Mogroside IIE,an in vivo metabolite of sweet agent,alleviates acute lung injury via Pla2g2a-EGFR inhibition

In the face of increasingly serious environmental pollution,the health of human lung tissues is also facing serious threats.Mogroside IIE(M2E)is the main metabolite of sweetening agents mogrosides from the anti-tussive Chinese herbal Siraitia grosvenori.The study elucidated the anti-inflammatory action and molecular mechanism of M2E against acute lung injury(ALI).A lipopolysaccharide(LPS)-induced ALI model was established in mice and MH-S cells were employed to explore the protective mechanism of M2E through the western blotting,co-immunoprecipitation,and quantitative real time-PCR analysis.The results indicated that M2E alleviated LPS-induced lung injury through restraining the activation of secreted phospholipase A2 type IIA(Pla2g2a)-epidermal growth factor receptor(EGFR).The interaction of Pla2g2a and EGFR was identified by co-immunoprecipitation.In addition,M2E protected ALI induced with LPS against inflammatory and damage which were significantly dependent upon the downregulation of AKT and m TOR via the inhibition of Pla2g2a-EGFR.Pla2g2a may represent a potential target for M2E in the improvement of LPS-induced lung injury,which may represent a promising strategy to treat ALI.

Assignments of ~1H and ^(13)C NMR Signals of Mogroside Ⅳa

Aim To investigate the structure of mogroside Ⅳa isolated from traditionalChinese medicine fructus mo-mordicae [fruits of Siraitia grosvenori (Swingle) C. Jeffery] andsummarize the NMR characteristics of the structure. Methods Common extraction, separation andpurification methods were used. Various NMR techniques including ~1H NMR, ^(13)C NMR, DEPT, ~1H-~1HCOSY, HSQC, HMBC, NOESY and molecular model simulated by computer were used to elucidate thestructure. Results ~1H and ^(13)C NMR signals of mogroside Ⅳa were assigned, and spectroscopicbasis was obtained for identification of such type of compounds. Conclusion 1D and 2D NMR techniquesincluding ~1H-~1H COSY, HSQC, HMBC, NOESY spectra are powerful tools for structure analysis. Thestructure determined by NMR methods is identical with energy minimized conformation simulated bycomputer.

Effects of Mogroside V on Glucose and Lipid Metabolism in High Fat Diet Mice

[Objectives]To explore the effects and mechanism of mogroside V(MV)on glucose and lipid metabolism in high-fat diet(HFD)mice.[Methods]The experiment fed mice with high-fat diet for 8 weeks,and 40 mice with successful modeling were randomly divided into normal group,model group,and MV dose group(100,200 mg/kg),with 10 mice in each group.From the ninth week,the MV dose group was given intragastric administration,and the normal group and the model group were given an equal volume of distilled water by intragastric administration for 6 weeks,then killed and blood samples and livers were collected.Serum triglycerides(TG),total cholesterol(TC),low density lipoprotein cholesterol(LDL-C),high density lipoprotein cholesterol(HDL-C),free fatty acids(FFA),Advanced glycation end products(AGE-P)-peptides(AGE-P)and glycosylated hemoglobin(HbA1c)content,and TG and hepatic glycogen content in liver were detected by biochemical method.Fasting blood glucose(FBG)was measured by glucose oxidase method.The fasting serum insulin(FINS)content was detected by enzyme-linked immunosorbent assay(ELISA),and the insulin resistance index(HOMA-IR)was calculated.Oil red O staining was used to observe the fat deposition in liver tissue.[Results]MV(100,200 mg/kg)dose groups could significantly down-regulate the contents of TC,TG,LDL-C,FBG,FINS,AGE-P and HbA1c and HOMA-IR,and up-regulate HDL-C and hepatic glycogen content and reduce the fat deposits.[Conclusions]The mechanism of MV regulating glucose and lipid metabolism in mice may be related to the regulation of insulin resistance.

Microwave Digestion Sample Hydride Generation-Atomic Fluorescence Spectrometry Determines Trace Selenium of Mogroside

0.2000g mogroside sample is digested by 7.0ml nitric acid and 3.0ml hydrogen peroxide, and generated by coprecipitation enrichment hydride - atomic fluorescence spectrometry determines trace selenium in it. Under optimum experiment conditions, a standard curve was produced using selenium standard solution, the linear equation is Ise=2890.6c＋0.0012,compared wish the linear relaticnship is not by coprecipitation direct determination of standard series Ise=82.56c＋0.0018 Selenium detection sensitivity was increased by 35.01 times,the correlation coefficient of obtained linear regression equation is 0.9996, the detection limit is 0.0012~tg/L and the relative standard deviation is 0.76% （n=5）. Containing 0.1808pg.g-1 Se Luo Han Shen samples. Based on mogroside sample, add a certain of standard solution to do recovery experiment, the obtained recovery rate is in 95.8%-103.6% and the result is satisfactory.

Potential Anticancer Effect of Bioactive Extract of Monk Fruit (Siraitia grosvenori) on Human Prostate and Bladder Cancer Cells

Prostate and bladder cancers are the two prevalent urological cancers, and several therapeutic options are currently available but the outcomes have not been satisfactory. To find the better therapeutic option, we investigated if the bioactive extracts of monk fruit, mogrosides, with potential anticancer activity might have anticancer effect against prostate and bladder cancer cells. Four of commercial products made of mogrosides known as Lakantoò (LKT) products, LK1, LK2, LLE, and MOG, were then tested. A dose-dependent study at given concentrations of four products showed that LK1 and LK2 had little effects, while LLE and MOG showed a significant cell viability reduction in both PC-3 and T24 cells. To explore the anticancer mechanism of such products, cell cycle analysis was first performed. Such analysis revealed that LLE and MOG, not LK1 and LK2, led to a G1 cell cycle arrest. Potential induction of endoplasmic reticulum (ER) stress was next examined because it is known to be linked to a cell cycle arrest. The three key regulators involved in ER stress were all up-regulated with LLE or MOG, indicating induction of ER stress. As ER stress is also known to induce apoptosis, this possibility was tested. The two apoptotic regulators were modulated in a specific manner with LLE or MOG, indicating induction of apoptosis. Lastly, to validate anticancer effect of LLE or MOG, anticancer effect of four chemotherapeutic drugs was also assessed in comparison with that of LLE/MOG. None of drugs had any effects but two products showed significant anticancer effect. In conclusion, two monk fruit products, LLE and MOG, demonstrated anticancer activity against PC-3 and T24 cells, significantly reducing cell viability and ultimately inducing apoptosis. Therefore, these two LKT products with few side effects may have clinical implications in the treatment of urological cancers.

罗汉果甜苷ⅡA的分离鉴定含量测定及其降糖抗氧化活性研究

为了研究罗汉果中甜苷成分的生物活性及资源含量,为其进一步开发利用提供实验依据,本文通过柱色谱技术,从罗汉果中分离出罗汉果甜苷ⅡA(mogrosideⅡA);利用核磁波谱(NMR),对mogrosideⅡA进行波谱数据归属;通过α-葡萄糖苷酶抑制活性和抗氧化活性测定,探讨罗汉果甜苷降血糖的可能机制;通过高效液相色谱串联质谱(high performance liquid chromatography-mass spectrometry,HPLC-MS)法,分析不同产地罗汉果中mogrosideⅡA的含量。通过研究,本文为mogrosideⅡA提供了完整的尚未见报道的波谱数据;同时,研究结果表明,mogrosideⅡA具有较强α-葡萄糖苷酶抑制活性,其IC 50为0.187±0.006 g/L,且呈现出剂量依赖的快速竞争性可逆抑制特点;另外,通过含量分析,发现产自永福县堡里镇的罗汉果中mogrosideⅡA的含量最高。

A structural and data-driven approach to engineering a plant cytochrome P450 enzyme

Functional manipulation of biosynthetic enzymes such as cytochrome P450 s(or P450 s) has attracted great interest in metabolic engineering of plant natural products.Cucurbitacins and mogrosides are plant triterpenoids that share the same backbone but display contrasting bioactivities.This structural and functional diversity of the two metabolites can be manipulated by engineering P450 s.However,the functional redesign of P450 s through directed evolution(DE) or structure-guided protein engineering is time consuming and challenging,often because of a lack of high-throughput screening methods and crystal structures of P450 s.In this study,we used an integrated approach combining computational protein design,evolutionary information,and experimental data-driven optimization to alter the substrate specificity of a multifunctional P450(CYP87 D20)from cucumber.After three rounds of iterative design and evaluation of 96 protein variants,CYP87 D20,which is involved in the cucurbitacin C biosynthetic pathway,was successfully transformed into a P450 mono-oxygenase that performs a single specific hydroxylation at C11 of cucurbitadienol.This integrated P450-engineering approach can be further applied to create a de novo pathway to produce mogrol,the precursor of the natural sweetener mogroside,or to alter the structural diversity of plant triterpenoids by functionally manipulating other P450 s.