Diisoprenyl-cyclohexene/ane-Type Meroterpenoids from sp. and Their Anti-inflammatory Activities.

A secondary metabolites investigation on sp. 71-10-1-1 was carried out, which led to the obtention of nine new diisoprenyl-cyclohexene/ane-type meroterpenoids (-) and two new isoprenylbenzoic acid-type meroterpeniods (-). The structures of these isolates were established on the basis of multispectroscopic analyses, ECD, and C chemical shifts calculations, and single-crystal X-ray diffraction. Among them, biscognin A () is the first diisoprenyl-cyclohexene-type meroterpenoid with a unique 2-isopropyl-6'-methyloctahydro-1'-spiro[cyclopropane-1,2'-naphthalene] skeleton. Biscognienyne F () 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 and 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 (-) are proposed.