cucurbitane and Diabetes-Mellitus--Type-2

Luohanguo (LHG), a traditional Chinese medicine, could clear heat, moisten the lung, soothe the throat, restore the voice, and lubricate intestine and open the bowels. LHG has been utilized for the treatment of sore throats and hyperglycemia in folk medicine as a homology of medicine and food. The hypoglycemic pharmacology of LHG has attracted considerable attention, and mogrosides have been considered to be active ingredients against diabetes mellitus. We have found that these mogrosides could be metabolized into their secondary glycosides containing 1-3 glucose residues in type 2 diabetes mellitus (T2DM) rats in previous studies. These metabolites may be the antidiabetic components of LHG in vivo. Thus far, no reports have been found on reducing blood glucose of mogrosides containing 1-3 glucose residues.. The aim of this study was to confirm that mogrosides containing 1-3 glucose residues were the active components of LHG for antidiabetic effects and to understand their potential mechanisms of action.. First, the special fraction of mogrosides containing 1-3 glucose residues was separated from a 50% ethanol extract of LHG, and the chemical components were identified by ultra-performance liquid chromatography (UPLC) and named low-polar Siraitia grosvenorii glycosides (L-SGgly). Second, the antidiabetic effects of L-SGgly were evaluated by HFD/STZ-induced (high-fat diet and streptozocin) obese T2DM rats by indexing fasting blood glucose (FBG), fasting insulin (FINS), and insulin resistance, and then compared with other fractions in the separation process. The changes in serum lipid levels were also detected. Finally, possible mechanisms of antidiabetic activity of L-SGgly were identified as increasing GLP-1 levels and activating liver AMPK in T2DM rats.. The chemical analysis of L-SGgly showed that they contain 11-oxomogroside V, mogroside V, mogroside III, mogroside IIE, mogroside IIIA. L-SGgly, fractions separated from LHG extract, were verified to have obvious anti-hyperglycemic and anti-hyperlipidemic effects on T2DM rats. Furthermore, L-SGgly regulated insulin secretion in T2DM rats by increasing GLP-1 levels. These findings provide an explanation for the antidiabetic role of LHG.

Topics: Administration, Oral; Animals; Blood Glucose; Chemical Fractionation; Cucurbitaceae; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Drugs, Chinese Herbal; Glucagon-Like Peptide 1; Glycosides; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Insulin; Lipid Metabolism; Male; Obesity; Rats; Streptozocin; Triterpenes

Momordica charantia is a thermophilic voluble plant from the tropical and subtropical regions of Asia, Africa and the Caribbean. In central Europe, momordica requires greenhouse plantations. Mature fruits resemble a cucumber or a pumpkin and can be used as other similar vegetables. Crude fruits are very bitter and refreshing. For centuries the plant has been known in Chinese traditional medicine for its antidiabetic effects as well as for the treatment of cancer or infections caused by worms, viruses and malaria. Antidiabetic effects are attributed namely to cucurbitane type triterpenoids, charantin, p-insulin and 9cis-11trans-13trans-conjugated linolenic acid. These substances in momordica preparations show antidiabetic effectiveness in clinical studies by increasing insulin secretion and deceasing insulin resistance or glucose absorption from the gut. Beside this main effect the extract possesses certain neuroprotective and antioxidant effects (especially p9cis-11trans-13trans-conjugated linolenic acid) and contributes to normalize blood lipid and adipokine levels which results in the normalization of metabolic syndrome. Antidiabetic effectiveness of momordica was compared to active treatment with several oral antidiabetic drugs and proved comparable effects. However, the number of studies is limited and their methodological approach variable. Therefore, the evidence is so far inconclusive.

Topics: Diabetes Mellitus, Type 2; Glycosides; Humans; Momordica charantia; Phytotherapy; Plant Extracts; Triterpenes