Calkbisabenacid, A New Bisabolane Sesquiterpenoid from the Leaves of Callicarpa kwangtungensis.

A new bisabolane sesquiterpenoid, named calkbisabenacid (1), was isolated from the leaves of Callicarpa kwangtungensis, along with four known compounds: 5-O-coumaroylquinic acid (2), kaempferol (3), and soyasapogenol B (4). The structure of compound 1 was determined by ¹H NMR, 13C NMR, COSY, HSQC, and HMBC spectra, in combination with the HRESIMS data. The absolute configuration of C-1 in compound 1 was determined by comparing the experimental ECD spectrum with the calculated ECD spectra of the two possible stereoisomers. The known compounds were identified by comparing their NMR data with those reported in the literature. Compound 4 was isolated from this species for the first time. None of these compounds demonstrated any inhibitory effects against Staphylococcus aureus ATCC 25923. [ABSTRACT FROM AUTHOR]