RESUMO
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.
RESUMO
Solid dispersions technique was used to solidify buagafuran and improve buagafuran in vitro dissolution and stability. Buagafuran solid dispersions were prepared separately using PVPK30, PEG6000 and Poloxamer188 at various weight ratios as carriers. The status of buagafuran in solid dispersions was determined by using DSC and IR. The solubility, content and in vitro dissolution of pure drug and the solid dispersions were detected by using HPLC. When buagafuran/carrier was 1:5 or less, the drug existed in a solid dispersion form. Three kinds of carriers all can improve buagafuran dispersibility and in vitro dissolution. Accelerating experiment showed that buagafuran/PVPK30 < or = 1:10 solid dispersions was ageing-resistant, and the aspect, content and in vitro dissolution did not change after storaged over 3 months, but PEG6000, Poloxamer188 and a lower ratio PVPK30 solid dispersions became aged. Buagafuran/PVPK30 < or = 1:10 solid dispersions can be developed as buagafuran oral drug delivery carrier.