Evaluation of the antioxidant activity of grape marc in the peroxidation of mitochondria and microsomes of rat liver

The wine industry in general, as part of the process of making red wine produces a solid by-product called "grape marc" (o grape pomace) which is constituted by seed, skin and grape stalks, which is usually discarded. The grape marc (GM) is a potential source of bioactive phenolic compounds that can be applied as supplement for animal production. Polyphenols from grape-derived products have been associated with the prevention of numerous diseases including cardiovascular diseases, neurodegenerative diseases, as well as several forms of cancers. Grape marc, contains large amounts of polyphenols with antioxidant, anti-inflammatory, antimicrobial, and antiaging effects. The objective of this study was to investigate the antioxidant effect of GM on the peroxidation of hepatic microsomes membranes and hepatic mitochondria. Rat liver microsomes and mitochondria were incubated with different concentrations of GM (25, 50, 100, 200 and 400 mg/ml) in an in vitro non-enzymatic ascorbic acid-Fe⁺² system in order to determine the oxidative effect on membranes and to quantify peroxidation level in standardized conditions. The microsomal peroxidation was quantified in a liquid scintillation counter Packard 1900TR by chemiluminescence in cpm (counts per minute), using microsomal membranes and mitochondria without grape marc as control. Analyzing the effect of GM  was observed that the total cpm/mg protein originated from light emission: chemiluminescence, was statistically lower in samples obtained from GM group than in the control group, the antioxidant effect found was dependent concentration. Finding the greatest protection when we incorporate 100mg of grape marc extract considering both the evaluation of mitochondria and microsomes.

The results of mitochondria samples show the mean and its standard error of the averages of the cpm of the control sample 591±193; of control + ascorbate 1234,7±402 and of different concentrations used of grape marc: 25 mg/ml 862,3±281; 50 mg/ml 493±161 ,100 mg/ml 447,7±146, 200mg/ml 603,3±197 and 400 mg/ml 583,3±190. The results of microsomes samples shows the mean and its standard error of the averages of the cpm of the control sample 547 ±178; of control + ascorbate 1710 ±557 and of different concentrations used of grape marc: 25 mg/ml 1487,7 ±485; 50 mg/ml 787,7 ±257,100 mg/ml 476,3 ±155, 200mg/ml 559,3±182 and 400 mg/ml 678±221. These results indicated that GM may act as antioxidant, protecting rat liver microsomes and mitochondria from peroxidative damage. This is extremely important since it is a very economical by product.