Orsellinic acid derivatives with antibacterial activity from Alternaria sp. TY22 associated with Typha orientalis

Abstract

Filamentous fungi are renowned for producing structurally diverse secondary metabolites with significant biological activities. In the present study, seven compounds, including a pair of new isomeric 2,3-butylene orsellinate derivatives (1a/1b) and five known compounds (2–6), were isolated from the endophytic fungus Alternaria sp. TY22 derived from Typha orientalis. Their structures were elucidated by comprehensive spectroscopic analysis. Antibacterial evaluation revealed that 2 and 3 showed strong antibacterial activity against Staphylococcus aureus and Bacillus subtilis with MIC values ranging from 4 to 16 μg/mL, and the new isomers 1a/1b displayed moderate antibacterial activity with MIC values of 64 and 32 μg/mL against S. aureus and B. subtilis, respectively.