Antioxidative properties and inhibition of key enzymes linked to type-2 diabetes by snake tomato (Tricosanthes cucumerina) and two tomato (Lycopersicon esculentum) varieties

Abstract

This study sought to compare the antioxidant properties [1,1-diphenyl-2 picrylhydrazyl (DPPH) and hydroxyl (OH) radicals scavenging abilities] and inhibition of Fe 2+-induced lipid peroxidation and two key enzymes relevant to type-2 diabetes (α-amylase and α-glucosidase) of snake tomato (Trichosanthes cucumerina) with two tomato varieties [Lycopersicon esculentum Mill. var. esculentum (ESC) and Lycopersicon esculentum Mill. var. cerasiforme (CER)]. Snake tomato (0.84 mg/g) and CER (0.87 mg/g) had significantly (P < 0.05) higher total phenolic content than ESC (0.27 mg/g). However, CER had the highest total flavonoid content of 0.48 mg/g, compared to snake tomato (0.27 mg/g) and ESC (0.15 mg/g). In consonance with the phenolic content, CER and snake tomato had higher DPPH and OH radicals scavenging abilities than ESC. The inhibition of Fe 2+ induced malondialdehyde (MDA) production in rats pancreas revealed that snake tomato had significantly lower inhibitory effect than CER. Furthermore, snake tomato and CER showed stronger inhibition of α-glucosidase [snake tomato (EC 50 = 1.65 mg/ml), CER (EC 50 = 1.32 mg/ml)] than α-amylase [snake tomato (EC 50 = 2.15 mg/ml), CER (EC 50 = 2.39 mg/ml)] activity. The antioxidant properties of snake tomato favourably compared with the cultivars of tomatoes, and its stronger inhibition of α-glucosidase activity than α-amylase activities suggests that snake tomato could be an alternative or complement to the use of lycopersicon tomatoes.