Surgical Research (2013;183[2]:645-653) suggested that resveratrol enhances the sensitivity of melanoma cells to radiation therapy by inhibiting proliferation and promoting apoptosis (programmed cell death) of the cancer cells. Similar results had been seen in previous research involving prostate cancer cells.

Michael Nicholl, MD, a surgical oncologist at the University of Missouri’s Ellis Fischel Cancer Center in Columbia, Missouri, and associates learned that adding resveratrol to melanoma cells made the cells more susceptible to the effects of radiation: After the addition of resveratrol alone, 44% of the tumor cells were destroyed; the combination of resveratrol plus radiation destroyed 65% of the cells.