Proanthocyanidins from Ginkgo biloba leaf extract and their radical scavenging activity

Figures & data

Figure 1.  Chemical structures of the isolated compounds from Ginkgo biloba leaves.

Table 1.  Radical scavenging activities of the crude extract, the positive control [butylated hydroxytoluene (BHT)] and the isolated compounds 1–7 against DPPH.

Compounds or extract	IC50 (µg/mL)^a
Crude extract (CE)	15.5 ± 0.20
Catechin (compound 1)	6.3 ± 0.12
Epigallocatechin (compound 2)	3.8 ± 0.15
Gallocatechin (compound 3)	3.8 ± 0.13
Epigallocatechin-(4β→8)-catechin (compound 4)	4.9 ± 0.12
Epigallocatechin-(4β→6)-catechin (compound 5)	4.7 ± 0.11
Epigallocatechin-(4β→8)-epigallocatechin (compound 6)	1.7 ± 0.10**
Epigallocatechin-(4β→8)-epigallocatechin-(4β→8)-catechin (compound 7)	2.1 ± 0.10**
BHT	17.3 ± 0.40

^aValues are means ± data obtained from three different assays.

**P < 0.001 compared with positive control.