Two new stereoisomeric antioxidant triterpenes from Potentilla fulgens

The roots of Potentilla fulgens have been used for a long time as a folk remedy for many ailments without having information on its pharmacological action. Of the various extracts prepared by partitioning of the methanol extract, the ethyl acetate fraction was found to possess better antioxidant and cytotoxic activities. The degree of reduction in cloning efficiencies of MCF-7 cell lines was more with ethyl acetate than with hexane fraction of the root-extract. Hence, this fraction was further purified and nine compounds, including two new ursane type triterpenoids Fulgic acid A (4) and Fulgic acid B (5), were identified and characterized. Other compounds were identified as ursolic acid, euscaphic acid, corosolic acid, epicatechin, catechin, p-hydroxybenzaldehyde and gallic acid. Chemical structures were elucidated by spectroscopic methods, especially ESIHRMS and 2D NMR techniques. The new compounds showed good antioxidant activity and therefore this plant can be a source of natural antioxidants.