Flavonoids from the Seeds of Hovenia acerba and Their In vitro Antiviral Activity

A new flavonoid, 6??-acetyl-spinosin (12), together with 14 known flavonoids, were isolated from Hovenia acerba. Their structures were elucidated by extensive spectroscopic methods. The rotamers of four flavonoid C-glycosides 12–15 was investigated for the first time. All the flavonoids were evaluated for their anti-RSV activity by cytopathic effect (CPE) reduction assay. As a result, five flavonoids, 3, 7, 10, 13, and 14, displayed better antiviral effect against three RSV strains. Plaque reduction assay demonstrated that compound 13 mainly inhibited the intracellular replication of RSV. HPLC analysis indicated that the active compounds 3, 7, and 13 had higher contents in the seeds.