Citriquinolinones A and B: Rare Isoquinolinone-Embedded Citrinin Analogues and Related Metabolites from the Deep-Sea-Derived Aspergillus versicolor 170217

• Published in: Marine drugs 2023-09, Vol.21 (10), p.504
• Main Authors: Lin, Shui-Hua, Yan, Qing-Xiang, Zhang, Yong, Wu, Tai-Zong, Zou, Zheng-Biao, Liu, Qing-Mei, Jiang, Jia-Yang, Xie, Ming-Min, Xu, Lin, Hao, You-Jia, Liu, Zhu, Liu, Guang-Ming, Yang, Xian-Wen
• Format: Article
• Language: English
• Subjects: anti-food allergic activity; Aspergillus versicolor; Bridges; Citrinin; citrinin–isoquinolinone hybrid; Deep sea; Deep sea environments; Deep water; deep-sea-derived fungus; Emodin; Food allergies; Fungi; Metabolites; NMR; Nuclear magnetic resonance; Phenols; Probability theory; Statistical analysis; theoretical–statistical approaches
• ISSN: 1660-3397; 1660-3397
• DOI: 10.3390/md21100504

A systematic chemical investigation of the deep-sea-derived fungus Aspergillus versicolor 170217 resulted in the isolation of six new (1–6) and 45 known (7–51) compounds. The structures of the new compounds were established on the basis of exhaustive analysis of their spectroscopic data and theoretical–statistical approaches including GIAO-NMR, TDDFT-ECD/ORD calculations, DP4+ probability analysis, and biogenetic consideration. Citriquinolinones A (1) and B (2) feature a unique isoquinolinone-embedded citrinin scaffold, representing the first exemplars of a citrinin–isoquinolinone hybrid. Dicitrinones K–L (3–4) are two new dimeric citrinin analogues with a rare CH-CH3 bridge. Biologically, frangula-emodin (32) and diorcinol (17) displayed remarkable anti-food allergic activity with IC50 values of 7.9 ± 3.0 μM and 13.4 ± 1.2 μM, respectively, while diorcinol (17) and penicitrinol A (20) exhibited weak inhibitory activity against Vibrio parahemolyticus, with MIC values ranging from 128 to 256 μM.