Antimicrobial Furancarboxylic Acids from a <i>Penicillium</i> sp.
Jinling Chang, Hongzhe Xu, Jia Zhou, Ming Zhou, Xuke Zhang, Yuanqiang Guo, Hanli Ruan
Abstract
Ten novel (1, 2, 3a, 3b, 4a, 4b, 5a, 5b, 6a, and 6b) furancarboxylic acids including four pairs of epimers (3a, 3b; 4a, 4b; 5a, 5b; 6a, 6b), together with seven known analogues (7a, 7b, 8a, 8b, 9a, 9b, and 10), were isolated from the fermentation of the soil-derived fungus Penicillium sp. sb62. Their structures were established on the basis of spectroscopic data analysis, and the absolute configurations were determined by time-dependent density functional theory electronic circular dichroism calculations, comparison of the specific optical rotation values, and modified Mosher’s method. Compounds 1–4 represent the first class of natural furancarboxylic acids featuring a thiophene moiety. Compounds 1–7 showed antimicrobial inhibitory activities against Escherichia coli, Staphylococcus aureus, and Candida albicans with MIC values ranging from 0.9 to 7.0 μg/mL, from 1.7 to 3.5 μg/mL, and from 3.3 to 7.0 μg/mL, respectively.