Effects and mechanism of Morus alba L. (Sangzhi) alkaloids combined with metformin on glucose metabolism in diabetic KKAy mice / 药学学报

To investigate the effects and mechanism of the combination of Morus alba L. (Sangzhi) alkaloids(SZ-A) and metformin (Met) on glucose metabolism in type 2 diabetic mice, KKAy mice were divided into four groups according to the glucose and lipid indexes: control group (control), Morus alba L. (Sangzhi) alkaloids group (SZ-A, 100 mg·kg-1), metformin group (Met, 100 mg·kg-1) and combined administration group (combination, Comb, 100 mg·kg-1 SZ-A + 100 mg·kg-1 Met). All groups were administered by gavage once daily for 7 weeks accompanied with monitoring food intake, water intake, body weight as well as glycemia. Additionally, oral glucose tolerance test (OGTT), insulin tolerance test (ITT) and oral sodium pyruvate tolerance test (OPTT) were performed at week 2, week 5, week 6, respectively. The experiments were approved by the Institutional Animal Care and Use Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College (00004332). We determined the weight and lipid content of liver, and then performed the histopathological analysis after sacrificed. Furthermore, Western blot assay was used to detect the protein levels of key molecules of PI3K/PDK1/Akt/GLUT signaling pathway in liver, muscle and adipose tissue. Compared to the SZ-A or Met monotherapy group, SZ-A + Met significantly improved the glucose metabolism disorder, which was showed in reduced food intake, water intake, the level of fasting blood glucose, postprandial blood glucose and glycosylated hemoglobin A1c (HbA1c) of KKAy mice, as well as improved glucose tolerance, enhanced insulin sensitivity and inhibited gluconeogenesis. In addition, SZ-A + Met obviously up-regulated the protein expression levels in PI3K/PDK1/Akt/GLUT signaling pathway in liver, muscle and adipose tissue of KKAy mice. Moreover, the liver lipid accumulation and blood aminotransferase level of KKAy mice in the combined administration group were significantly reduced. Therefore, we concluded that the combination of SZ-A and Met improved glucose metabolism and inhibited the occurrence and development of T2DM via promoting glucose uptake and utilization, suggesting that the combination of SZ-A and Met is a more useful treatment for T2DM.

Efficacy and Safety of Mulberry Twig Alkaloids Tablet for Treatment of Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled Multicenter Clinical Study / 中国结合医学杂志

OBJECTIVE@#To assess the efficacy and safety of mulberry twig alkaloids (Sangzhi alkaloids, SZ-A) for treatment of type 2 diabetes in a randomized, double-blind, placebo-controlled multicenter clinical trial.@*METHODS@#A total of 200 patients were randomized to receive SZ-A (n=100) or placebo (n=100) for 16 weeks. The data analysis system for electronic data capture clinical trial central randomization system was used for randomization and dispensing of drugs. The primary outcome was the change in glycosylated hemoglobin (HbA1c) level. The secondary outcome included the proportions of cases with HbA1c <7.0% and HbA1c <6.5%, fasting blood glucose (FBG), postprandial blood glucose (PBG), area under curve for the PBG (AUC0-2h), body weight, and body mass index (BMI). Adverse events (AEs), severe adverse events (SAEs), treatment-related adverse events (TAEs), gastrointestinal disorders (GDs), blood pressure, routine blood tests, and liver and kidney function were monitored.@*RESULTS@#Compared with baseline, the change of HbA1c at week 16 was -0.80% (95% CI: -0.98% to -0.62%) and -0.09% (95% CI: -0.27% to 0.09%) in SZ-A group and placebo group, respectively. The proportion of patients with HbA1c <7% and <6.5% was higher in the SZ-A group than in the placebo group (46.8% vs. 21.6% and 29.9% vs. 10.8%). The observed values and changes in FBG, 1 h-PBG, 2 h-PBG, and AUC0-2h differed significantly between groups (P<0.001), but differences were not significant in body weight and BMI (P>0.05). The incidence rates of AEs, TAEs, and GDs differed significantly between groups (P=0.010, P=0.005, and P=0.006, respectively), whereas the incidence rates of SAEs showed no significant differences between groups (P=1.000).@*CONCLUSION@#SZ-A are effective and safe for treatment of type 2 diabetes. The protocol was registered in http://www.chictr.org.cn/showproj.aspx?proj=60117 (ChiCTR2000038550).

Anti-diabetic effects of the fraction of alkaloids from Ramulus Mori, an innovative Sangzhi alkaloids as an α-glucosidase inhibitor / 药学学报

Sangzhi alkaloids (SZ-A) are derived from traditional Chinese medicine Ramulus Mori, serving well as an innovative antidiabetic drug, due to α-glucosidase inhibition. To evaluate the potency of glucosidase inhibitory effect of SZ-A, the enzyme-based screening platforms, including sucrase, maltase and amylase were established, and IC50 was calculated. The effects of SZ-A on postprandial blood glucose at a single dose, oral sucrose, starch and glucose loading were determined in normal ICR mice and alloxan-induced hyperglycemic mice. To confirm the anti-diabetic effects of SZ-A on glucose and lipid metabolism after long-term administration, the postprandial and fasting blood glucose, serum insulin, urinary glucose levels, glycosylated serum proteins and blood lipid levels were determined in high-fat fed C57 obese mice (pre-diabetic HFC57 mice) and diabetic rats induced by streptozotocin (STZ). The Experimental Animal Welfare Ethics Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College approved all of the protocols for this research. We found that SZ-A exhibited a significant inhibitory effect on the sucrase and maltase. SZ-A showed no effect on amylase. In normal ICR mice and alloxan-induced hyperglycemic mice, SZ-A at a single dose significantly delayed and reduced the peak of blood glucose after sucrose or starch loading, but showed no effect on the increase of blood glucose after glucose loading. In STZ diabetic rats, SZ-A significantly reduced the postprandial or fasting blood glucose levels, glycosylated serum proteins and urinary glucose. SZ-A also reduced serum triglyceride (TG) and cholesterol (TC) levels after 3 weeks of treatment. SZ-A ameliorated the postprandial blood glucose or the fasting blood glucose elevation, and reduced the incidence of hyperglycemia in HFC57 mice. SZ-A decreased the basal insulin level, improved insulin sensitivity, and ameliorated glucose intolerance in pre-diabetic HFC57 mice. Our results indicated that SZ-A had a novel inhibitory activity on α-glucosidase, especially on disaccharidases. SZ-A at a single dose significantly reduced the peak of blood glucose elevation and delayed the increase of blood glucose in normal and diabetic mice after disaccharide and polysaccharide loading. Long-term SZ-A treatment improved glucose and lipid metabolic profiles by delaying carbohydrate absorption from the intestine and reduced the postprandial blood glucose levels in both pre-diabetic and diabetic animal models. Therefore, SZ-A application may display a beneficial role in preventing the development and complications of diabetes.