Chemical Constituents from the Branches and Leaves of Chimonanthus praecox with Antiviral Activity Investigations

Ten compounds were isolated from the branches and leaves of Chimonanthus praecox by various chromatographic techniques.By spectroscopic methods,their structures were elucidated as(+)-calycanthine(1),(-)-folicanthine(2),(-)-chimonanthine(3),isofraxidin(4),3,3'-biisofraxidin(5),euoniside(6),kaempferol-3-O-rutinoside(7),3,4-dihydroxybenzonitrile(8),di-O-methylcrenatin(9) and acanthoside B(10).Among them,compounds 4-10 were obtained from the herb for the first time.The inhibitory activity of compounds 1-5 and 8 against porcine respiratory and reproductive syndrome virus(PRRSV) was measured by the cytopathic effect(CPE) method.Compounds 2(IC50 = 58.9 ± 10.2 μM;TI = 19.3),3(IC50 = 68.9 ± 3.1 μM;TI = 17.9) and 8(IC50 = 80.5 ± 16.9 μM;TI 19.9) showed weak effect on PRRSV.