Studies on free radical scavenging activities of extracts from fresh leaves of some Gymnosperms

A DPPHMicroplate assay were made to determine the free radical scavenging activity of the 80% methanol extracts from the leaves of some Gymnosperms.The results revealed that different genera and species have very different free radical scavenging capacities,and as the raising of concentration and the prolonging of incubation time at 37℃,their free radical scavenging capacities increased.Among all the trees tested,Podocarpus macrophyllus (Thunb.) D.Don,Chamaecyparis obtusa cv.tetragona,Podocarpus brevifolius (Stapf) Foxw,Pinus elliottii Engelm.,Cunninghamia lanceolata (Lamb.) Hook.f,and Juniperus formosana Hayata showed the strongest free radical scavenging capacity,the extracts at a concentration that equals to 0.5 mg leaves per milliliter and after incubating for 20 min,their scavenging rates to 1 mmol/L DPPH were 61.1%,58.4%,57.6%,57.1%,51.8% and 50.4%,respectively.