Flavonoids and phenylethanoids from the flowers and leaves of Aeschynanthus species and cultivars (Gesneriaceae).

Forty-one flavones, each one of flavonol, chalcone and dihydroflavonol, two flavanones, and four phenylethanoids were isolated from corollas, calyces and leaves of two Aeschynanthus species, A. fulgens and A. pulcher, and six cultivars, 'Mahligai', 'Mona Lisa', SoeKa', 'Redona', 'Freshya' and 'Bravera'. Flavonoids were mainly the glucuronides and/or methylglucuronides based on hispidulin, nepetin, pectolinarigenin, 6-hydroxyluteolin, scutellarein, apigenin and luteolin, and identified by UV spectra, HR-MS, LC-MS, acid hydrolysis, NMR, and/or HPLC and TLC comparisons with authentic samples. Of these flavonoids, twelve, i.e. hispidulin 7,4'-di-O-glucuronide, 7,4'-di-O-methylglucuronide, 7-O-methylglucuronide-4'-O-glucuronide, 7-O-glucuronide-4'-O-methylglucuronide, 7-O-glucosyl-(1 â†’ 2)-glucuronide and 8-C-glucoside, nepetin 7,4'-di-O-glucuronide, 7-O-glucuronide-4'-O-methylglucuronide and 7-O-methylglucuronide-4'-O-glucuronide, pectolinarigenin 7-O-glucosyl-(1 â†’ 2)-glucuronide and 7-O-xylosyl-(1 â†’ 2)-(6″-malonylglucoside), and 6-hydroxyluteolin 7,4'-di-O-glucuronide, were previously undescribed.

Acylated pelargonidin and cyanidin 3-sambubiosides from the flowers of Aeschynanthus species and cultivars.

Thirteen anthocyanins were isolated from the flowers of two Aeschynanthus species, A. fulgens and A. pulcher, and six cultivars, 'Mahligai', 'Mona Lisa', 'SoeKa', 'Redona', 'Freshya' and 'Bravera', and identified as pelargonidin and cyanidin 3-O-sambubiosides and their malonates, succinates, p-coumarates and caffeates, and pelargonidin 3-O-glucoside by acid hydrolysis, HR-MS and NMR. Of their anthocyanins, pelargonidin 3-O-[xylosyl-(1 â†’ 2)-(6''-malonylglucoside)] (2), pelargonidin 3-O-[xylosyl-(1 â†’ 2)-(6''-succinylglucoside)] (3), pelargonidin 3-O-[xylosyl-(1 â†’ 2)-(6''-E-p-coumaroylglucoside)] (4), pelargonidin 3-O-[xylosyl-(1 â†’ 2)-(6''-Z-p-coumaroylglucoside)] (5), pelargonidin 3-O-[xylosyl-(1 â†’ 2)-(6''-E-caffeoylglucoside)] (6) and cyanidin 3-O-[xylosyl-(1 â†’ 2)-(6''-succinylglucoside)] (9) were reported in nature for the first time.