Abstract:The monomer and dimer of proanthocyanidins in grape seeds were obtained by gradient and enzymatic extraction, isolation with macroporous adsorption resin, and purification by TLC. The results showed that the optimum extraction conditions were as follows: 60% ethanol (1:7 w/v), at 50 ℃ and 3 times (30 min/time). The extraction ratios of proanthocyanidins in gradient extractions were (7.7341~281.494) mg/100 g grape seeds and highest content of proanthocyanidins was achieved using the ethyl acetate as extraction reagent followed by acetone, ethanol and ether. The free-radical scavenging effect of the ethanol extracts was higher (with the inhibitory ratio being of 85.13%) than those of ether extracts (77.60%) and ethyl acetate extracts (48.64%)(conc.0.004 g/mL). High content of oligometic proanthocyanidins isolated by macroporous adsorption resinwere was achived using 40% ethanol. After purification with TLC ( elution system: toluene/acetone/acetic acid=2/2/1), the yields of monomer and dimmer in ethyl acetate and ether components were 33.25%, 60.64% and 16.23%, 10.13%, respectively.
