Nutritional, elemental, antioxidant and inhibitory potential of three tropical leafy vegetables against α-amylase and α-glucosidase

Leafy vegetables are prominent component of nutrition serving as prominent sources of vitamins, minerals and protein. They offer protection against chronic ailments. In this study, nutritional, elemental, and bioactive compositions of three leafy vegetables (Amaranthus hybridus AH, Clerodendrum volubile CV and Corchorus olitorius CO) were investigated. Their antioxidant and α-amylase and α-glucosidase enzymes inhibitory potentials were also determined. The results showed that AH had the highest ash (8.12 ± 0.08 g/100 g), fibre (10.83 ± 0.10 g/100 g), carbohydrate (50.27 ± 1.16 g/100 g) and moisture (8.46 ± 0.25 g/100 g) contents while CO had the highest protein (30.24 ± 0.23 g/100 g) and fat (3.33 ± 0.11 g/100 g) contents. Minerals analyses showed that AH had the highest magnesium (1.26 ± 0.01 g/100 g), potassium (2.04 ± 0.01 g/100 g) and zinc (185.87 ± 4.51 ppm) contents, CO had the highest phosphorus (0.46 ± 0.01 g/100 g), calcium (1.83 ± 0.02 g/100 g), iron (2196.33 ± 5.67 ppm) and copper (14.12 ± 0.09 ppm) contents while CV had the highest contents of manganese (825.33 ± 8.02 ppm) and sodium (1.17 ± 0.02 g/100 g). Also, AH had the highest phenolics content (23.66 mg GAE/100 g), CV had highest flavonoids (9.82 mg QUE/100 g) and total antioxidant capacity (4.91 mg AAE/100 g) while CO had the highest ferric reducing antioxidant potential (35.12 mg Fe²⁺/100 g). Inhibitory potentials revealed CV had the highest against α-amylase (IC₅₀ = 462.50 µg/mL) and α-glucosidase (IC₅₀ = 393.85 µg/mL) enzymes and CO had highest against DPPH (IC₅₀ = 615.50 µg/mL). This study justifies the uses of these leafy vegetables as sources of nutrients and nutraceuticals and therefore can be used to prevent nutritional and chronic diseases.