Three new biflavonoids from the branches and leaves of Cephalotaxus oliveri and their antioxidant activity

Abstract

Three new biflavonoids, named oliveriflavones A-C (1–3), together with two known flavonoids (quercetin (4) and rutin (5)), were isolated from the endangered plant Cephalotaxus oliveri. The chemical structures of these compounds were elucidated by comprehensive spectroscopic methods including NMR, HRESIMS, IR, UV, and CD spectra. Compounds 1–5 were first isolated from the genus Cephalotaxus. All the compounds were tested for their antioxidant activity. Compounds 4 and 5 showed excellent activity with IC₅₀ values of 0.03 ± 0.06 μM and 0.02 ± 0.10 μM, respectively.

Keywords:

• Cephalotaxus oliveri
• biflavonoid
• antioxidant activity

Acknowledgement

The authors thank Dr. Shou-Feng Wang in the NMR group in Analytical and Testing Center for his kind advices and help.