Abrus precatorius Leaf Extract Reverses Alloxan/Nicotinamide-Induced Diabetes Mellitus in Rats through Hormonal (Insulin, GLP-1, and Glucagon) and Enzymatic (α-Amylase/α-Glucosidase) Modulation

Abstract

Background. Abrus precatorius is used in folk medicine across Afro-Asian regions of the world. Earlier, glucose lowering and pancreato-protective effects of Abrus precatorius leaf extract (APLE) was confirmed experimentally in STZ/nicotinamide-induced diabetic rats; however, the underlying mechanism of antidiabetic effect and pancreato-protection remained unknown. Objective. This study elucidated antidiabetic mechanisms and pancreato-protective effects of APLE in diabetic rats. Materials and Methods. APLE was prepared by ethanol/Soxhlet extraction method. Total phenols and flavonoids were quantified calorimetrically after initial phytochemical screening. Diabetes mellitus (DM) was established in adult Sprague-Dawley rats (weighing 120–180 g) of both sexes by daily sequential injection of nicotinamide (48 mg/kg; ip) and Alloxan (120 mg/kg; ip) over a period of 7 days. Except control rats which had fasting blood glucose (FBG) of 4.60 mmol/L, rats having stable FBG (16–21 mmol/L) 7 days post-nicotinamide/Alloxan injection were considered diabetic and were randomly reassigned to one of the following groups (model, APLE (100, 200, and 400 mg/kg, respectively; po) and metformin (300 mg/kg; po)) and treated daily for 18 days. Bodyweight and FBG were measured every 72 hours for 18 days. On day 18, rats were sacrificed under deep anesthesia; organs (kidney, liver, pancreas, and spleen) were isolated and weighed. Blood was collected for estimation of serum insulin, glucagon, and GLP-1 using a rat-specific ELISA kit. The pancreas was processed, sectioned, and H&E-stained for histological examination. Effect of APLE on enzymatic activity of alpha (α)-amylase and α-glucosidase was assessed. Antioxidant and free radical scavenging properties of APLE were assessed using standard methods. Results. APLE dose-dependently decreased the initial FBG by 68.67%, 31.07%, and 4.39% compared to model (4.34%) and metformin (43.63%). APLE (100 mg/kg) treatment restored weight loss relative to model. APLE increased serum insulin and GLP-1 but decreased serum glucagon relative to model. APLE increased both the number and median crosssectional area (×106μm2) of pancreatic islets compared to that of model. APLE produced concentration-dependent inhibition of α-amylase and α-glucosidase relative to acarbose. APLE concentration dependently scavenged DPPH and nitric oxide (NO) radicals and demonstrated increased ferric reducing antioxidant capacity (FRAC) relative to standards. Conclusion. Antidiabetic effect of APLE is mediated through modulation of insulin and GLP-1 inversely with glucagon, noncompetitive inhibition of α-amylase and α-glucosidase, free radical scavenging, and recovery of damaged/necro-apoptosized pancreatic β-cells.

Abrus precatorius Leaf Extract Stimulates Insulin-mediated Muscle Glucose Uptake: In vitro Studies and Phytochemical Analysis

“…An ethanolic APLE was shown to reduce fasting blood glucose levels (BGL) in rats with chemically induced diabetes [7,8]. The reduction in BGL was 69 % (100 mg/ kg extract) compared to a reduction of 44 % by 300 mg/kg metformin, and was accompanied by increased serum insulin and glucagon-like peptide 1 (GLP-1) levels, reduced glucagon levels, inhibition of α-amylase and α-glucosidase, and improved recovery of damaged pancreatic β cells [7]. Our findings support the in vivo antidiabetic activity of A. precatorius leaves and demonstrates that increased skeletal muscle glucose uptake via the Akt/PI3K pathway is a mechanism responsible for the blood glucose-lowering action of APLE.…”

“…Previous research by others has demonstrated antidiabetic activity of APLE in diabetic animals. An ethanolic APLE was shown to reduce fasting blood glucose levels (BGL) in rats with chemically induced diabetes [7,8]. The reduction in BGL was 69 % (100 mg/ kg extract) compared to a reduction of 44 % by 300 mg/kg metformin, and was accompanied by increased serum insulin and glucagon-like peptide 1 (GLP-1) levels, reduced glucagon levels, inhibition of α-amylase and α-glucosidase, and improved recovery of damaged pancreatic β cells [7].…”

“…The nutrient-rich leaves are used in the daily diet, and as a traditional medicine for the management of diabetes in parts of Africa [6,7]. A. precatorius leaf extracts have demonstrated antidiabetic activity in animal models [7,8]. However, the mechanistic details remain to be elucidated.…”

A Single Strain of Lactobacillus (CGMCC 21661) Exhibits Stable Glucose- and Lipid-Lowering Effects by Regulating Gut Microbiota

“…We separated retro-orbital blood into serum, and then detected total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), and the aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio [ 38 ]. We used the enzyme-linked aptamer sorbent assay (ELASA) kit to measure serum INS, GLP-1, DDP-4 and inflammatory factors (Interleukin-10 (IL-10), Tumour necrosis factor alpha (TNF-α)) [ 39 , 40 , 41 ]. For the test, specimens, standards and HRP-labeled antibodies are added to microtiter wells pre-covered with antibodies, followed by incubation, washing, and color development.…”

N-Acetyl Cysteine, Selenium, and Ascorbic Acid Rescue Diabetic Cardiac Hypertrophy via Mitochondrial-Associated Redox Regulators

“…Rats of both sexes were divided into 8 experimental groups and each group which comprised of 6 rats that were randomly divided at a ratio of 1:1 in each experimental group. The body weight of all animals ranged between (120 g–180 g) [ 78 , 79 ] and they ranged from 4–6 weeks old ( Figure 1 A). All animals were fed on normal feed and water.…”