Free radical scavengers, antioxidants and aldose reductase inhibitors from Camptosorus sibiricus Rupr.

Flavonoids and organic acids were recommended in the literature as the main active constituents of Camptosorus sibiricus Rupr. Assay-guided fractionation led to the isolation of 9 flavonoids and 8 phenolic acids. All compounds were tested for DPPH scavenging activity, SOD-like and aldose reductase inhibition. Among them, compounds 1, 2, 3, 5, 6, 7, 8, 9, 11, 15 showed activities. The most active free radical scavenger and antioxidant was compound 8, while compound 1 exhibited strong inhibiting activity of aldose reductase. The structure-activity relation was dicussed briefly.