Antioxidant activity and radioprotective effects against chromosomal damage induced in vivo by X-rays of flavan-3-ols (Procyanidins) from grape seeds(Vitis vinifera): Comparative study versus other phenolic and organic compounds

The quantitative distribution of several flavan-3-ols was determined using HPLC in a grape (Vitis vinifera) seed extract (GSE) of four cultivars grown In the region of Murcia. Polymer greater than or equal to C-4 units made u p the largest group of procyanidins in the GSE (90.92%, expressed as HBLC % area). The antioxidant activity of GSE and other reference compounds was i nvestigated by measuring their ability to scavenge the ABTS(.)+ radical cat ion (TEAC). The most effective compounds were, in order: GSE > rutin > (+) -catechin > diosmin greater than or equal to ascorbic acid. The radioprotec tive effects of GSE and other reference compounds were determined by using the micronucleus test for anticlastogenic activity, any reduction of the fr equency of micronucleated polychromatic erythrocytes (MnPCEs) being evaluat ed in the bone marrow of mouse exposed to X-rays. The most effective compou nds were, in order: GSE > rutin > dimethyl sulfoxide (DMSO) > ascorbic acid > 6-n-propyl-2-thiouracil-6c (PTU) > diosmin. The higher ABTS(.)+ scavengi ng capacity and anticlastogenic activity of GSE can be explained, structura lly, by the high number of conjugated structures between the catechol group s in the B-rings and the 3-OH free groups of the polymeric polyphenolic ske leton and, in addition, by the stability of the aroxyl flavonoid radical ge nerated in the above processes.