Comparative Study on the Phytochemical Compositions and Antihyperglycemic Potentials of the Leaves Extracts of Combretum paniculatum and Morinda morindoides

Abstract

The phytocheimcal components and antihyperglycemic potential of methanol and ethanol leaves extracts of Combretum paniculatum Vent (Combretaceae) and Morinda morindoides (Baker) Milne-Redh (Rubiaceae) grown in Nigeria have been studied. The phytochemical composition was determined by established methods while the in vitro hypoglycemic effect was performed by determining the inhibitory potentials of the extracts on α-amylase and α-glucosidase. Results showed that the ethanol extract of C. paniculatum displayed the most potent inhibition of both α-amylase (IC50: 5.06 mg/mL) and α-glucosidase (IC50: 1.96 mg/mL). The ethanol extract of C. paniculatum inhibited α-amylase and α-glucosidase in a non-competitive and mixed non-competitive manner. The presence of phytochemicals such as phenols, steroids, flavonoids and athraquinones were confirmed in the extracts. Aims: To determine the phytochemical compositions and hypoglycemic potentials of the methanol and ethanol leaves extracts of Combretum paniculatum and Morinda morindoides. Study Design: Extraction of the air-dried and pulverized leaves of C. paniculatum and M. morindoides with both methanol and ethanol, and testing the various extracts for the phytochemical composition and hypoglycemic potentials. Place and Duration of Study: The leaves of C. paniculatum were collected from Ibefun, Oyo State, in May 2013 while those of M. morindoides were collected from Etegbin Area, Shibiri, Lagos, State, Nigeria, in June 2013. Methodology: The pulverized leaves were extracted separately with ethanol and methanol for 24 h. The resulting infusions were decanted, filtered and evaporated in a rotary evaporator.  The dried extracts were weighed and dissolved in dimethylsulphoxide (DMSO) to yield a stock solution from which lower concentrations were prepared. Phytochemical compositions of the extracts were determined using the methods described previously. Moreover, the hypoglycemic potentials were evaluated as described previously. Results: The ethanol extract of C. paniculatum possessed mild inhibition of α-amylase and strong inhibition of α-glucosidase compared to other extracts. Conclusion: The present results justify the use of C. paniculatum in the treatment of sugar related disorders in Nigeria.