First Chemical Constituents from Cordia exaltata Lam and Antimicrobial Activity of Two Neolignans

Abstract

The phytochemical study of Cordia exaltata Lam. (Boraginaceae) led to the isolation, through chromatographic techniques, of nineteen secondary metabolites: 8,8'dimethyl-3,4,3',4'-dimethylenedioxy-7-oxo-2,7'cyclolignan (1), 8,8'-dimethyl-4,5-dimethoxy-3',4'-methylenodioxy-7-oxo-2,7'cyclolignan (2), sitosterol (3a), stigmasterol (3b), sitosterol-3-O-β-D-glucopyranoside (4a), stigmasterol-3-O-β-D-glucopyranoside (4b), phaeophytin A (5), 13²-hydroxyphaeophytin A (6), 17³-ethoxypheophorbide A (7), 13²-hydroxy-17³-ethoxypheophorbide A (8), m-methoxy-p-hydroxybenzaldehyde (9), (E)-7-(3,4-dihydroxyphenyl)-7-propenoic acid (10), 1-benzopyran-2-one (11), 7-hydroxy-1-benzopyran-2-one (12), 2,5-bis-(3',4'-methylenedioxiphenyl)-3,4-dimethyltetrahydrofuran (13), 3,4,5,3',5'-pentamethoxy-1'-allyl-8.O.4'-neolignan (14), 3,5,7,3',4'-pentahydroxyflavonol (15), 5,7-dihydroxy-4'-methoxyflavone (16), 5,8-dihydroxy-7,4'-dimethoxyflavone (17), kaempherol 3-O-β-D-glucosyl-6''-α-L-ramnopyranoside (18) and kaempherol 3,7-di-O-α-L-ramnopyranoside (19). Their structures were identified by ¹H and ¹³C-NMR using one and two-dimensional techniques. In addition, the antimicrobial activity of compounds 1, 2, 13 and 14 against bacteria and fungi are reported here for the first time.