Antidiabetic Potential of The Leaf Extracts of Phragmanthera incana (Schum.) Balle Harvested on Albizia lebbeck
Author(s): Elizabeth Oluwakemi BAMGBADE, Samson Oluwaseyi FAMUYIWA, Kolade Olatubosun FALOYE, Marcus Durojaye AYOOLA, Charlotte Mungho TATA, Marthe Carine Djuidje FOTSING and Derek Tantoh NDINTEH
Introduction: This comparative study investigated the antidiabetic potentials of the various organic solvents of the leaf extracts of Phragmanthera incana with the aim of determining the best organic solvent for its antidiabetic activity.
Methodology: The pulverized leaves of the plant were subjected to successive extraction using different organic solvents to obtain its n-hexane (HPI), chloroform (CPI), ethyl acetate (EPI), methanol (MPI) and aqueous butanol (BPI) extracts. The hypoglycaemic and antihyperglycaemic effects of the extracts were carried out on normoglycaemic and glucose-induced hyperglycaemic rats, respectively at 100, 200 and 400 mg/kg using glibenclamide (5 mg/kg) as positive control. The most effective antihyperglycaemic doses of the extracts were used to determine its anti-diabetic activity on streptozotocin-induced diabetic rats. The results obtained from the study were subjected to analysis of variance (ANOVA), followed by Student–Newman-Keuls post hoc tests and p< 0.05 was considered significant.
Results: CPI and BPI extracts lacked hypoglycaemic effect on normal rats while HPI, EPI and MPI extracts gave significantly (p< 0.05) lower hypoglycaemic effect than glibenclamide. HPI (400 mg/kg) with 54 % blood glucose level reduction at 4 h was the most active antihyperglycaemic extract, followed by EPI (400 mg/kg) with 48 % activity while BPI (200 mg/kg), MPI (200 mg/kg) and CPI 400 (mg/kg), were comparable in activity with 34, 34 and 38 % blood glucose level reduction, respectively at 4 h. In the streptozotocin- induced diabetic rats, HPI gave a significantly (p<0.05) better hyperglycaemia lowering effect than glibenclamide (5 mg/kg) on days 4 and 7 and comparable (p>0.05) effect on days 10, 14 and 21. The 57 and 70 % antidiabetic effect of CPI given on days 14 and 21 were comparable to 62 and 75 % of activity elicited on the same days. MPI and BPI with comparable 63 and 66 % effect, respectively on day 21 that were significantly less active than glibenclamide were the least active extracts.
Conclusion: The study concluded that all the leaf extracts of Phragmanthera incana from the different organic solvents possessed antidiabetic activity to various degrees in both glucose and streptozotocin-induced hyperglycaemic rats. The n-hexane extract (HPI), with the highest antihyperglycaemic effect in the two models used in the study confirmed that the extract contained the highest concentration of the active constituents and hence, n-hexane was the best solvent for extraction.