α-Glucosidase Inhibitory and Antioxidant Acridone Alkaloids from the Stem Bark of Oriciopsis glaberrima ENGL. (Rutaceae)

The CH2Cl2/MeOH extract of the stem bark of Oriciopsis glaberrima ENGL. afforded four new acridone alkaloids namely oriciacridone C,D,E and F along with six known compounds: atalaphyllidine, oleanolic acid, butulinic acid, β-sitosterol, stigmasterol, glucoside of stigmasterol and one synthetically known acridone: 1,3,5-trihydroxy-4-prenylacridone. The structures were established on the basis of MS, 1D and 2D NMR experiments. The acridones 1,4 and 5 showed potent activity against α-glucosidase, while the acridones 1-5 showed moderate free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH).