The antidiabetic properties of Uncaria gambir are not yet fully understood, particularly concerning how it affects diabetic animal models. Further investigation in this aspect is pivotal before initiating clinical evaluations. This study aimed to investigate the antidiabetic activity of U. gambir and how it influences blood glucose levels in diabetic Sprague–Dawley rats. In this study, 28 rats were divided into 7 groups. The groups were as follows: a nondiabetic rat group, a nondiabetic rat group given U. gambir, a diabetic rat group, a diabetic rat group given glibenclamide, and 3 diabetic rat groups given U. gambir at 3 doses (200, 300, and 400 mg/kg). Diabetes was induced using streptozotocin (50 mg/kg) given by intraperitoneal injection. Blood glucose levels were measured weekly, and the animals were euthanized at the end of the experiment. Intracardiac blood and tissues such as the pancreas, liver, and skeletal muscle were collected for further analysis. The results showed that administering U. gambir to diabetic rats resulted in significantly lower blood glucose levels than untreated diabetic rats. U. gambir has a complex mechanism to reduce blood glucose levels. including increase of insulin production, preservation of the islets and pancreatic β cells, and optimization of glycogenesis, as reflected in a significant increase in liver glycogen levels. These findings suggest that U. gambir’s multicompound and multitarget capabilities in controlling blood glucose levels may have utility for treatment of diabetes.Abstract
HPLC-UV-VIS quercetin profile of Uncaria gambir. (A) Quercetin in Uncaria gambir extract. (B) Quercetin standard. The red letter ‘q’ at the peak of the chromatogram indicates quercetin.
The effect of Uncaria gambir on blood glucose level. (A) Fluctuations in blood glucose levels during 28 d of observation. (B) AUC of glucose level. *Significant difference compared with the DM group according to the Dunnett test (P ≤ 0.05). DM, diabetes mellitus (DM); Glib, glibenclamide; UG, Uncaria gambir.
The effect of Uncaria gambir to insulin level. Different letters above the bar indicate significant differences according to the Duncan multiple range test (P ≤ 0.05). DM, diabetes mellitus; Glib, glibenclamide; UG, Uncaria gambir.
The effect of Uncaria gambir on islets of Langerhans and β cells. (A) Photomicrograph of immunohistochemical staining of insulin-activated pancreatic β cells; scale = 50 µm; 10 × 40 magnifications. (B) The proportion of β cells to the total number of cells. (C) The number of islets per high-powered field; 10 × 10 magnifications. Different letters above the bar indicate significant differences according to the Duncan multiple range test for the proportion of β cells or Mann-Whitney test for the number of islets (P ≤ 0.05). Arrows are pancreatic β-cell representation. DM, diabetes mellitus; Glib, glibenclamide; L, islet of Langerhans; UG, Uncaria gambir.
The effect of Uncaria gambir on liver glycogen. (A) Photomicrograph of PAS staining of liver glycogen; scale = 50 µm. (B) Quantitative liver glycogen intensity per high-powered field; 10 × 40 magnifications. Different letters above the bar indicate significant differences according to the Duncan multiple range test (P ≤ 0.05). CV, central vein; DM, diabetes mellitus; Glib, glibenclamide; UG, Uncaria gambir.
The effect of Uncaria gambir on skeletal muscle glycogen. (A) Photomicrograph of PAS staining of skeletal muscle glycogen; scale = 50 µm. (B) Quantitative skeletal muscle glycogen intensity. DM, diabetes mellitus; Glib, glibenclamide; ns, not significant; UG, Uncaria gambir.
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