Phytochemical screening, anti-oxidant activity and α-amylase inhibition study using different extracts of loquat (Eriobotrya japonica) leaves

Diabetes Mellitus is an endocrine disorder which causes insulin deficiency. Medicinal plants are documented to be efficacious in the management of the disease. The current research set to determine the phytochemicals present, anti-oxidant activity and investigate the potency of Eriobotrya japonica against α-amylase inhibition. The leaves of the plant were extracted sequentially. The different extracts were evaluated for the presence of phytochemicals and their potential anti-oxidant and α-amylase inhibition activity. Methanol with the highest polarity, gave the highest yield of 20% and hexane with the lowest polarity have the lowest yield of 2.09%. This trend resembled that observed for the total flavanoid and total phenolic content analysis which gave values of 0.3822 mg QAE/mg and 3.810 mg GAE/mg respectively for methanolic and hexane extracts. The extracts of methanol recorded higher DPPH free radical scavenging activity of 87% and gave the lowest IC₅₀ of 0.5336 which was below that of ascorbic acid used as a control. Hexane extract had a higher α-amylase inhibitory activity of 24% at 1 μg/ml as compared to other extracts. Generally hexane extracts of Eriobotrya japonica exhibits mild inhibitory activity against α-amylase enzyme which is recommended than the conventional therapy which maximally inhibits the enzyme causing major side effects. The results obtained herein support the use of the plant as an anti-diabetic agent at higher concentrations.

Keywords: Diabetes; Food analysis; Food science; Hyperglycaemia; Monosaccharides; Pharmaceutical chemistry; Phytochemicals; α-amylase.