Protolichesterinic Acid: A Prominent Broad Spectrum Antimicrobial Compound from the LichenUsnea albopunctata

[摘要] The aim of this study is to investigate the antimicrobial compounds present in the lichenUsnea albopunctata. Ethyl acetate extract was purified by silica gel column chromatography to obtain a major compound and the chemical structure was characterized by1H-NMR,13C-NMR, DEPT,1H-1H COSY, HMQC, HMBC, UV, and HR-MS spectroscopic methods as protolichesterinic acid. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method and agar disc diffusion method against thirteen human pathogenic bacterial and four fungal strains. Protolichesterinic acid recorded significant broad spectrum antimicrobial property. The best antibacterial activity was recorded againstK. pneumonia(0.25 μg/mL) andV. cholerae(0.5 μg/mL). Significant antifungal activity was recorded againstT. rubrum(0.12 μg/mL), which is significantly better than the standard antifungal agent. Protolichesterinic acid is reported for the first time fromUsnea albopunctata. Antifungal activity of protolichesterinic acid against medically important fungi is also reported for the first time. Thus the results of the present study suggest that protolichesterinic acid has significant antimicrobial activities and has the strong potential to be developed as an antimicrobial drug after further clinical evaluation.

[学科分类] 药学