柑橘精油成分分析及对灰葡萄孢菌的抑制作用

该研究采用水蒸气蒸馏法和有机试剂浸提法提取温州特早熟蜜橘橘皮精油,利用气相色谱-质谱联用(GC-MS)技术分析橘皮精油组成成分。以从福州周边果园收集草莓病果分离所得灰葡萄孢为研究对象,研究两种精油抑菌性能。结果显示：蒸馏油共鉴定出39种成分,醛类6种,烯萜类20种,醇类9种,酯类2种,酮类1种,有机酸1种;浸提法精油共鉴定出25种成分,烯萜类20种,醇类3种,烷烃类2种。柠檬烯为精油主要成分,水蒸气蒸馏法含量为82.37%,浸提法含量为85.25%。其次为γ-松油烯(7.78%,6.08%)、β-月桂烯(2.56%,2.06%)、α-蒎烯(1.35%,1.04%)。两种精油对灰葡萄孢最低抑菌体积分数分别为2.5%和5%。体外抑菌实验表明,精油能够通过对灰葡萄孢的菌丝、生长量、孢子萌发率、细胞透过性,诱导细胞死亡。草莓抑菌实验表明柑橘精油能够抑制灰葡萄孢在草莓果实上的生长,减缓果实的腐烂进程。其中,蒸馏油优于浸提油的抑菌效果。     

河源地区米粉原料中铝本底值的研究

目的分析河源地区5个产粮区的大米、市售常见品牌中6种玉米淀粉和河源2家城市自来水中铝元素的含量情况。方法对河源5个主要产粮区的共计200批次大米进行采样,对市售玉米淀粉随机抽取6个品牌共60批次样品,以及对河源两家饮用供水系统连续30 d取水样各30次,采用GB 5009.182-2017《食品安全国家标准食品中铝的测定》分别对大米、玉米淀粉和饮用水中铝元素进行测定。结果以欧盟确定的面制品中铝限量标准为参考,所抽的200批大米中,不合格样品有4批,总体不合格率为2.0%;所抽市售玉米淀粉铝60批,不合格样品有3批,总体不合格率为5.0%;东江河东源段供水系统中测定铝含量介于0.053～0.071 mg/L,平均含量为0.066 mg/L;新丰江供水系统中测定铝含量介于0.042～0.064 mg/L,平均含量为0.058 mg/L。估算出河源米粉原料带入的铝含量最高值为14.15 mg/kg。结论原料中铝检出情况证明河源米粉在不添加含铝添加剂的情况下也可能存在铝的残留,应引起相关部门的注意。同时建议尽快制定米粉制品中形态铝标准方法和米粉制品中铝元素限量标准。     

Antioxidant activity of ethanolic extract of Cortex fraxini and use in peanut oil

Cortex fraxini was extracted with 95% ethanol to obtain a crude antioxidant extract. The antioxidant activity was evaluated using the linoleic acid peroxidation method and the free radical scavenging assays, namely 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals. Cortex fraxini extract (CFE) showed high inhibition of peroxidation of linoleic acid when compared with butylated hydroxytoluene (BHT). CFE also exhibited excellent scavenging activity on DPPH and hydroxyl radicals. Total antioxidant activity was measured by the reduction of Mo(VI) to Mo(V) by the extract, and subsequent formation of a green phosphate/Mo(V) complex at acid pH. CFE had significant total antioxidant activity and the effects were increased with increasing reaction time. The total phenolic content of the sample, analyzed by using Folin–Ciocalteu’s reagent, was 91.33 mg/g dry weight expressed as pyrocatechol equivalents. Then the suitability of CFE as an antioxidant was determined in peanut oil, and the decrease of lipid oxidation was monitored using thiobarbituric acid-reactive substances (TBARS) assay. CFE treatment significantly (P < 0.05) reduced lipid oxidation in peanut oil compared to the control. No significant differences (P = 0.05) in lipid oxidation were detected between CFE antioxidant and BHT antioxidant samples.     

Effects of adlay bran and its ethanolic extract and residue on preneoplastic lesions of the colon in rats

BACKGROUND: Adlay (Coix lachryma‐jobi L. var. ma‐yuen Stapf) is a cereal crop used in traditional Chinese medicine and as a nutritious food. Epidemiologists have suspected that the low cancer rates in southeastern China might be related to adlay. Previous studies have shown that adlay has anti‐tumour and anti‐inflammatory activity. This study investigated the effect of adlay bran and its fractions on chemically induced colon carcinogenesis in rats. RESULTS: Adlay bran and its ethanolic extract and residue significantly reduced the number of preneoplastic aberrant crypt foci (ACF) and modified their mucin composition. The inhibitory effect of adlay bran ethanolic extract on ACF showed a dose dependence. Adlay bran and its ethanolic extract suppressed small ACF (one, two or three crypts) and ACF in the distal colon, while the residue suppressed large ACF (four or more crypts). CONCLUSION: These findings suggest the possibility that adlay bran and its ethanolic extract and residue inhibit colonic preneoplastic lesions in an early stage. Adlay and its fractions may have the potential to be developed as chemopreventive cereal products. Copyright © 2010 Society of Chemical Industry     

葛根提取物对高脂血症大鼠血脂及抗氧化能力的影响

目的:探讨葛根提取物对高脂血症大鼠血脂及抗氧化能力的影响。方法:将SD雄鼠随机分为正常对照组和高脂组,高脂组饲以高脂饲料建立高脂血症大鼠模型后,再随机分为高脂对照组和葛根提取物低、高剂量组,以50、100mg/kg·d-1剂量的葛根提取物分别对葛根提取物低、高剂量组灌胃4周,测定大鼠血清总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）,血清及肝脏超氧化物歧化酶（SOD）、丙二醛（MDA）。结果:葛根提取物各剂量组大鼠血清TC、TG、MDA和肝脏MDA水平、肝脏系数以及动脉粥样硬化指数（AI）均明显低于高脂对照组（p<0.05）,血清及肝脏SOD活性明显高于高脂对照组（p<0.05）。结论:葛根提取物对高脂血症大鼠有显著的降血脂和抗氧化作用,对防治动脉粥样硬化有益。      

The aqueous extract of Asparagus officinalis L. by-product exerts hypoglycaemic activity in streptozotocin-induced diabetic rats

BACKGROUND: The inedible bottom part of asparagus (Asparagus officinalis L.) spears, around one‐third to one‐half of the total length, is always discarded as by‐product. Since it still contains various bioactive substances, this by‐product might have potential usage in food supplements for its therapeutic effects. In this study the hypoglycaemic effect of the aqueous extract of asparagus by‐product (AEA) was evaluated in a streptozotocin (STZ)‐induced diabetic rat model. RESULTS: Continuous administration of AEA for 21 days significantly decreased fasting serum glucose and triglyceride levels but markedly increased body weight and hepatic glycogen level in diabetic rats. In an oral glucose tolerance test, both the blood glucose level measured at 30, 60 and 120 min after glucose loading and the area under the glucose curve showed a significant decrease after AEA treatment. CONCLUSION: The results of this study demonstrate that AEA has hypoglycaemic and hypotriglyceridaemic functions, suggesting that it might be useful in preventing diabetic complications associated with hyperglycaemia and hyperlipidaemia. Copyright © 2011 Society of Chemical Industry     

Hepatoprotective effect of the root extract of Decalepis hamiltonii against carbon tetrachloride-induced oxidative stress in rats

Decalepis hamiltonii, a climbing shrub, grows in the forests of peninsular India and is consumed for its health promoting properties. The hepatoprotective activity of the aqueous extract of the roots of D. hamiltonii with known antioxidant constituents was studied against carbon tetrachloride (CCl₄)-induced oxidative stress and liver injury in rats. Pretreatment of rats with aqueous extract of the roots of D. hamiltonii, single (50, 100 and 200 mg/kg b.w.) and multiple doses (50 and 100 mg/kg b.w. for 7 days) significantly prevented the CCl₄ (1 ml/kg b.w.) induced hepatic damage as indicated by the serum marker enzymes (AST, ALT, ALP, and LDH). Parallel to these changes, the root extract also prevented CCl₄-induced oxidative stress in the rat liver by inhibiting lipid peroxidation and protein carbonylation, and restoring the levels of antioxidant enzymes (SOD, CAT, GPx, GR, and GST) and glutathione. The biochemical changes were consistent with histopathological observations suggesting marked hepatoprotective effect of the root extract in a dose dependent manner. Protective effect of the aqueous extract of the roots of D. hamiltonii against CCl₄-induced acute hepatotoxicity could be attributed to the antioxidant constituents.     

富锶茶多糖提取物的抗氧化活性及其对H2O2诱导LO2细胞氧化损伤保护研究

目的 探明富锶茶多糖最佳提取工艺,并分析其体外抗氧化活性及对H2O2诱导LO2细胞氧化损伤的保护作用。方法 本研究采用热水超声辅助法从茶叶中提取富锶茶多糖,通过Box-Behnken响应面实验法对富锶茶多糖的提取工艺条件进行了优化;以1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)自由基、羟基自由基(·OH)、2,2’-联氮-二(3-乙基-苯并噻唑啉-6-磺酸)二铵盐[2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt, ABTS]阳离子自由基的清除能力和Fe3+的还原能力来为指标,分析富锶茶多糖的体外抗氧化活性;并以过氧化氢(H2O2)建立LO2细胞损伤模型,研究富锶茶多糖对LO2细胞氧化应激损伤的改善机制。结果 富锶茶多糖的最佳的提取工艺条件为：浸提时间57 min、料液比1:25 g/mL、提取温度67℃,富锶茶多糖得率为3.50%±0.12%。在体外抗氧化方面,富锶茶多糖对DPPH自由基、ABTS阳离子自由基、·OH和对Fe3+的还原能力具有较好的清除能力;在改善LO2细胞氧化应激损伤方面,随着多糖质量浓度升高,细胞存活率也显著提高,当多糖质量浓度为50 μg/mL时,细胞存活率达到99.5%;在清除机体过氧化机制上,相对于模型组,超氧化物歧化酶(superoxide dismutase, SOD)在低、中、高实验组中均有所增强,氧化氢酶(catalase, CAT)活力在中、高实验组中有显著提高,从细胞水平表明富锶茶多糖对LO2细胞氧化损伤具有明显的改善作用。结论 富锶茶多糖具有良好的抗氧化性以及对H2O2诱导LO2细胞氧化损伤有很好的保护作用,为富锶茶多糖功能性产品开发提供了理论基础。     

Short communication: Antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an “antiviral food.” At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5 mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28 mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.