Abstract

The dried plantain pulps were crushed and milled into flour (Raw flour), while a portion of its flour was reconstituted in boiling water to form a thick paste known locally in Western Nigeria as ‘amala’. This was dried and milled into ‘Amala’ flour. The aqueous extracts of raw and ‘amala’ flour were prepared (1 g/20 mL). The phenolic contents, vitamin C and antioxidant properties (DPPH and OH radical scavenging ability, reducing power and iron-chelating ability) were analyzed. The α-amylase, α-glucosidase, angiotensin-1-converting enzyme (ACE) inhibitory activities and EC₅₀ values were also determined. The results showed that ‘amala’ flour had higher phenolic contents, reducing properties and DPPH radical scavenging ability while the raw flour had higher iron chelating and hydroxyl radical scavenging ability in a dose dependent manner and vitamin C (3.71mg/g) content. The ‘amala’ flour had higher α-amylase and α-glucosidase inhibitory activities than raw flour. The extracts had stronger inhibitory effects on α-glucosidase than α-amylase activities. The raw flour had higher ACE inhibitory activity (EC₅₀=0.81±1.39 mg/mL). These suggest their potential use in the management of type-2 diabetes and hypertension. This study evaluates the in vitro anti-oxidant activities inhibitory effects of aqueous extracts of unripe plantain on enzymes associated with type 2 diabetes.

Key words: Musa paradisiacal, type 2 diabetes, α-amylase, α-glucosidase, angiotensin-1-converting enzyme (ACE), hypertension, anti-oxidant.