Direct ingestion method for enhancing production and bioavailability of resveratrol and other phytoalexins in Vitis vinifera.

Phytoalexins such as resveratrol and pterostilbene, produced de novo by many plant species, including grapevine (Vitis vinifera), play a role in plant defense against injury and pathogens. In human cell lines and in animal studies, phytoalexins have been shown to be highly beneficial, with protective effects against cancer, cardiovascular disease, neurodegenerative diseases, diabetes, hyperglycemia, as well as potential effects on longevity. However, in clinical studies, there are multiple factors that restrict this plethora of health benefits attributed to phytoalexins. One of these barriers is rapid metabolism in the intestines and liver. As a means to overcome this barrier, there is evidence that retaining resveratrol in the mouth for extended periods allows for higher plasma levels of resveratrol. Processing, transport or storage may cause degradation due to light and air exposure. When the berries have been picked, they may not be at their peak phytoalexin production due to lack of elicitor induction. To overcome these barriers inherent in phytoalexin production and uptake, it is proposed that berries and possibly the edible leaves be directly ingested off of a grapevine, without harvesting. In addition to the benefit of removing these barriers to potential health benefits, this method introduces a variety of known phytoalexin elicitors, in the form of plant wounding and human saliva, which may enhance the levels of phytoalexins dramatically. The combined effect of multiple phytoalexins may also play a role in enhanced health benefits. To test this hypothesis, experiments with direct ingestion would be performed, followed by testing the participants' plasma levels of resveratrol and potentially other phytoalexins. Proposed variables to be tested include: different subjects, elicitors, cultivars of grapevine, ripeness of fruit, and a range of time for the ingestion process. The potential implications include a direct means of obtaining, in clinically beneficial doses, the tremendous health benefits that have been documented for phytoalexins in vitro and in animal studies, but that have so far remained elusive in clinical studies. This study on direct ingestion may lead to alternative methods for obtaining these clinically beneficial doses.