Antioxidant activity of proanthocyanidins from adansonia digitata fruit

Besides（-）-epicatechin,epicatechin-（4β-8 ）-epicatechin（procyanidin B2）,epicatechin-（4β-6 ）-epicatechin （procyanidin B5）,epicatechin-（4β-8,2β-O-7）-epicatechin（proanthocyanidin A2） and epicatechin- （4β-8）-epicatechin-（4β-8）-epicatechin（procyanidin C1）,which were isolated before from Adansonia digitata, in this work an A-type proanthocyanidin trimer,i.e.epicatechin-（4β-8）-epicatechin-（4β-8,2β-0-7）- epicatechin,tetrameric procyanidin D1,i.e.epicatechin-（4β-8）-epicatechin-（4β-8）-epicatechin-（4β-8）- epicatechin and a polymeric compound were isolated from the pericarp（fruit wall） of the fruits for the first time from this plant.The antioxidant activity of different fractions and pure compounds was experimentally evaluated in the DPPH- assay.The ethyl acetate fraction,and most of the isolated compounds displayed a high activity(IC50 2.40-9.60μg/ml) compared with the reference antioxidant Trolox(IC50 12.18μg/ml) as a standard.