Screening of Manilkara zapota (L) P. Royen stem bark ethanolic extract for in vitro α-glucosidase inhibition, preliminary antidiabetic effects, and improvement of diabetes and its complications in alloxan-induced diabetes in Wistar rats

Abstract

Abstract Background A perusal of the literature suggested that Manilkara zapota (L.) P. Royen stem bark (MZSB) is enriched with several bioactive phytoconstituents but had not been yet screened for its in vitro and in vivo antidiabetic potentials. Thus, the present study aimed to investigate the effects of 70% ethanolic extract of Manilkara zapota (L) P. Royen stem bark (EMZSB) in DPPH- and H2O2-scavenging assay, in vitro α-glucosidase inhibition assay, ameliorating diabetes and its complications in alloxan-induced diabetes in Wistar rats. Results With a maximum extractive yield of 9.16% w/w, EMZSB has shown the presence of various phytochemicals like flavonoids, phenolic compounds, tannins, anthraquinone glycosides, steroids, terpenoids, and alkaloids. EMZSB has elucidated a considerable in vitro free radical scavenging potential by DPPH and H2O2 assays when compared with absolute ethanolic extract of Manilkara zapota (L) P. Royen stem bark (AEMZSB), while ascorbic acid was taken as the standard. Further, EMZSB demonstrated high in vitro α-glucosidase enzyme inhibition potential (IC50 = 119.79 ± 1.52 µg/mL) than AEMZSB (IC50 = 129.92 ± 2.29 µg/mL) with a significant difference (p < 0.01), when acarbose was taken as reference inhibitor (IC50 = 86.43 ± 1.26 µg/mL). During acute toxicity studies EMZSB was safe up to 2000 mg kg−1 doses while, found causing moribund status followed by mortality in mice at 3000 mg kg−1 and above doses. A preliminary antidiabetic study with EMZSB-250 mg kg−1 in normal rats showed no sign of hypoglycemia; however, a dose-dependent antihyperglycemic effects were observed in oral glucose tolerance test in glucose-loaded rats. In vivo assessment with EMZSB-250 mg kg−1 in alloxan-induced rats demonstrated significant blood glucose-lowering effects with perfection in serum lipid profile, body weight enhancement, cardiovascular risk indices, nephroprotective effects, augmentation in liver glycogen content, and histopathological evidence of normal architecture of kidneys with no marks for nephritis. Conclusions EMZSB-250 showed significant antidiabetic effects and ameliorated diabetic complications by improving glycemic control and accompanying biochemical alteration.