New tricyclic prezizaane sesquiterpenoids from agarwood

Ten new tricyclic prezizaane types sesquiterpenoids (1-10) were isolated from ethyl ether extract of agarwood originated from Aquilaria sp. Their structures were unambiguously elucidated on the basis of 1D and 2D NMR spectra as well as by HRESIMS data. The absolute configuration of the new prezizaenes 1, 2 and 4 was determined by single-crystal X-ray diffraction, while TDDFT-ECD method was applied for 6. Compounds 4 and 5 displayed significant inhibitory activities toward α-glucosidase with IC₅₀ values of 0.22 and 1.99 mM, respectively.