Two auronols from Pseudolarix amabilis

Two new auronols, amaronols A (1) and B (2), were isolated from the bark of Pseudolarix amabilis, along with pseudolaric acid B (3), pseudolaric acid C (4), demethoxydeacetaxy-pseudolaric acid B (5), pseudolaric acid B-beta-D-glucoside (6), pseudolaric acid A-beta-D-glucoside (7), and myricetin (8). The structures of amaronols A and B were established by spectral data interpretation as 2,4,6-trihydroxy-2-[(3',4',5'-trihydroxyphenyl) methyl]-3(2H)-benzofuranone and 2,4,6-trihydroxy-2-[(3',5'-dihydroxy-4'-methoxyphenyl) methyl]-3(2H)-benzofuranone, respectively. Antimicrobial testing results of the eight compounds indicated that only pseudolaric acid B was active against Candida albicans (MIC, 3.125 mu g/mL; MFC, 6.25 mu g/mL), while myricetin was marginally active against Trichophyton mentagrophytes (MIC, 50 mu g/mL).