Cytotoxic benzopyranone and xanthone derivatives from a coral symbiotic fungus Cladosporium halotolerans GXIMD 02502

Abstract

Coral-derived microorganisms have been historically proven to be prolific sources of bioactive secondary metabolites. Twelve benzopyranone and/or xanthone derivatives, including a new benzopyranone with an uncommon carboxyl group at C-8, coniochaetone K (1), were obtained from the Beibu Gulf-derived coral symbiotic fungus Cladosporium halotolerans GXIMD 02502. Their structures were determined by extensive spectroscopic data interpretation and comparison with literature values. The absolute configuration of 1 was accomplished by comparison of specific optical rotation as well as quantum chemical ECD calculations. The in vitro cytotoxicity of compounds 1–12 against two human prostatic cancer cell lines, C4-2B and 22RV1, were evaluated. And compounds 1, 3, 6–8, and 10–11 demonstrated significant cytotoxicity with inhibitions ranging from 55.8% to 82.1% at the concentration of 10 μM.

Graphical Abstract

Keywords:

• Benzopyranones
• xanthones
• cytotoxicity
• coral-derived fungi
• Cladosporium halotolerans

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project was supported by the Special Fund for Bagui Scholars of Guangxi (05019055), the Natural Science Foundation of Guangxi (2020GXNSFBA159001),Guangxi Young and Middle-aged University Teachers’ Scientific Research Ability Enhancement Project (2020KY07032), Development Program of High-level Talent Team under Qihuang Project of Guangxi University of Chinese Medicine (GXUCM) (2018006), the Scientific Research Foundation of GXUCM (2019BS021, 2018ZD005), the Science and Technology Planning Project of Guangdong Province (2017A050506042), College students’ innovation and entrepreneurship training programs of Guangxi (202010600093).