Pharmacological activities of a novel phthalic acid ester and iridoid glycoside isolated from the root bark of Anthocleista vogelii Planch

In this study, a novel phthalic acid ester (1) and a known iridoid glycoside (2) were isolated from the root bark of Anthocleista vogelii. The structures of the novel compound and iridoid glycoside were elucidated on the basis of their chemical and spectral data (UV, FT-IR, EI-MS, 1D and 2D NMR) and found to be phthalic acid ester, 4-ethyl-6-propyl-4,5,6,7-tetrahydro3H-2,8-benzodioxacycloundecine-1,9-dione (1) and sweroside (2). The compounds were evaluated for their in vitro inhibitory activities against pancreatic lipase, α-amylase and αglucosidase, and in vivo laxative activity in rats. The metabolite phthalic acid ester (1) exhibited moderate inhibitory activity against pancreatic lipase (IC₅₀ = 24.43 ± 0.096 µg/mL) and relatively good activity against α-glucosidase (IC₅₀ = 10.28 ± 0.015 µg/mL). Sweroside (2) displayed weak activity against α-glucosidase (IC₅₀ = 40.28 ± 0.063 µg/mL) but significantly (p<0.05) increased the feacal output of the treated animals compared to the normal and sodium picosulfate controls.