Chemical constituents of Lobelia chinensis / 中草药

ABSTRACT

Objective: To investigate the chemical constituents in the dried whole plant of Lobelia chinensis. Methods: Column chromatography, such as silica gel, MCI, ODS, Sephadex LH-20, C18 reverse-phased silica gel columns, and preparative HPLC were used to isolate the compounds. Spectroscopic methods like MS, 1H-NMR, and 13C-NMR were used to elucidate their structures. Results: Fifteen compounds were isolated from 95% ethanol extract of L. chinensis, including twelve flavonoids: quercetin (1), rutin (2), luteolin (3), apigenin (4), hesperidin (5), quercetin-3-O-α-L-rhamnoside (6), quercetin-7-O-α-L-rhamnoside (7), quercetin-3- O-β-D-glucoside (8), amentoflavone (9), naringenin (10), hesperetin (11), and eupafolin (12), and three coumarins: 5, 7- dimethoxy-coumarin (13), isoscopoletin (14), and scoparone (15). Conclusion: Compounds 6-12 are isolated from the plants in genus Lobelia L. for the first time. Compounds 5, 13, and 14 are isolated from L. chinensis for the first time.