<p>Evaluation of in vitro and in vivo Anti-Diabetic, Anti-Hyperlipidemic and Anti-Oxidant Activity of Flower Crude Extract and Solvent Fractions of <em>Hagenia Abyssinica</em> (Rosaceae)</p>

Abstract

Background: The flower of Hagenia abyssinica (Rosaceae) has been used in traditional health systems to treat diabetes mellitus in Ethiopia and Tanzania. However, the antidiabetic activity of this medicinal plant is not scientifically validated and authenticated. The present study aimed to investigate the in vitro and in vivo anti-diabetic activity of flower crude extract and solvent fractions of Hagenia abyssinica. Methods: The in vitro α-amylase inhibition and antioxidant activity of the crude extract and solvent fractions of Hagenia abyssinica were evaluated by using 3,5-dinitrosalicylic acid (DNSA) and diphenyl-2-picrylhydrazyl (DPPH) assay model, respectively. Blood glucose lowering activity of 80% methanolic flower crude extract and solvent fraction was studied in four animal models: normoglycemic mice model, oral glucose loaded mice model, single dose-treated streptozotocin-induced diabetic mice model, and repeated dose-treated streptozotocin-induced diabetic mice model. The effect of the crude extract and solvent fraction of Hagenia abyssinica on diabetic lipid profile and body weight was also studied. Results: The acute toxicity study of Hagenia abyssinica flower extract did not show mortality in the animals at the limit dose of 2g/kg during the observation period. The result of α-amylase enzyme inhibition activity was found in a dose-dependent manner, the strongest activity was shown by ethyl acetate fraction (54.23% inhibition at 800 μg/mL) compared to the standard acarbose having 91.87% inhibition at 800 μg/mL. Among these extracts, the crude extract had the highest antioxidant activity (58.38% inhibition at 500 μg/mL). The crude extract of H. abyssinica showed significant blood glucose-lowering effect on normoglycemic mice and oral glucose loaded mice. In streptozotocin-induced diabetic mice model, the crude extract and ethyl acetate fraction significantly decreased the fasting blood glucose level after 14 days of treatment. There were significant reductions in serum total cholesterol, serum triglycerides, very low-density lipoprotein, and low-density lipoprotein. However, there were significant increments in body weight and high-density lipoprotein as compared to untreated diabetic mice. Conclusion: The result demonstrated the beneficial biochemical effects of Hagenia abyssinica extract by inhibiting α-amylase, scavenging diphenyl-2-picrylhydrazyl (DPPH) and improving serum lipid profile levels. The flower crude extract and solvent fractions of Hagenia abyssinica are effective in lowering blood glucose levels in diabetic and normoglycemic mice. The claimed traditional use as antidiabetic has scientific ground.

<p>Hypoglycemic, Anti-Hyperglycemic and Anti-Hyperlipidemic Effects of <em>Bersama abyssinica Fresen</em> (Melianthaceae) Leaves’ Solvent Fractions in Normoglycemic and Streptozotocin-Induced Diabetic Mice</p>

“…The current findings are in agreement with previously reported similar studies. [40][41][42] After oral administration of B. abyssinica solvent fractions at all tested doses (100mg/kg, 200mg/kg and 400mg/ Notes: The result presented as mean ± SEM; n=6 for each group. a Compared to the diabetic control, n compared to the normal control, and β compared to baseline bodyweight.…”

“…The current finding is in agreement with previous similar studies. 41,46 This indicates that the solvent fractions showed its effect in a dose-dependent manner, the difference between the three doses might be because of the higher doses of the solvent fractions contains higher amounts of phytoconstituents responsible for more reduction of the fasting BGL than the lower doses of the solvent fractions. Similarly, glibenclamide reduces the fasting BGL by blockage of ATP sensitive K+ (KATP) channels, leads to membrane depolarization, activate voltage-gated Ca2+ channels, a rise in cytosolic (Ca2+), and then release of insulin in the pancreas.…”

“…This result is consistent with previous similar studies. 41,42,54 Abnormalities in lipid profiles are common complications in diabetes mellitus. In addition to its antihyperglycemic effect, an aqueous fraction of B. abyssinica was also able to alter the levels of serum lipid levels such as TC, TG, HDL, VLDL, and LDL cholesterol levels in diabetic mice suggesting a remarkable anti-hyperlipidemic effect.…”

In Vitro α‐Amylase and α‐Glucosidase Inhibitory and Antioxidant Activities of the Crude Extract and Solvent Fractions of Hagenia abyssinica Leaves

“…The preparation of the plant extract and solvent fractionations were done according to the method described by Kifle et al [ 32 ]. The leaves of H. abyssinica were thoroughly washed with distilled water to remove dirt and dried at room temperature (25–27°C).…”

“…The α -amylase inhibition activity was done according to the method described by Kifle et al [ 32 ]. The extract of H. abyssinica was dissolved in buffer ((NaCl (0.006 M), Na 2 HPO 4 /NaH 2 PO 4 (0.02 M)) at pH 6.9 to make the concentrations (15.625 to 500 μ g/ml).…”