(+)-/(-)-Prunomarin A and (+)-pestalactone B, three new isocoumarin derivatives from the endophytic fungus Phomopsis prunorum

Three pairs of isocoumarin enantiomers, (+/-)-prunomarin A (1), (+/-)-pestalactone B (2), and (+/-)-3, including three new compounds, (+)-/(-)-1 and (+)-2, were isolated from the endophytic fungus Phomopsis prunorum (F4-3). These enantiomeric pairs were existed as partial racemates and were achieved by chiral-HPLC separation. Their structures were elucidated by comprehensive spectroscopic data, X-ray diffraction, and ECD analysis. Compounds (+/-)-1 represented the first examples of naturally occurring sulfoxide-containing isocoumarin derivatives. Compound 1 showed anti-inflammatory activity for NO production with an IC50 value of 84.2 mu M. Compounds (+)-/(-)-3 exhibited strong phytotoxicity against Amaranthus retroflexus. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Three pairs of isocoumarin enantiomers were isolated from the endophytic fungus Phomopsis prunorum, including three new compounds. These compounds showed anti-inflammatory activity and strong phytotoxicity against certain plants.