In vivo antidiabetic and antioxidant potential of Psychotria dalzellii in streptozotocin-induced diabetic rats

Abstract

Psychotria species have been known for wide array of health benefits as per traditional knowledge and only a few scientific evidences are available. In the current study in vivo antidiabetic property of methanol extract of Psychotria dalzellii (MEPD) was elucidated in alloxan-induced type 1 diabetes in Wistar rats. MEPD, acetone and ethylacetate extracts were examined for potential anti-diabetic properties (α-amylase and α-glucosidase inhibition) in in vitro and the significantly potent extract – MEPD was analyzed for in vivo antioxidant activity. Blood glucose levels, TBARS, antioxidant, creatinine, alkaline phosphatase etc., were measured. Results of the study revealed that, oral intubation of 400 mg kg−1b.w. of MEPD for a period of 20 days prior inducing diabetes resulted in the normalization of blood glucose level (259.83 ± 10.11 mg/dL as opposed to induced 389.5 ± 8.97; healthy animals had 129.16 ± 4.12 mg/dL glucose) suggesting the antidiabetic potency of MEPD. Biochemical analysis substantiated the antidiabetic property of MEPD as revealed by normalization of altered TBARS/oxidant and antioxidant levels. Results were further substantiated by in vitro studies, where MEPD exhibited good antioxidant activity – reducing power activity (IC50–8.81 U/mg vs Ascorbic acid – 6.21 U/mg; MEPD); hydrogen peroxide activity (IC50−26.57 μg/mL vs Ascorbic acid 19.12 μg/mL); MEPD inhibited α-amylase and α-glucosidase activity with (IC50 47.11 ± 2.8 μg/mL vs Acarbose – IC50 40.86 ± 1.7 μg/mL); (IC50 40.34 ± 1.2 μg/mL vs Acarbose – IC50 40.99 ± 2.3 μg/mL); providing evidence for the first time for the antidiabetic property of P. dalzellii. The potent anti-type I diabetic property could be due to antioxidant and inhibition of α-glucosidase/amylase which results in control of release of glucose levels into the circulation. Phytochemical analysis of revealed that MEPD is enriched in phenolics and flavonoids compound. In order to understand its probable mechanism of action, antioxidant status during healthy, diabetic and sample treated groups of animals were also investigated.