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