Phytochemical Screening and Hypoglycemic Property of Globimetula braunii (Loranthaceae) Leaf Extracts

Aims: To carry out phytochemical screening, acute toxicity test and to investigate the hypoglycemic potential of the ethanol extract and fractions of Globimetula braunii leaves.

Place and Duration of Study: Department of Pharmacognosy and Drug Development and Animal House, Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Ahmadu Bello University, Zaria, Nigeria. August 2016 to April 2017.

Methodology: The leaf powder (2.1 kg) was extracted with 7.0 L of ethanol using the infusion method. The extract obtained was further fractionated each with 2.7 L petroleum ether 60/80, ethyl acetate and n-butanol to obtain PEF, EAF and NBF fractions respectively. Phytochemical screening of the ethanol extract and TLC profiling of the different fractions were carried out. Acute toxicity testing via the oral route of administration was conducted on Laboratory mice. The hypoglycemic property of the extract and fractions on Alloxan induced hyperglycemic adult Wistar rats was investigated.

Results: The percentage yield of the ethanol extract was 10.22 % w/w. The PEF, EAF, NBF and AQF fractions yielded 3.8%, 6.59%, 14.21% and 48.36% w/w respectively. The phytochemical screening of the ethanol extract showed the presence of alkaloids, anthraquinones, flavonoids, saponins, steroids, phenols/tannins and triterpenoids. These were redistributed among the fractions of the extract. The extract was practically non-toxic when administered orally (LD50>5000). Treatment with 250 and 500 mg/kg of ethanol extract produced a significant effect (P<.001) at 1 h, 2 h and 4 h post administration via oral route when compared with 500 mg/kg metformin. The ethanol extract, petroleum ether and n-butanol fractions (500 mg/kg) showed significant blood glucose reduction effect (P<.001) after 1 h, 2 h and 4 h treatment.

Conclusion: A Pharmacological study of the extract and fractions of G. braunii leaves have significantly proven the safety and significant blood glucose reduction effect. The hypoglycemic property may be linked to their phytoconstituents especially the flavonoids, phenols and triterpenoids.