Isolation and Quantification of Alternariols from Endophytic Fungus, Alternaria alternata: LC-ESI-MS/MS Analysis

摘要

An endophytic fungus, Alternaria alternata was isolated from Grewia asiatica. Upscaling of the fermentation broth led to the isolation of a new structural isomer of alternariol (3), along with alternariol (1) and alternariol 9-methyl ether (2). Additionally, an LC-ESI-MS/MS method was developed for the simultaneous detection and quantification of 1-3 through multiple reaction monitoring (MRM). The limit of quantification (LOQ) and detection (LOD) were fewer than 5.0, 2.0, 0.3 and 1.5, 0.7, 0.1 mg/ml, respectively for 1-3. Furthermore, 1 and 3 showed significant activity against gram-positive bacteria, Staphylococcus aureus and 1 displayed MIC comparable to that of ciprofloxacin against VRE and MRSA.