Flavonoid from the aerial parts of Cardiospermum halicacabum L

The first chemical investigation on Cardiospermum halicacabum L. growing in Vietnam led to the isolation and structural determination of nine flavonoid compounds, including quercetin 3-O-β-D-glucoside (1), quercetin 3-O-α-L-rhamnoside (2), quercetin (3), kaempferol 3-O-α-L-rhamnoside (4), kaempferol (5), apigenin 7-O-β-D-glucuronide butyl ester (6), apigenin 7-O-β-D-glucuronide methyl ester (7), apigenin (8), and luteolin (9). Their structures were established by using HR ESI MS, 1D and 2D NMR spectroscopic methods and comparison with those of the related published data. With exceptions to flavonoids 3 and 8, the rest seven compounds (1-2, 4-7, and 9) were found for the first time from this plant. Notably, two rare flavonoids (6 and 7) have not yet been reported from the Sapindaceae family before.