Flavanones of Erythrina livingstoniana with antioxidant properties.

Six new flavanones (1-6), together with six known compounds were isolated from Erythrina livingstoniana. Their structures were elucidated on the basis of NMR data and HRMS(n) fragmentation pathway and by comparison with literature data. Compounds 5, 7 and 8 showed remarkable DPPH free radical scavenging efficacies. The compounds, however, did not demonstrate an anti-inflammatory potential when tested using a PGE2 (prostaglandin E2) competitive enzyme immunoassay. The plausible biosynthetic pathways of the isolated compounds are described.