The study was designed to investigate the ameliorative effect of phytochemicals in the extract of Justicia secunda (JS) on hyperglycaemia, the antioxidant status of alloxan-induced diabetic rats, and inhibitory potential on two important diabetes mellitus-associated proteins-alpha-amylase and alpha-glucosidase. At the same time to evaluate the anti-arthritic and antibacterial of the sample. The extract at doses of 200 mg/kg and 400 mg/kg was used to evaluate hyperglycaemia and antioxidants using the albino rats model. There was a significant decrease (p < 0.05) in blood insulin concentration levels observed in the diabetic control group relative to normal control, while treated groups showed relatively normal concentration levels. A significant increase (p < 0.05) in blood glucose concentration levels was observed in the diabetic control group relative to the normal control. There was a reversal of the elevated blood glucose upon treatment with JS when compared to the diabetic control. There was a significant decrease (p < 0.01) in Malondialdehyde (MDA) levels in all test groups relative to the diabetic control group. Glutathione (GSH) status, Glutathione S-transferase (GST) and catalase activities showed a significant increase in all test groups, relative to diabetic control. It was observed that 3,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one, and 3-amino-4-methoxybutyric acid are potential inhibitors of alpha-amylase while 1-(1-adamantyl)-3-(dimethylamino)-1-propanone, 2-(2-hydroxypropyl)-1,4-benzenediol, and 3-amino-4-methoxybutyric acid are potential inhibitors of alpha-glucosidase. Interestingly, phytochemicals in JS were shown to be a stable dual inhibitor of both α-amylase and α-glucosidase. Anti-arthritic potential values were ranged between 24.50-80.00%. The Zone of inhibition in the antibacterial assay was between 0.7-30.0 mm. Galvinoxyl and DPPH IC50 values of the extract were 50.0 µgml-1 each. The results of this study showed that the leaf of Justicia secunda possesses phytochemicals that significantly reduce blood glucose and ameliorate oxidative stress evidenced in diabetic rats. This plant may therefore serve as an excellent alternative therapy for the management of diabetes mellitus, arthritic and bacterial-related health problems and be formulated food or drug supplement.
