Acarbose and nutrient intake in non-insulin dependent diabetes mellitus

In Vitro Anti-Diabetic Activities and UHPLC-ESI-MS/MS Profile of Muntingia calabura Leaves Extract

Anti-diabetic compounds from natural sources are now being preferred to prevent or treat diabetes due to adverse effects of synthetic drugs. The decoction of Muntingia calabura leaves was traditionally consumed for diabetes treatment. However, there has not been any published data currently available on the processing effects on this plant’s biological activity and phytochemical profile. Therefore, this study aims to evaluate the effect of three drying methods (freeze-drying (FD), air-drying (AD), and oven-drying (OD)) and ethanol:water ratios (0, 50, and 100%) on in vitro anti-diabetic activities of M. calabura leaves. In addition, an ultrahigh-performance-liquid chromatography–electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method was used to characterize the metabolites in the active extract. The FD M. calabura leaves, extracted with 50% ethanol, is the most active extract that exhibits a high α-glucosidase and α-amylase inhibitory activities with IC₅₀ values of 0.46 ± 0.05 and 26.39 ± 3.93 µg/mL, respectively. Sixty-one compounds were tentatively identified by using UHPLC-ESI-MS/MS from the most active extract. Quantitative analysis, by using UHPLC, revealed that geniposide, daidzein, quercitrin, 6-hydroxyflavanone, kaempferol, and formononetin were predominant compounds identified from the active extract. The results have laid down preliminary steps toward developing M. calabura leaves extract as a potential source of bioactive compounds for diabetic treatment.

Is there a role for alpha-glucosidase inhibitors in the prevention of type 2 diabetes mellitus?

Type 2 diabetes mellitus is a major health problem associated with excess morbidity and mortality. As the prevalence of this metabolic disorder is rapidly increasing and current treatment fails to stabilise the disease in most patients, prevention should be considered as a key objective in the near future. People who develop type 2 diabetes pass through a phase of impaired glucose tolerance (IGT). Defects in the action and/or secretion of insulin are the two major abnormalities leading to development of glucose intolerance. Any intervention in the impaired glucose tolerance phase that reduces resistance to insulin or protects the beta-cells, or both, should prevent or delay progression to diabetes.Acarbose, miglitol and voglibose act by competitively inhibiting the alpha-glucosidases, a group of key intestinal enzymes involved in the digestion of carbohydrates. They decrease both postprandial hyperglycaemia and hyperinsulinaemia, and thereby may improve sensitivity to insulin and release the stress on beta-cells. These compounds do not induce hypoglycaemia and have a good safety profile, although gastrointestinal adverse effects may limit long-term compliance to therapy. The recent placebo-controlled prospective STOP-noninsulin-dependent diabetes mellitus (STOP-NIDDM) trial demonstrated that acarbose 100mg three times daily reduces the risk of developing type 2 diabetes in patients with IGT (relative risk reduction of 25% after a mean follow-up of 3.3 years). The 6-year Early Diabetes Intervention Trial (EDIT), comparing the effect of acarbose 50mg three times daily to that of metformin, showed a trend to a positive effect of acarbose compared with placebo, in a mid-term 3-year analysis, which should be confirmed in the final analysis. To our knowledge, no such prevention intervention trials have been or are currently being performed with miglitol or voglibose. In conclusion, because of its absence of toxicity and its particular mechanism of action on gastrointestinal tract and indirect consequences on both insulin action and beta-cell function, acarbose may be used to prevent type 2 diabetes. If the ongoing EDIT trial confirms the positive results of the recent STOP-NIDDM trial, acarbose could be used, either as an alternative or in addition to changes in lifestyle, to delay development of diabetes in patients with IGT. However, the best dosage of acarbose for this specific indication remains to be specified, especially when all three important parameters, efficacy, tolerance and cost, are taken into consideration.

Control of postprandial hyperglycaemia by galactosyl maltobionolactone and its novel anti-amylase effect in mice

The ability to control carbohydrate digestion is useful in the treatment of diabetes mellitus and obesity. In the present study, we examined whether recently developed 4(2)-O-beta-D-galactosyl maltobionolactone (LG2O) having anti-amylase activity is able to control postprandial blood glucose concentration in mice. In addition, we tried to determine how LG2O regulates carbohydrate delivery in the gut lumen by conducting in vivo and in vitro studies. Male non-diabetic ddY mice and KK-A(y) mice, a spontaneously diabetic strain, had free access to a carbohydrate rich diet supplemented with LG2O (3 or 10 g/kg) for 0.5 hr, and blood glucose concentration was measured. LG2O suppressed any steep increase in postprandial blood glucose concentration in both ddY and KK-A(y) mice. Corresponding to the blood glucose response, LG2O also markedly suppressed any increase in postprandial plasma insulin concentration. After ingestion of the diet, LG2O produced a 1.5-3.5 fold increase in the gut contents and reducible sugar content in the small intestine but not in the stomach. Although alpha-amylase activity in the stomach was much lower compared with the activity in the small intestine, LG2O still strongly inhibited alpha-amylase activity in the stomach. In contrast, LG2O had little or no influence on alpha-amylase activity in the proximal intestine. From the in vitro carbohydrate digestion stimulation, LG2O at 7.5 mM decreased glucose production by 75% for dextrin, 25% for alpha-starch and 60% for raw starch. In conclusion, administration of LG2O inhibits carbohydrate digestion in the gut, and produces significant improvements in both blood glucose and insulin response following ingestion as part of the diet, and this evidence provides support for its therapeutic potential in treating diabetes mellitus and obesity.

Effect of acarbose on weight maintenance after dietary weight loss in obese subjects

AIMS

Acarbose is a well established antidiabetic drug and is known to exert a modest weight-lowering effect. The aim of this study was to assess the potential of acarbose to improve weight maintenance after a substantial weight loss by dietary measures in obese subjects.

DESIGN

Randomised, double-blind, placebo-controlled trial of the effect of acarbose on weight change over a 6-month follow-up period.

PATIENTS AND METHODS

One hundred and ten obese subjects with a BMI > or = 32 and < or = 38 kg/m2 were included in the study and underwent a 10-16-week very-low-calorie diet programme to initiate weight loss. Then, subjects were randomised to receive either acarbose or placebo for 26 +/- 2 weeks. The primary variable was body weight. The primary efficacy analysis was performed in the per-protocol population (n = 75).

RESULTS

After an initial mean weight loss of 10.0 +/- 3.4 kg, 54 subjects received acarbose at increasing dosage and 56 subjects received placebo treatment. After 14 weeks of follow-up, there was no change in body weight in the two groups. After 26 weeks, completed by 37 subjects in the acarbose group and by 38 subjects in the placebo group, a small weight regain of 0.6 kg was documented in the latter, whereas no weight increase was observed under acarbose treatment (p = 0.38, analysis of covariance with initial body weight as covariable).

CONCLUSION

In obese individuals who undergo a hypocaloric diet and achieve a substantial loss of body weight, acarbose treatment provides only a very modest, not significant benefit to stabilise weight reduction. Thus, acarbose is not a useful adjunct to improve weight maintenance in obese subjects after weight loss.

Acarbose treatment does not change the habitual diet of patients with Type 2 diabetes mellitus. The Finnish Acargbos Study Group

AIMS

It has been speculated that acarbose treatment in patients with Type 2 diabetes mellitus might induce changes in diet as a result of its adverse gastrointestinal effects. The aim of this study was to determine whether poor metabolic control can be improved by acarbose, and whether this might be because the acarbose supplementation provokes changes in diet.

METHODS

Poorly controlled Type 2 diabetic patients treated with oral hypoglycaemic agents (OHA) were randomized into either acarbose (100 mg t.d.s.) or placebo treatment. The double-blind treatment lasted for 24 weeks. Four-day food diaries and blood samples for efficacy analysis were collected at 0, 4, 12, and 24 weeks. Thirty-six acarbose and 39 placebo-treated patients completed the trial and were included in the final analyses.

RESULTS

At 24 weeks the baseline adjusted means of fasting, 1 and 2-h postprandial blood glucose values were 9.3 vs. 10.5 (P=0.02), 11.6 vs. 14.5 (P<0.001) and 11.0 vs. 13.7 mmol/l (P<0.001) and HbA1 9.3% vs. 10.2% (P=0.002) in the acarbose and placebo groups, respectively. No significant differences in nutrient intakes between groups were observed. The energy intake and energy proportion of fat and carbohydrates remained unchanged in both groups.

CONCLUSIONS

Acarbose significantly improves metabolic control in Type 2 diabetic patients poorly controlled with oral hypoglycaemic agents. This effect seems not to be a result of concomitant involuntary dietary changes, since acarbose did not induce modifications in diet during the study.

Acarbose: its role in the treatment of diabetes mellitus

OBJECTIVES

To review the clinical pharmacology of acarbose, an alpha-glucosidase inhibitor, and to summarize its role in the pharmacotherapy of diabetes mellitus.

DATA SOURCES

A MEDLINE search identified all relevant articles, including reviews; Bayer Pharmaceuticals.

STUDY SELECTION

Due to the large number of clinical trials available, specific criteria were used to narrow the focus of this review: (1) randomized, double-blind, placebo-controlled, parallel-group study design; (2) a minimum of 25 patients enrolled per treatment arm; (3) a treatment duration of 90 days or more; and (4) adherence to Food and Drug Administration Good Clinical Practice guidelines.

DATA EXTRACTION

All clinical trials that were available up to December 1995 were reviewed. Preliminary trials and unpublished reports were not reviewed.

DATA SYNTHESIS

Acarbose is effective in reducing postprandial hyperglycemia. It does not stimulate endogenous insulin secretion and, therefore, will not cause hypoglycemia when used as monotherapy. The enhanced glycemic control achieved with acarbose is additive to that of sulfonylureas. It lowers postprandial serum glucose and insulin concentrations and does not promote weight gain. Acarbose can be used as first-line therapy with diet and exercise, or it can be used in combination with sulfonylureas to lower hemoglobin A1c concentrations an additional 0.5-0.9%. Acarbose is not a cure for diabetes, nor is it a substitute for diet, exercise, oral hypoglycemic agents, or insulin. Adverse effects are gastrointestinal and can be diminished by starting with an initial dosage of 25 mg tid. Depending on patient response, the dosage can be increased up to a maximum of 100 mg tid over time.

CONCLUSIONS

Acarbose, through its unique mechanism of action, appears to be a safe and effective adjunctive agent to diet/exercise therapy or sulfonylurea therapy for treatment of non-insulin-dependent diabetes mellitus.