Three new compounds, 3,7-dimethy-7-methoxy-3-octene-5-one-1-O-β-d-glucopyranoside (1), 3,7-dimethy-7-methoxy-3(Z)-octene-5-one-1-O-β-d-glucopyranoside (2) and 3,7-dimethy-3-hydroxy-6-octene-5-one-1-O-β-d-glucopyranoside (3), together with fourteen known compounds (4–17) were isolated from the leaves and shoots of S. laevigata. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis, including one- and two-dimensional NMR, as well as mass spectral data. All isolates were evaluated for their α-glucosidase inhibitory and antioxidant activities. The results demonstrated that 3,7-dimethyl-3(Z),6-ocatdien-5-one-1-O-β-d-glucoside (7) and sitosteryl β-d-glucoside (17) exhibited α-glucosidase inhibitory effects with IC₅₀ values of 220.0 and 113.0 μM, respectively.