Antioxidant Profile and in Vitro Cardiac Radical-Scavenging versus Pro-oxidant Effects of Commercial Red Grape Juices (Vitis vinifera L. cv. Aglianico N.)

Several works have reported on the pharmaceutical usefulness of grape phytochemicals. Nevertheless, the scientific literature needs further studies to consider grape extracts as useful dietary supplements. The aim of the present work was to hypothesize for the first time the use of whole commercial red grape juices as food supplements potentially useful against both physiological and induced cardiac oxidative stress. First of all, the results indicated a good antioxidant stability of the juice sample to lyophilization that may be reasonably regarded as a suitable process for the formulation of food supplements. Then, the processed sample (lioRGJ) was tested on cardiac-derived H9C2 myocytes to ascertain its effects on reactive oxygen species (ROS) generation and caspase-3 activity incubating cardiomyocytes with lioRGJ at increasing doses (0.01-1 mu g). Experiments showed an appreciable direct radical-scavenging activity at a maximum sample dose of 0.01 mu g that made the caspase-3 activity decrease by about 47% (P < 0.001). Cardiac cells were exposed to 1 mu M doxorubicin and its combination with different doses of lioRGJ. A maximum sample aliquot of 0.01 mu g seemed to effectively contrast the induced oxidant injury, decreasing the ROS levels by about 31% and depressing the caspase-3 activity by about 60% (P < 0.001). In both assays, pro-oxidant effects at higher sample concentrations were detected as indicated by the increase in both ROS generation and apoptotic activity. The data suggested the possible employment of the juice sample as a food supplement with prospective cardioprotective benefits, although further studies are needed to optimize its dosages to avoid harmful pro-oxidant effects.