Heptelidic acid oligomers from the fungal strain MSX83315

Fungal-derived sesquiterpenes represent a unique category of secondary metabolites that distinguishes them from other natural sources. Sesquiterpenoid oligomers are a special type of natural product that consists of at least two linked sesquiterpenoid units. Numerous biosynthetic reactions occur throughout the oligomerization process, including oxidation, chlorination, hydrolysis, and etc. Theoretically, the large number of permutations on the building blocks makes this class worthy of further exploration. Due to our interest in the chemical diversity of fungi, four previously undescribed heptelidic acid derived oligomeric sesquiterpenes, including two trimeric and two tetrameric sesquiterpenes, along with 13 known monomeric, dimeric, and trimeric sesquiterpenes, were isolated from fungal strain MSX83315. Structures, inclusive of absolute configurations, were assigned by detailed spectroscopic analysis, ECD calculations, and biosynthetic considerations. The structural diversity generated by this fungal strain was interesting, as few trimeric and tetrameric sesquiterpenes have been reported from Nature. Acknowledgements: This research was supported in part via the National Institutes of Health/National Cancer Institute via P01 CA125066. Perihan Gürbüz appreciates the Scientific and Technological Research Council of Turkey (2219-International Postdoctoral Research Fellowship Program; Grant No: 1059B192200255) for its financial support. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany