Exploring the anti-diabetic potential of banana peel extracts: Impact of maceration and ultrasonication on bioactive compounds and glycemic control in diabetic rabbits

Banana peel is an excellent source of fibre and antioxidants. In the current study, extraction parameters for banana peels were optimized using various extraction methods (sonication and maceration), solvents (acetone, ethanol, and methanol) and solvent concentrations (25, 50, 75, 100 %). Furthermore, the antioxidant, antimicrobial and in-vivo diabetic potential of banana peel extracts (BPE) was investigated. Based on optimization results, the highest TPC (31.45 mg GAE/g), TFC (22.15 mg QE/g), DPPH (82.52 %), and FRAP (29.51 %) activity was shown by 50 % sonicated ethanolic banana peel extracts (SEBPE). Similarly, 50 % SEBPE showed the highest microbial inhibition zone. However, it was in a dose-dependent manner. The optimum dose was 750 µl/ml for bacterial strains and 500 µl/ml for S. cerevisiae. Furthermore, the administration of SEBPE significantly (p < 0.05) improved the glycemic indicators in diabetic rabbits compared to control subjects. The highest efficacy was seen in the G5 group, receiving (750 ml of SEBPE/kg body weight) with 205-109 mg/dL and 6.85-4.51 % serum glucose and HbA1c%, respectively, for 30 days. Biochemical markers such as serum protein, albumin, creatinine and lipid profile showed non-significant (p > 0.05) variations. However, a significant reduction in total cholesterol (159-90 mg/dL) was attributed to higher fibre. Hence, it can be concluded that sonication improves the antioxidant potential of SEBPE due to the increased release of polyphenols, which are responsible for their enhanced antimicrobial and anti-diabetic properties. However, further investigations are required to explore the effectiveness of SEBPE against diabetes co-morbidities such as renal dysfunction.