Study on Chemical Constituents of Lonicera japonica Bud

Objective To study the chemical constituents of Lonicera japonica bud. Methods The compounds were isolated and repeatedly purified by silica gel column chromatography, gel column chromatography and ODS chromatography. The structures were elucidated by physicochemical properties, MS and NMR. Results Eight compounds were isolated and their structures were identified as protocatechuic acid (1), 5-hydroxy-7,3',4'-trimethoxyflavone (2), hyperoside (3), 4-hydroxycinnamic acid (4), ethyl caffeate(5), apigenin (6), 5-hydroxy-6,7,8,4'-tetramethoxyflavone (7), and ethyl laurate (8). Conclusion Compounds 5, 7 and 8 are obtained from this genus for the first time.