In vitro Inhibitory Effects of Protein Isolates from Unripe Plantain (Musa paradisiaca) on Key Enzymes Linked to Type-2 Diabetes and Obesity

Abstract

Aims: This study was carried out to examine and characterize the effects of protein isolates from unripe plantain on enzymes linked with type-2 diabetes(α-amylase) and obesity (Pancreatic Lipase) using an in vitro model. Place and Duration of Study: Department of Biochemistry, Lagos State University, Ojo, Lagos, Nigeria between July 2019 and January 2020. Methodology: Proteins were isolated from dried raw flour of unripe plantain, and enzyme inhibition assays were conducted in the presence of protein isolates using α-amylase from Saccharomyces cerevisiae and porcine pancreatic lipase. Acarbose and Orlistat were used as the standard inhibitors respectively. Percentage inhibition of the two enzymes and the IC50 values were determined. The effects of pH, temperature and salts on the inhibitory activity of the protein isolates were also determined.  Results: The protein isolates showed maximum percentage inhibition on α-amylase activity at 87% (IC50 value 0.46±1.9 mg/mL) compared with acarbose with a maximum inhibitory potential of 86% (IC50 value 0.51±3.6 mg/mL) and maximum percentage inhibition on pancreatic Lipase at 91% (IC50 value 0.73±3.2 mg/mL) compared with Orlistat with a maximum inhibitory potential of 97% (IC50 value 0.61±9.4 mg/mL). The optimum pH for both α-amylase and pancreatic lipase inhibitory activity was observed to be pH 9.0 and, the optimum temperature for α-amylase and pancreatic lipase inhibitory activity was observed to be at 40oC. At certain concentrations the inhibitory activities of the unripe plantain protein isolates were affected by the salts. Conclusion: These results showed the presence of α-amylase and pancreatic lipase inhibitors in unripe plantain which indicates that this plant can be beneficial in the construction of anti-diabetes and anti-obesity medications.