Caryophyllene sesquiterpenoids with various ring systems from the fungus Pestalotiopsis chamaeropis

Six undescribed caryophyllene sesquiterpenoids named pestalotiopsins O–T, along with eight known analogues, were obtained from the fungus Pestalotiopsis chamaeropis. Their structures and absolute configurations were assigned by NMR spectroscopic analyses, HRESIMS, single-crystal X-ray diffraction, electronic circular dichroism (ECD) calculations, Mo2(OAc)4-induced ECD, and chemical derivatization. Pestalotiopsin P represents the first example of a caryophyllene sesquiterpenoid possessing an oxatricyclo [7.2.2.03.6]tridecane decorated with a rare bridgehead double bond, while pestalotiopsin Q has an oxatricyclic [6.3.1.01,4]dodecane skeleton with an unusual ether bridge between C-1 and C-5. These undescribed caryophyllene sesquiterpenoids were screened for their cytotoxic and anti-inflammatory activities. Six undescribed caryophyllene sesquiterpenoids and eight known analogues were obtained from the fungus Pestalotiopsis chamaeropis. Pestalotiopsin P represents the first example of caryophyllene sesquiterpenoid possessing an oxatricyclo [7.2.2.03.6]tridecane decorated with a rare bridgehead double bond, while pestalotiopsin Q has an oxatricyclic [6.3.1.01,4]dodecane skeleton with an unusual ether bridge. [Display omitted] •Six undescribed caryophyllene sesquiterpenoids were isolated from P. chamaeropis.•Their configurations were elucidated by X-ray diffraction analyses and ECD.•Pestalotiopsin P possessed an oxatricyclo [7.2.2.03.6]tridecane decorated a bridgehead double bond.•Pestalotiopsin Q has an oxatricyclic [6.3.1.01,4]dodecane skeleton with an unusual ether bridge.