Chemical Constituents and Antimicrobial Properties of the Nonresinous Heartwood of Aquilaria sinensis

Abstract

Twenty-six compounds, including one new 2-(2-phenylethyl)chromone derivative, (R)-2-(1-hydroxy-2- phenylethyl)chromone (1), and one new resorcylic acid lactone, (S)-de-O-methylhispidulactone A (2), were isolated from the nonresinous heartwood of Aqualaria sinensis (Lour.) Spreng. Among these compounds, (S)-de-O-methylhispidulactone A (2), 2-(2-phenylethyl)chromone (4), 2-[2-(4-hydroxyphenyl)ethyl]chromone (7), 6-methoxy-2-(2-phenylethyl)chromone (8), 6-methoxy-2-[2-(3-methoxyphenyl)ethyl]chromone (9), 2-[2-(3-methoxyphenyl)ethyl]chromone (10), 6,7-dimethoxy-2-(2-phenylethyl)chromone (11), 8-chloro-6- hydroxy-2-[2-(4-methoxyphenyl)ethyl]chromon-4-one (13), (+)-(R)-de-O-methyllasiodiplodin (14), lasiodiplodin (15), and (3R)-(–)-melliein (20) exhibited antifungal activity against Epidermophyton floccosum, Trichophyton rubrum, and Microsporum gypseum, with MIC values ranging from 5.8 to 51.6 μM. Furthermore, (R)-2-(2-hydroxy-2-phenylethyl)chromone (3b), 7, 8, 9, 14, 15, 5-hydroxy-7,3′,4′- trimethoxyflavone (17), and velutin (18) demonstrated antibacterial effects against Staphylococcus aureus, with MIC values ranging from 20.2 to 96.0 μM.