Gallic acid is the major component of grape seed extract that inhibits amyloid fibril formation

Many protein misfolding diseases, for example, Alzheimer’s, Parkinson’s and Huntington’s, are characterised by the accumulation of protein aggregates in an amyloid fibrillar form. Natural products which inhibit fibril formation are a promising avenue to explore as therapeutics for the treatment of these diseases. In this study we have shown, using in vitro thioflavin T assays and transmission electron microscopy, that grape seed extract inhibits fibril formation of kappa-casein (κ-CN), a milk protein which forms amyloid fibrils spontaneously under physiological conditions. Among the components of grape seed extract, gallic acid was the most active component at inhibiting κ-CN fibril formation, by stabilizing κ-CN to prevent its aggregation. Concomitantly, gallic acid significantly reduced the toxicity of κ-CN to pheochromocytoma12 cells. Furthermore, gallic acid effectively inhibited fibril formation by the amyloid-beta peptide, the putative causative agent in Alzheimer’s disease. It is concluded that the gallate moiety has the fibril-inhibitory activity.     

水果中阿斯巴甜的研究

采用高效液相色谱-三重四级杆串联质谱(HPLC-QQQ-MS/MS)对橙等8种水果中的苯丙氨酸、天冬氨酸和阿斯巴甜进行测定,采用气相顶空(HS-GC)对水果中的甲醇进行测定,并进行阿斯巴甜的模拟合成实验,研究在水果中是否存在阿斯巴甜及合成阿斯巴甜所必须的苯丙氨酸、天冬氨酸和甲醇以及它们之间的浓度关系。实验结果表明:8种水果中均含有阿斯巴甜、苯丙氨酸、天冬氨酸和甲醇。其中阿斯巴甜的含量为23.4～117μg/kg,天冬氨酸含量为8.72～186 mg/kg,苯丙氨酸含量为1.84～84.2 mg/kg,甲醇含量为1.81～248mg/kg。不同水果中阿斯巴甜含量差异不大,而苯丙氨酸、天冬氨酸和甲醇的含量差异较大。阿斯巴甜的含量与苯丙氨酸、天冬氨酸和甲醇的含量无明显相关性。     

番茄叶水提物急性毒性及其对急性炎症的影响

本文观察了番茄叶水提物对小鼠的急性毒性及其对脂多糖诱导急性炎症模型大鼠的影响。采用经典的急性毒性试验方法,观察小鼠口服给予番茄叶水提物的死亡率,按寇氏法计算半数致死量(LD50)。50只SD大鼠随机分为正常组、模型组、阳性药泼尼松5 mg/kg组与番茄叶水提物3.19、1.59 g/kg组,连续给药10 d,每天一次。以腹腔注射脂多糖(LPS)建立急性炎症模型,ELISA法测定血清白细胞介素1(IL-1)、白细胞介素6(IL-6)、肿瘤坏死因子(TNF-α)。结果显示,番茄叶水提物单次灌胃给药的LD50为46.44g/kg,95%可信限为39.52～54.60 g/kg。3.19 g/kg番茄叶水提物可明显降低LPS诱导的急性炎症小鼠血清IL-1、IL-6和TNF-α水平。番茄叶水提物抑制LPS诱导急性炎症的作用机制可能与其降低血清炎症因子水平有关。     

正交试验法优选复方四参颗粒剂的提取工艺

本文研究复方四参颗粒剂的提取工艺,采用正交试验法,以丹酚酸B提取率和干膏得率为指标,考察加水量、煎煮时间和煎煮次数对提取效果的影响,确立了复方四参颗粒剂的最佳提取工艺为:加8倍量水,提取2次,第一次时间为2 h,第二次为1 h。在最佳提取工艺条件下,干膏得率为16.58%,丹酚酸B的平均量为22.42mg。与正交试验的结果相符,说明该提取方法合理、稳定、可行。     

四种护脾养胃类中药水提物抗氧化能力测定

以罗丹明B为显色剂,采用分光光度法测定了护脾养胃类方剂中常见的当归、五味子、黄芩、红枣等四种中药水提物对·OH的清除能力.实验表明:这些中药永提取物对·OH都具有较强的清除作用,呈现明显的量效关系,其中红枣的清除能力最强.据此评价了这四种中药水提取物抗氧化能力大小顺序为:红枣＞当归＞黄芩＞五味子.     

Comparison of the Effects of Orally Administered Linoleic Acid,and Its Hydroperoxides and Secondary Autoxidation Products on Hepatic Lipid Metabolism in Rats

Linoleic acid, and its hydroperoxides and secondary autoxidation products were orally administered to rats (400 mg/rat). Their effects on hepatic lipid metabolism were examined. Linoleic acid reduced the activities of de novo synthesis of fatty acids and acetyl-CoA carboxylase. It decreased the CoASH level and caused the accumulation of long-chain acyl-CoA. Hydroperoxides changed the compositions of unsaturated fatty acids in the hepatic lipids and lowered the content of neutral lipids. Secondary products stimulated carnitine palmitoyltransferase and decreased the content of neutral lipids. They reduced the activities of de novo synthesis of fatty acids and acetyl-CoA carboxylase, and the levels of CoASH and acetyl-CoA. Thus, the effect of secondary products was apparently different from those of linoleic acid and its hydroperoxides.     

Studies on Chlorosis-Inducing Activities and Plant Growth Inhibition of Benzophenone Derivatives

Some benzophenones substituted with methyl, methoxy, hydroxy or halogen groups inhibited growth and induced chlorosis in various plants. The structure activity relationships about the chlorosis-inducing activity and the growth inhibitory activity of the 3-methyl-benzophenones were well expressed by use of hydrophobic contant π, and Hammett’s σ. The highest selectivity for phytotoxic activities against barnyardgrass and the rice plant was with 3,3′-dimethyl-4-methoxybenzophenone (Methoxyphenone).     

Flavor Components of Roasted Almond

Roasted almond volatiles were separated into basic, carbonyl and non-carbonyl fractions. Each fraction was analyzed by combination gas chromatography-mass spectrometry. Twenty-five compounds, in addition to eighteen known components, were identified. Many of the components identified were considered to contribute to the overall flavor. 2,5-Dimethyl-4- hydroxy-3(2H)-furanone, which was identified from methanol extract of roasted almond, seemed to make the largest contribution to the sweet aroma of roasted almond.     

In vitro anticancer activity of loquat tea by inducing apoptosis in human leukemia cells

Fresh loquat leaves have been used as folk health herb in Asian countries for long time, although the evidence supporting their functions is still minimal. This study aimed to clarify the chemopreventive effect of loquat tea extract (LTE) by investigating the inhibition on proliferation, and underlying mechanisms in human promyelocytic leukemia cells (HL-60). LTE inhibited proliferation of HL-60 in a dose-dependent manner. Molecular data showed that the isolated fraction of LTE induced apoptosis of HL-60 as characterized by DNA fragmentation; activation of caspase-3, -8, and -9; and inactivation of poly(ADP)ribose polymerase. Moreover, LTE fraction increased the ratio of pro-apoptotic Bcl-2-associated X protein (Bax)/anti-apoptotic myeloid cell leukemia 1 (Mcl-1) that caused mitochondrial membrane potential loss and cytochrome c released to cytosol. Thus, our data indicate that LTE might induce apoptosis in HL-60 cells through a mitochondrial dysfunction pathway. These findings enhance our understanding for chemopreventive function of loquat tea.     

Effects of Korean Red Ginseng extract on hepatic lipid accumulation in HepG2 cells

In this study, we investigated the effects of Korean red ginseng water extract (KRGE) on hepatic lipid accumulation in HepG2 cells. KRGE decreased hepatic triglyceride and cholesterol levels. Further, KRGE suppressed expression of fatty acid synthase (FAS) and 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase. These results suggest that KRGE may reduce hepatic lipid accumulation by inhibition of FAS and HMG-CoA reductase expression in HepG2 cells.