Antibacterial activity of the endophytic fungi from medicinal herb, <i>Macleaya cordata</i>

Abstract

A total of 48 endophytic fungal isolates were separated from the healthy roots of Macleaya cordata R. Br. (Papaveraceae), a traditional medicinal herb mainly distributed in China. Nine distinct isolates (Macof01 to Macof09) were selected for further taxonomical identification by morphological traits and internal transcribed spacer (ITS) rRNA gene sequence analysis. Seven genera namely Acremonium, Alternaria, Aspergillus, Bionectria, Cladosporium, Neosartorya and Penicillium were identified on the basis of their  morphological characterizations. Fungal isolates Macof02 (Bionectria ochroleuca), Macof03 (Neosartorya fischeri) and Macof05 (unidentified) have not been previously reported as the endophytic fungi according to their ITS-rDNA sequences compared with those available in the GenBank  database. Most of the fungal isolates displayed antibacterial activity. The extracts obtained from Macof02 (B. ochroleuca), Macof06 (Aspergillus sp.) and Macof08 (Acremonium sp.) exhibited strong inhibition on test bacteria. The endophytic fungi from M. macleaya could be an alternative source for producing antimicrobial agents.

Key words: Macleaya cordata, endophytic fungi, n-butanol extract,  TLC-bioautography assay, antibacterial activity.