Diisoprenyl-cyclohexene/ane-Type Meroterpenoids from <i>Biscogniauxia</i> sp. and Their Anti-inflammatory Activities
Huan Zhao, Jian Zou, Wei Xü, Dan Hu, Liang‐Dong Guo, Jiaxu Chen, Guo‐Dong Chen, Kwok‐Fai So, Xin‐Sheng Yao, Hao Gao
Abstract
A secondary metabolites investigation on Biscogniauxia sp. 71-10-1-1 was carried out, which led to the obtention of nine new diisoprenyl-cyclohexene/ane-type meroterpenoids (1–9) and two new isoprenylbenzoic acid-type meroterpeniods (10–11). The structures of these isolates were established on the basis of multispectroscopic analyses, ECD, and 13C chemical shifts calculations, and single-crystal X-ray diffraction. Among them, biscognin A (1) is the first diisoprenyl-cyclohexene-type meroterpenoid with a unique 2-isopropyl-6′-methyloctahydro-1′H-spiro[cyclopropane-1,2′-naphthalene] skeleton. Biscognienyne F (5) is the first diisoprenyl-cyclohexene-type meroterpenoid with a cyclic carbonate. The anti-inflammatory assays of the majority of compounds were evaluated, which exhibited that compounds 3 and 5 can obviously inhibit pro-inflammatory cytokines TNF-α and IL-6 productions. This is the first report for diisoprenyl-cyclohexene-type meroterpenoids with anti-inflammatory activity. Moreover, the possible biogenetic pathways of the majority of compounds (1–5) are proposed.