Three New 1α-alkyldaphnane-type Diterpenoids from the Flower Buds of Wikstroemia Chamaedaphne

Three new 1α-alkyldaphnane type diterpenoids, wikstroelides R-T (1-3), together with three known analogs, genkwadane C (4), pimelea factors S6 (5) and S7 (6), two known 1α-alkyldaphnane ketal-lactone type diterpenoids, pimelotides A (7) and C (8), and a known daphnane type diterpenoid, simplexin (9), were isolated from the flower buds of Wikstroemia chamaedaphne. Their structures were elucidated by a combination of spectroscopic analyses including HRESIMS and NMR. Compounds 1-9 were evaluated for their cytotoxic activities in vitro, and most of them exhibited moderate cytotoxic activities with IC50 values ranging from 8.7-22.0 μM.