Naphthofuranone derivatives and other constituents from Pachira aquatica with inhibitory activity on superoxide anion generation by neutrophils

Two new naphthofuranone derivatives, 11-hydroxy-2-O-methylhibiscolactone A (1) and O-methylhibiscone D (2), have been isolated from the stems of Pachira aquatica, together with 18 known compounds (3 − 20). The structures of two new compounds were determined through spectroscopic and MS analyses. Among the isolated compounds, 11-hydroxy-2-O-methylhibiscolactone A (1), isohemigossylic acid lactone-7-methyl ether (4), gmelofuran (6), and 5-hydroxyauranetin (8) exhibited inhibition (IC₅₀ ≤ 28.84 μM) of superoxide anion generation by human neutrophils in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP).