Antioxidant activity of three extracts of Morus nigra.

The antioxidant effect of three different extracts of Morus nigra fruit (fruit juice, hydroalcoholic and polyphenolic) on haemoglobin glycosylation, peroxidative damage to human erythrocytes, liver hepatooytes of rats and human low-density lipoprotein (LDL) were studied. The results show that all three extracts inhibited haemoglobin glycosylation induced by glucose to differing degrees. The haemolysis of human erythrocytes induced by hydrogen peroxide was also inhibited. The production of malondialdehyde (MDA) during peroxidative damage to plasma membranes of isolated rat hepatocytes induced by tert-butyl hydroperoxide (tBH) was also inhibited. Inhibition of lipid peroxidation of LDL induced by copper (II) ion was achieved during the study. The results suggest that Morus nigra fruit has a protective action against peroxidative damage to biomembranes and biomolecules. Copyright 2004 John Wiley & Sons, Ltd.