Assessment of phytoconstituents and antidiabetic activity of the crude extract and partitioned fractions of Maytenus senegalensis (Lam.) Exell (Celastraceae) root bark

Abstract

Aims:To investigate the antidiabetic activity of the root bark ofMaytenus senegalensisethnomedically used in Nupeland for the management of diabetesandisolatephytoconstiteunts responsible for the pharmacological activities.Study Design:Air-dried root barkMaytenussenegalensisground into a fine powder. Thepulverized material was macerated in 70% methanol at room temperature for 72h. Theextracts were concentratedin vacuousing rotary evaporator at 35ºC. Antidiabetic activitywas determined on the crude methanolic extract and partitionedfractionsPlace and Duration of Study:Department of Chemistry and Department of Biochemistry, School of Natural and Applied Sciences, Federal University of Technology,Minna, Nigeria between January, 2012 and July, 2013.Methodology:The present study reports the phytoconstituents evaluation as well asantidiabetic activity determination of the root bark extract ofM. senegalensison alloxan-induced diabetic rats. Phytoconstituents analysis and characterization of the root barkextract ofM. senegalensiswere determined using standard phytochemical methods andGC-MS analysis respectively. The crude extract was partitioned using different solvents ofvarying polarities and the fractions obtained were tested for their phytoconstituents.Results:The preliminary phytochemicalanalysisofM. senegalensisroot barkindicatesthe presence ofalkaloids,flavonoids, saponins,tanninsand steroidal compounds.Anthraquinones was completely absent. The root bark ofMaytenussenegalensiswasextracted by 70% methanol which was then partitioned using four solvents of differentpolarities.The crude extract and solvent soluble fractions were used todeterminetheantidiabetic activity against alloxan induced (150mg/kg body weight) diabetic rats, afteroraladministration at a dose of 200mg/kg body weight for two weeks. The result revealedreduction in the elevated blood glucose level by 29.75%. Treatment with the knownantidiabetic drug, glibenclamide (5mg/kg body weight) lowered blood glucose level by27.03% indicating significant improvement in activity.Results obtained indicate that 70%methanolic fraction (aqueous methanol soluble fraction) has highest and most effectiveactivity. This aqueous methanol fraction was then subjected to column and thin layerchromatography as well as GC-MS analysis. The GC-MS spectrum reveals the presenceof seven different compounds whichmay havecontributed to the ethnomedicinalproperties of this plant.Conclusion:Scientific research has supported the ethnomedicinal claims thatM.senegalensisis useful in diabetes management. However, the isolation, purification andcharacterization as well asmechanism of action of bioactive constituents underlying itscurative properties are suggested