LC-MS-based metabolite profiling of aqueous extract of Pergularia tomentosa L. and its anti-hyperglycemic effect

Objective(s): In this study, to find scientific evidence for the traditional use of Pergularia tomentosa as an anti-diabetic remedy, the effects of its aqueous extract on streptozotocin-induced diabetes mellitus in rats were evaluated. Materials and Methods: Wistar rats were fasted overnight and diabetes mellitus was induced using streptozotocin (50 mg/kg body weight). The rats were randomly and equally divided into four groups (n=5): group I (normoglycaemic control), group II (diabetic rats), group III (diabetic rats treated with 200 mg/kg BW of an aqueous extract of P. tomentosa), group IV (normoglycemic rats treated with 200 mg/kg BW of an aqueous extract of P. tomentosa). Chemical profiling of the aqueous extract was carried out using liquid chromatography coupled with electrospray ionization and multiple-stage linear ion-trap and orbitrap highresolution mass spectrometry (LC-ESI/LTQOrbitrap/MS/MS). In addition, the quantitative determination of the main cardenolides in the extract was carried out by an analytical approach based on LC coupled to tandem mass spectrometry with ESI source and hybrid triple quadrupole-linear ion trap mass analyzer (LCESI/QTrap/MS/MS). Results: Aqueous extract of P. tomentosa showed a reasonable reduction in blood glucose level. Probably, the P. tomentosa effect on hyperglycemic and hyperlipidemic diabetic animals was associated with antioxidant properties, triglyceride levels, as well as liver enzymes. Meanwhile, LC-ESI/LTQOrbitrap/MS/MS analysis led to identification of double-linked cardenolides along with cardenolides and flavone glycosides as the main bioactive compounds. Conclusion: The extract decreased the glucose level and induced a beneficial effect on the lipid profile, probably due to the presence of cardenolide glycosides.