Objective: To study the antiviral constituents in the stems and leaves of Pithecellibium clypearia.
Method: The constituents of P. clypearia were systematically separated with various chromatographic techniques in combination with antiviral activity monitoring. Their structures were elucidated by physical and chemical properties and spectral data.
Result: Six compounds were isolated from P. clypearia and were identified as: tricetiflavan (5, 7, 3', 4', 5'-pentahydroxylflavan) (1), myricitrin (myricetin-3-O-alpha-L-rhamnopyranoside) (2), quercitrin (quercetin-3-O-alpha-L-rhamnopyranoside) (3), quereetin (4), methyl gallate (5) and gallic acid (6).
Conclusion: Compound 1 approximately 5 were obtained from this plant for the first time. Compound 4 was found to show an obvious anti-respiratory syncytial virus (RSV) activity.