Anti-inflammatory terpenylated coumarins from the leaves of Zanthoxylum schinifolium with α-glucosidase inhibitory activity

Nine terpenylated coumarins, namely 7-[(E)-3′,7′-dimethyl-6′-oxo-2′,7′-octadienyl]oxy-coumarin (1), schinilenol (2), schinindiol (3), collinin (4), 7-[(E)-7′-hydroxy-3′,7′-dimethy-locta-2′,5′-dienyloxy]-coumarin (5), 8-methoxyanisocoumarin (6), 7-(6′R-hydroxy-3′,7′-dimethyl-2′E,7′-octadienyloxy)coumarin (7), (E)-4-methyl-6-(coumarin-7′-yloxy)hex-4-enal (8), and aurapten (9), along with a 4-quinolone alkaloid (10) and integrifoliodiol (11), were isolated from the leaves of Zanthoxylum schinifolium. Of the isolates, compounds 4 and 7 potentially inhibited NO production in lipopolysaccharide (LPS)-stimulated macrophage RAW264.7 cells, with IC₅₀ values of 5.9 ± 0.8 and 18.2 ± 1.8 μM, respectively. Furthermore, compounds 4 and 7 dose-dependently reduced the LPS-induced iNOS expression. Moreover, pre-incubation of cells with 4 and 7 significantly suppressed LPS-induced COX-2 protein expression. In addition, compounds 4, 7, 8, and 10 showed strong α-glucosidase inhibitory effects, with IC₅₀ values of 92.1 ± 0.7, 90.6 ± 0.9, 78.2 ± 0.2, and 82.4 ± 0.8 μM, respectively. Compounds 1, 5, and 11 displayed moderate effects with IC₅₀ values of 161.6 ± 0.3, 164.4 ± 1.1, and 155.4 ± 0.9 μM, while acarbose, a positive control, possessed an IC₅₀ value of 121.5 ± 1.0 μM. This is the first investigation on the α-glucosidase inhibitory effect of components from Zanthoxylum schinifolium. Further studies should be made on active compounds.