Two Extracts From Manihot Esculenta Leaves Efficiently Inhibit α-Glucosidase and α-Amylase: A New Approach for the Management of Diabetes

In Nigeria, the leaves of Manihot esculenta (Crantz) are eaten as vegetables. The leaves are rich in phytochemicals, valuable and natural sources of antioxidants, and are highly useful for human health and disease prevention. This study was aimed to evaluate the in vitro inhibitory effects of two extracts derived from the plant leaves on α-glucosidase and α-amylase. The total flavonoid and phenolic contents of the extracts were also assessed. 

 The leaves of M. esculenta were processed and extracted with ethanol and acetone. The extracts were evaluated for their α-glucosidase and α-amylase inhibitory activities. Also, their total flavonoid and phenolic contents were determined, using standard in vitro assays. 

The ethanol extract exhibited a higher α-glucosidase and α-amylase inhibitory activity than the acetone extract, which positively correlated with their total flavonoid and phenolic contents. In addition, the ethanol extract strongly inhibited the α-glucosidase activity (IC50: 0.77±0.03 mg/mL) than Acarbose (IC50: 1.52±0.14 mg/mL). However, both extracts of ethanol (IC50: 1.29±0.02 mg/mL) and acetone (IC50 1.66±0.05 mg/mL) were less effective in inhibiting  α-amylase compared with that of Acarbose (IC50 0.99±0.02 mg/mL). Comparatively, the percent inhibition of the extracts and Acarbose were in this order: ethanol extract > Acarbose > acetone extract.

The results suggest that the extract of M. esculenta leaves have anti-hyperglycemic effects. They are potential alternative antioxidants that could be used to reduce oxidative stress in the body and in the management of diabetes.