Four New Highly Oxygenated Eremophilane Sesquiterpenes from an Endophytic Fungus Boeremia exigua Isolated from Fritillaria hupehensis

Abstract

Four new eremophilane-type sesquiterpenes, boeremialanes A–D (1–4) were obtained from solid substrate cultures of Boeremia exigua (Didymellaceae), an endophytic fungus isolated from Fritillaria hupehensis (Liliaceae). Boeremialanes A–C (1–3) are highly oxygenated eremophilanes with a benzoate unit attached at the C-13 position and are rarely found in nature. Their structures and absolute configurations were determined by extensive spectroscopic methods, electronic circular dichroism (ECD), and nuclear magnetic resonance (NMR) calculations with DP4+ analysis. Boeremialane D (4) potently inhibited nitric oxide production in lipopolysaccharide-treated RAW264.7 macrophages with an IC50 of 8.62 μM and was more potent than the positive control, pyrrolidinedithiocarbamate (IC50 = 23.1 μM).

Research Progress on Sesquiterpene Compounds from Artabotrys Plants of Annonaceae

“…Eremophilane-type sesquiterpenes, derived from the biosynthetic precursor farnesy diphosphate (FPP), represent a distinct group within the bicyclic sesquiterpene com pound family. These compounds are characterized by their unique irregular bicycli structures, with structural variations primarily arising from various oxidations on the bi cyclic skeleton and the isopropyl side chain [93]. Related studies have shown that thes compounds displayed anti-inflammatory effects and can inhibit the NO produced by lip opolysaccharide (LPS)-induced RAW 264.7 macrophages [94].…”

Secondary Metabolites from Fungi—In Honor of Prof. Dr. Ji-Kai Liu’s 60th Birthday

“…Further studies on endophytic fungi by Ai et al and Yu et al report new eremophilane sesquiterpenoids and new sativene, as well as longifolene sesquiterpenoids plus two new xanthones from Boeremia exigua isolated from Fritillaria hupehensis and the Kiwifruitassociated fungus Bipolaris sp., highlighting the vast chemical diversity to be explored by these plant-associated fungi [51,52].…”