Nitrogenous Sesquiterpenoids from the South China Sea Nudibranch Hexabranchus sanguineus and Its Possible Sponge‐Prey Acanthella cavernosa: Chiral Separation, Stereochemistry and Chemical Ecology

• Published in: Chinese journal of chemistry Vol. 40; no. 2; pp. 235 - 246
• Main Authors: Shen, Shou‐Mao, Zhang, Zai‐Yong, Yao, Li‐Gong, Wang, Jian‐Rong, Guo, Yue‐Wei, Li, Xu‐Wen
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag GmbH & Co. KGaA 15.01.2022; Wiley; Wiley Subscription Services, Inc
• Subjects: Acanthella cavernosa; Chemical ecology; Chemistry; Chemistry, Multidisciplinary; Chiral separation; Circular dichroism; Data analysis; Density functional theory; Dichroism; Enantiomers; Hexabranchus; Hexabranchus sanguineus; High-performance liquid chromatography; Liquid chromatography; NMR; Nuclear magnetic resonance; Physical Sciences; Prey; Quantum mechanics; Science & Technology; Sesquiterpenoids; Stereochemistry; South China Sea; METABOLITES; DITERPENOIDS; Acanthella cavernosa; Chiral separation; ISOTHIOCYANATE; Hexabranchus sanguineus; KALIHINOL; Stereochemistry; Chemical ecology; MACROLIDES; TERPENOIDS
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.202100676

Comprehensive Summary A detailed chemical investigation of the South China Sea nudibranch Hexabranchus sanguineus, as well as its possible sponge‐prey Acanthella cavernosa, led to the isolation of fifteen new nitrogenous sesquiterpenoids, namely ximaocavernosins A−O, including seven cadinanes (1—7), seven spiroaxanes (12—18) and one aromadendrane (19), together with thirteen known related compounds (8—11 and 20—28). Compounds (±)‐1—9 (except for 4 and 6) were further separated by chiral‐phase HPLC to their corresponding unequal enantiomers, respectively. Their structures and absolute configurations were determined by a combination of extensive spectroscopic data analysis, quantum mechanical nuclear magnetic resonance (QM‐NMR) methods, Mosher's method, X‐ray diffraction analysis and/or time‐dependent density functional theory/electronic circular dichroism (TDDFT‐ECD) calculation. The commonly existed nitrogenous sesquiterpenoids in these two animals are suggested to be chemical markers for their prey‐predator relationship. Fifteen new nitrogenous sesquiterpenoids were isolated from the South China Sea nudibranch Hexabranchus sanguineus and its possible sponge‐prey Acanthella cavernosa. Seven compounds were further separated by chiral‐phase HPLC to their corresponding unequal enantiomers, respectively. Four commonly existed nitrogenous sesquiterpenoids in these two animals are suggested to be chemical markers for their prey‐predator relationship.