Characteristics and upregulation of antioxidant enzymes of kitchen mint and oolong tea kombucha beverages

Kombucha is a healthy traditional beverage which is made by fermenting products with a symbiotic culture of acetic acid bacteria and yeasts. In present study, leaves of kitchen mint (Mentha cordifolia Opiz. Ex Fresen) and leaves of oolong tea (Camellia sinensis) were fermented in kombucha formula. After fermentation, titratable acidity contents and ethanol of kitchen mint, oolong tea, and mixtures of oolong tea and kitchen mint kombucha samples gradually increased with a period of fermentation time. At day 14 of fermentation, phenolic compounds and flavonoids were increased in all kombucha samples. The numbers of acetic acid bacteria and yeast in kombucha had gradually raised during 7–14 days of fermentation. DPPH and ABTS scavenging activities of these kombucha increased over a period of fermentation time and shown the highest antioxidant capacity on day 14 of fermentation. In addition, all kombucha samples exhibited the antioxidant effects by attenuating H₂O₂-induced ROS production, increasing mRNA expression of catalase, glutathione reductase (GRe), and Mn-SOD, and inducing GRe enzymatic activity in HEK-293 cells. Kombucha beverage can be used as the healthy beverages for attenuation of oxidative stress in many diseases.     

Improved Ethanol Production from Xylose by Candida shehatae Induced by Dielectric Barrier Discharge Air Plasma

Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae （C. shehatae） CICC1766 to atmospheric pressure dielectric barrier discharge （DBD） air plasma yields a clone （designated as C81015） with stability, which exhibits a higher ethanol fermentation rate from xylose, giving a maximal enhancement in ethanol production of 36.2% compared to the control （untreated）. However, the biomass production of C81015 is lower than that of the control. Analysis of the NADH （nicotinamide adenine dinucleotide）- and NADPH （nicotinamide adenine dinucleotide phosphate）- linked xylose reductases and NAD＋-linked xylitol dehydrogenase indicates that their activities are enhanced by 34.1%, 61.5% and 66.3%, respectively, suggesting that the activities of these three enzymes are responsible for improving ethanol fermentation in C81015 with xylose as a substrate. The results of this study show that DBD air plasma could serve as a novel and effective means of generating microbial strains that can better use xylose for ethanol fermentation.     

Bioefficacy of EPA–DHA from lipids recovered from fish processing wastes through biotechnological approaches

The effect of fish oil recovered from fish visceral waste (FVW-FO) on serum and liver lipids, activity of HMG-CoA reductase in liver microsomes and EPA + DHA incorporation in liver, heart and brain were evaluated. Rats were fed different concentrations of FVW-FO providing 1.25%, 2.50%, 5.0% EPA + DHA recovered by either fermentation or enzymatic hydrolysis for 8 weeks. Feeding FVW-FO reduce triacylglycerols (5.96–20.3%), total cholesterol (7.9–21.5%) and LDL (7.39–21.7%) cholesterol levels in serum compared to group fed on a control diet (groundnut oil). The activity of HMG-CoA reductase was reduced (p < 0.05) in the FVW-FO fed groups compared to the control. EPA + DHA level in serum, liver, brain and heart increased with increments in dietary EPA + DHA. Results show the hypolipidemic property of FVW-FO and reduced HMG-CoA reductase activity which is proportional to the incorporation of EPA + DHA. Recovery of FVW-FO will address the increasing demand for fish oil and reduce pollution problems.     

平卧菊三七对小鼠血糖及血脂的影响

高血糖和高血脂已严重威胁人类健康,本研究探讨平卧菊三七（GPM）对小鼠血糖和血脂的影响,并通过分子生物学手段阐明其作用机制。将40只昆明小鼠随机分成4组,即对照组、2%、4%和8% GPM,喂养小鼠12周,称量小鼠体重和脏器,测定血中的生化指标和肝脏及粪中脂类含量,用qRT-PCR及蛋白印迹等方法分析肝脏mRNA和蛋白表达的变化。结果显示GPM对小鼠体重增加和脏器重量没有明显变化。4%以上GPM与对照组相比显著降低血中的甘油三酯（TG）、总胆固醇、低密度脂蛋白的胆固醇和血糖及肝脏中TG的浓度。而粪中的TG却明显增加。8% GPM明显抑制羟甲基戊二酰CoA还原酶（HMGCR）的活力和mRNA及蛋白表达水平,而Glut4的mRNA和蛋白表达明显增加。以上结果表明GPM通过调节HMGCR和Glut4的mRNA及蛋白表达,和抑制肠道对TG吸收,达到降糖降脂作用。