Sustained-release effect of Na-montmorillonite on 1-deoxynojirimycin in alkaloid fraction of mulberry leaf extract / 中国药学杂志

OBJECTIVE: To investigate the sustained-release ability of Na-montmorillonite (Na-MMT) on 1-deoxynojirimycin (DNJ) in mulberry leaf extract (MLE). METHODS: In order to prepare DNJ-MMT composite, DNJ was intercalated into the inter-layer of MMT by stirring. Time and temperature for adsorption and ratio of DNJ to MMT were determined by calculating the loading of DNJ, then in vitro release experiment was carried out to estimate the sustained-release characteristics of DNJ-MMT. RESULTS: DNJ-MMT composite with a drug loading of 111.64 mg·g-1 was obtained by stirring 5.00 g Na-MMT and 16.00 g MLE containing 4016.0 mg DNJ in 1000 mL deionized water at 100℃ for 1 h. The composite released DNJ quickly in water, potassium phosphate buffer (pH 7.4), and 0.1 mol·L-1 hydrochloric acid solution. With the increasing of volume of hydrochloric acid solution, the release ratio of DNJ also increased correspondingly. CONCLUSION: The sustained-release effect of Na-MMT on DNJ is proved. Na-MMT can be used for study of DNJ sustained-release preparations.

Influence of mulberry leaf extract on serum adiponectin, visfatin and lipid profile levels in type 2 diabetic rats

ABSTRACT The effect of ethanolic mulberry leaf extract (MLE) and mulberry leaf powder (MLP) on glycemic control, serum adiponectin, visfatin and lipid profile in type2 diabetic rats have been investigated. 30 male wistar rats randomly divided into 5 groups. One group was randomly assigned as control (I) and diabetes was induced in others by administration of streptozotocin (STZ) (55 mg/kg body weight) 15 minutes after the administration of nicotinamide (110 mg/kg body weight) intraperitoneally. Finally, fasting blood glucose (FBG), lipid profile, adiponectin and visfatin were assessed after 6 weeks. Lipid profiles including serum FBG, total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-c), very low-density lipoprotein cholesterol (VLDL) and visfatin significantly decreased and high-density lipoprotein cholesterol (HDL-c) and adiponectin increased in the two groups of treated diabetic rats in comparison to the diabetic control (p<0.05). For all the investigated factors, there was no significant difference between two treatment methods. However, MLP was more effective than MLE in improving visfatin. Results showed that MLE and MLP possess hypoglycemic and hypolipidemic activities and play an important role in regulating the secretion of adipokines such as adiponectin and visfatin.

Anti-adipogenic effect of mulberry leaf ethanol extract in 3T3-L1 adipocytes

BACKGROUND/OBJECTIVES: Adipogenesis is part of the cell differentiation process in which undifferentiated fibroblasts (pre-adipocytes) become mature adipocytes with the accumulation of lipid droplets and subsequent cell morphological changes. Several transcription factors and food components have been suggested to be involved in adipogenesis. The aim of this study was to determine whether mulberry leaf ethanol extract (MLEE) affects adipogenesis in 3T3-L1 adipocytes. MATERIALS/METHODS: The 3T3-L1 adipocytes were treated with different doses of MLEE for 8 days starting 2 days post-confluence. Cell viability, fat accumulation, and adipogenesis-related factors including CCAAT-enhancer-binding protein alpha (C/EBPalpha), peroxisome proliferator-activated receptor gamma (PPARgamma), PPARgamma coactivator 1 alpha (PGC-1alpha), fatty acid synthase (FAS), and adiponectin were analyzed. RESULTS: Results showed that MLEE treatments at 10, 25, 50, and 100 microg/ml had no effect on cell morphology and viability. Without evident toxicity, all MLEE treated cells had lower fat accumulation compared with control as shown by lower absorbances of Oil Red O stain. MLEE at 50 and 100 microg/ml significantly reduced protein levels of PPARgamma, PGC-1alpha, FAS, and adiponectin in differentiated adipocytes. Furthermore, protein level of C/EBPalpha was significantly decreased by the treatment of 100 microg/ml MLEE. CONCLUSION: These results demonstrate that MLEE treatment has an anti-adipogenic effect in differentiated adipocytes without toxicity, suggesting its potential as an anti-obesity therapeutic.

Postprandial hypoglycemic effect of mulberry leaf in Goto-Kakizaki rats and counterpart control Wistar rats

Postprandial hypoglycemic effect of mulberry leaf (Morus alba L.) was compared in two animal models: Goto-Kakizaki (GK) rats, a spontaneous non-obese animal model for type II diabetes, and their counterpart control Wistar rats. First, the effect of a single oral administration of mulberry leaf aqueous extract (MLE) on postprandial glucose responses was determined using maltose or glucose as substrate. With maltose-loading, MLE reduced peak responses of blood glucose significantly in both GK and Wistar rats (P < 0.05), supporting the inhibition of alpha-glucosidase by MLE in the small intestine. With glucose-loading, MLE also significantly reduced blood glucose concentrations, measured at 30 min, in both animal models (P < 0.01), proposing the inhibition of glucose transport by MLE. Next, dried mulberry leaf powder (MLP) was administered for 8 weeks by inclusion in the diet. By MLP administration, fasting blood glucose was significantly reduced at weeks 4 and 5 (P < 0.05), but then returned to values that were similar to those of the control at the end of experimental period in GK rats. Insulin, HOMA-IR, C-reactive protein, and triglycerides tended to be decreased by MLP treatment in GK rats. All other biochemical parameters were not changed by MLP administration in GK rats. Collectively, these findings support that MLE has significant postprandial hypoglycemic effect in both non-obese diabetic and healthy animals, which may be beneficial as food supplement to manage postprandial blood glucose. Inhibitions of glucose transport as well as alpha-glucosidase in the small intestine were suggested as possible mechanisms related with the postprandial hypoglycemic effect of MLE.