Pestalotiopisorin B, a new isocoumarin derivative from the mangrove endophytic fungus Pestalotiopsis sp. HHL101

Abstract

A new isocoumarin derivative pestalotiopisorin B (1), along with six known compounds, (R)-(-)- mellein methyl ether (2), pestalotiopyrone G (3), (R)-mevalonolactone (4), pestalotiollides A–B (5–6) and pestalotiopsol A(7) were isolated from Pestalotiopsis sp., an endophytic fungus obtained from Chinese mangrove plant Rhizophora stylosa. Their structures were elucidated unambiguously by the comprehensive analysis of extensive spectroscopic data. Compound 1 exhibited modest antibacterial activity against Escherichia coli and Pseudomonas aeruginosa with 12.5 μg/ml, 50 μg/ml, respectively. Compound 4 showed moderate calcineurin inhibitory activity towards p-nitrophenyl phosphate (IC₅₀ =134.29 ± 5.377 μM).

Graphical Abstract

Keywords:

• Rhizophora stylosa
• endophytic fungi
• Pestalotiopsis sp.
• antibacterial activity
• calcineurin inhibitory activity

Additional information

Funding

This study was funded by grants from the National Natural Science Foundation of China (No. 81660584), Key Research Program of Hainan Province (ZDYF2017099) and the Innovative Research Team Grant of the Natural Science Foundation of Hainan University (hdkytg201705) are gratefully acknowledged.