Enrichment of caffeic acid in peanut sprouts and evaluation of its in vitro effectiveness against oxidative stress-induced erythrocyte hemolysis.

The profile of caffeic acid in tissues of peanut sprouts and its antioxidant activity in erythrocyte-based assays were investigated. Caffeic acid was found to accumulate in the epicotyl-plumule (reached 2097.13±96μg/g DW on day 10 after peanut germination). It was purified by semipreparative high-performance liquid chromatography. The purified caffeic acid showed noticeable protective effects on human erythrocytes against 2,2'-azobis-(2-amidinopropane) dihydrochloride (AAPH)-induced hemolysis. It also contributed to maintenance of normal morphological features and inhibited malondialdehyde formation and the lactate dehydrogenase release in erythrocytes under oxidative stress. Further analysis revealed that caffeic acid effectively inhibited AAPH-induced free-radical production and maintained the normal metabolism of the erythrocytic redox system, including superoxide dismutase, glutathione peroxidase, and glutathione. Our work showed that caffeic acid, which is greatly enriched in peanut sprout, can effectively protect erythrocytes from oxidative damage. These results provide valuable information for the use of peanut sprouts as a functional food.