Anti-Diabetic Effects of Allium hookeri Extracts Prepared by Different Methods in Type 2 C57BL/J- db/db Mice

Abstract

This study was conducted to evaluate whether Allium hookeri can control diabetic symptoms. Aqueous extract (AE1: 100 mg/kg BW, AE2: 200 mg/kg BW) and ethanol extract (EE1: 100 mg/kg BW, EE2: 200 mg/kg BW) of A. hookeri were orally administrated to diabetic mice (C57BL/J-db/db) for 8 weeks. The negative (NC) and the positive (PC) control groups were treated with 0.9% saline and metformin (150 mg/kg BW), respectively. Glucose and lipid profile (triglyceride, total cholesterol (TC), LDL-C, and HDL-C) as biochemical parameters, toxicological factors such as liver/kidney functional parameters (ALT, AST, BUN, and Cr), and NK cell activity in blood were measured. Oral glucose tolerance test (OGTT) and histopathological examination were also conducted. Compared with the NC group, AE and EE decreased blood glucose, HbA1c, area under the curve (AUC) during OGTT, and leptin levels while increasing adiponectin levels. Serum lipid profiles and toxicological factors levels were reduced by the A. hookeri extract. Interestingly, HDL-C, glomerular mesangial expansion score in the kidney, and NK cell activity were effectively controlled in EE groups. Based on the results, EE is considered to be more effective in reducing high blood glucose, lipid profile, and related factor levels than AE, and is comparable to metformin in some biomarkers. It can be presumed that EE can more effectively control the major anomalies in the diabetic model than AE, and it may be used to prevent diabetic symptoms without toxicity in the Type 2 diabetic model.

Keywords: Allium hookeri; diabetes; glucose; immunity; lipid.

Figure 1

Chromatograms of cycloalliin in (a) standard, (b) aqueous, and (c) ethanol extracts of A. hookeri analyzed by LC/MS.

Figure 2

Effects of A. hookeri extracts on fasting blood glucose levels in the diabetic mice. Control: non-diabetic mice; NC: negative control; PC: positive control, metformin 150 mg/kg BW; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with A. hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8). ^a–e Mean values with different letters are significantly different at p < 0.05.

Figure 3

Effects of A. hookeri extracts on the OGTT of the diabetic mice. (a) Blood glucose changes, (b) area under the curve (AUC). Control: non-diabetic mice; NC: negative control; PC: positive control, metformin 150 mg/kg BW; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with A. hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8). ^a–d Mean values with different letters are significantly different at p < 0.05.

Figure 4

Effects of A. hookeri extracts on (a) blood HbA1c, (b) serum insulin, (c) leptin, and (d) adiponectin levels in the diabetic mice. Control: non-diabetic mice; NC: negative control; PC: positive control, metformin 150 mg/kg BW; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with A. hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8). ^a–d Mean values with different letters are significantly different at p < 0.05.

Figure 5

Effects of A. hookeri extracts on toxicological factors in the serum of the diabetic mice. (a) ALT, (b) AST, (c) BUN, and (d) Cr. Control: non-diabetic mice; NC: negative control; PC: positive control, metformin 150 mg/kg BW; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with A. hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8). ^a–d Mean values with different letters are significantly different at p < 0.05.

Figure 6

Effects of A. hookeri extracts on serum lipid profile in diabetic mice. (a) Triglyceride, (b) TC, (c) LDL-C, and (d) HDL-C. Control: non-diabetic mice; NC: negative control; PC: positive control, metformin 150 mg/kg BW; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with A. hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8). ^a–c Mean values with different letters are significantly different at p < 0.05.

Figure 7

Effects of A. hookeri extracts on histopathological examination of the diabetic mice. Control: non-diabetic mice; NC: negative control; PC: positive control; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with Allium hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8).

Figure 8

Effects of A. hookeri extracts on (a) insulin immunoactivity score in the pancreas and on (b) glomerular mesangial expansion score in the kidney of the diabetic mice. Control: non-diabetic mice; NC: negative control; PC: positive control; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with Allium hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8). ^NS Not significantly different among groups. ^a–e Different letters mean values are considered statistically significant at p < 0.05.

Figure 9

Effects of A. hookeri extracts on NK activity in the blood of diabetic mice. Control: non-diabetic mice; NC: negative control; PC: positive control, metformin 150 mg/kg BW; AE1: aqueous extract 100 mg/kg BW; AE2: aqueous extract 200 mg/kg BW; EE1: ethanol extract 100 mg/kg BW; EE2: ethanol extract 200 mg/kg BW. AE and EE groups were treated with A. hookeri extracts for 8 weeks. Data are presented as the mean ± SEM (n = 8). ^a,b Mean values with different letters are significantly different at p < 0.05.