A high dose of carob exhibits an in vivo antihyperglycemic activity. - GreenMedInfo Summary
Evaluation of the glycemic effect ofpods (Carob) on a streptozotocin-nicotinamide induced diabetic rat model.
PeerJ. 2018 ;6:e4788. Epub 2018 May 23. PMID: 29844959
Mousa A Qasem
Background: pods (carob) have been nominated to control the high blood glucose of diabetics. In Yemen, however, its antihyperglycemic activity has not been yet assessed. Thus, this study evaluated theinhibitory effect of the methanolic extract of carob pods againstα-amylase and α-glucosidase and theglycemic effect of such extract in streptozotocin-nicotinamide induced diabetic rats.
Methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric reducing antioxidant power assay (FRAP) were applied to evaluate the antioxidant activity of carob.cytotoxicity of carob was conducted on human hepatocytes (WRL68) and rat pancreaticβ-cells (RIN-5F). Acute oral toxicity of carob was conducted on a total of 18 male and 18 female(SD) rats, which were subdivided into three groups ( = 6), namely: high and low dose carob-treated (CS5000 and CS2000, respectively) as well as the normal control (NC) receiving a single oral dose of 5,000 mg kgcarob, 2,000 mg kgcarob and 5 mL kgdistilled water for 14 days, respectively. Alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, total bilirubin, creatinine and urea were assessed. Livers and kidneys were harvested for histopathology.inhibitory effect againstα-amylase and α-glucosidase was evaluated.glycemic activity was conducted on 24 male SD rats which were previously intraperitoneally injected with 55 mg kgstreptozotocin (STZ) followed by 210 mg kgnicotinamide to induce type 2 diabetes mellitus. An extra non-injected group ( = 6) was added as a normal control (NC). The injected-rats were divided into four groups ( = 6), namely: diabetic control (D0), 5 mg kgglibenclamide-treated diabetic (GD), 500 mg kgcarob-treated diabetic (CS500) and 1,000 mg kgcarob-treated diabetic (CS1000). All groups received a single oral daily dose of their treatment for 4 weeks. Body weight, fasting blood glucose (FBG), oral glucose tolerance test, biochemistry, insulin and hemostatic model assessment were assessed. Pancreases was harvested for histopathology.
Results: Carob demonstrated a FRAP value of 3191.67± 54.34 µmoL Feand ICof DPPH of 11.23± 0.47 µg mL.carob was non-toxic on hepatocytes and pancreaticβ-cells. In acute oral toxicity, liver and kidney functions and their histological sections showed no abnormalities. Carob exerted aninhibitory effect againstα-amylase and α-glucosidase with ICof 92.99 ± 0.22 and 97.13 ± 4.11 µg mL, respectively. In diabetic induced rats, FBG of CS1000 was significantly less than diabetic control. Histological pancreatic sections of CS1000 showed less destruction ofβ-cells than CS500 and diabetic control.
Conclusion: Carob pod did not cause acute systemic toxicity and showedantioxidant effects. On the other hand, inhibitingα-amylase and α-glucosidase was evident. Interestingly, a high dose of carob exhibits anantihyperglycemic activity and warrants further in-depth study to identify the potential carob extract composition.