Phenolic composition and radical scavenging activity of commercial Greek white wines from Vitis vinifera L. cv. Malagousia

Seven commercial white wine samples of the Malagousia cultivar were investigated for the first time with regard to their phenolic composition and radical scavenging activity. Total phenol content, corrected for ascorbic acid contribution (0–47 mg gallic acid equivalents/L of wine), ranged between 241 and 336 mg gallic acid equivalents/L of wine. On the other hand, the range for total hydroxycinnamates was 51.5–122.4 mg chlorogenic acid equivalents/L of wine and that for total flavanols 19.6–68.8 mg catechin equivalents/L wine. Fifteen phenolic compounds were identified and quantified by gas chromatography/mass spectrometry in the selective ion monitoring and high-performance liquid chromatography coupled with diode array detector. Tyrosol, caftaric, caffeic and 2-S-glutathionyl caffeoyl tartaric (GRP) acids were the major phenolics in all samples with mean concentrations of 12.32, 10.71, 10.17 and 4.79 mg/L wine, respectively. Catechin (3.75 mg/L) and p-coumaric acid (3.04 mg/L) followed in abundance. Variations in the values of GRP/caftaric (0.1–4.6) and caffeic/caftaric (0.4–4.2) acid concentrations, suggested differences in the degree of oxidation on one hand and hydrolytic processes during production and bottling on the other. Despite these variations, the radical scavenging activity of samples examined with DPPH and ABTS⁺ assays (mean value 0.85 and 3.45 mmol Trolox equivalents/L of wine) indicated a high efficiency in comparison to literature data on native and foreign white wines. The present findings can be useful for both technological and nutritional purposes.     

Uncovering the influence of antioxidants on polyphenol oxidation in wines using an electrochemical method: Cyclic voltammetry

The influence of sulfur dioxide, glutathione and ascorbic acid on the cyclic voltammograms of four representative wine polyphenols (catechin, caffeic acid, rutin and quercetin) and five different wines was investigated using a glassy carbon electrode in a model wine solution. Sulfur dioxide increased the anodic current and decreased the cathodic current for all four polyphenols and all wines, pointing to a rapid interaction of SO₂ with the oxidized polyphenol quinones. A similar trend was seen for glutathione, except that in the case of quercetin, addition of glutathione led to the formation of a second set of voltammetric peaks, corresponding to redox activity of a glutathione derivative. However, ascorbic acid produced no additional effect on the cyclic voltammograms of wine polyphenols and wines, beyond that expected for a simple sum of the polyphenol and ascorbic acid responses, with the exception that adsorption of quercetin and rutin on the carbon electrode caused a shift in the ascorbic acid oxidation peak to more positive potentials.     

The influence of beverage composition on delivery of phenolic compounds from coffee and tea

Epidemiological data suggest that consumption of coffee and tea is associated with a reduced risk of several chronic and degenerative diseases including cardiovascular disorders, diabetes, obesity and neurodegenerative disorders. Both coffee and tea are a rich source of phenolic compounds including chlorogenic acids in coffee; and flavan-3-ols as well as complex theaflavins and thearubigens in tea. Coffee and tea are two of the most commonly consumed beverages in the world and thus represent a significant opportunity to positively affect disease risk and outcomes globally. Central to this opportunity is a need to better understand factors that may affect the bioavailability of specific phenolic components from coffee and tea based beverages. An overview of the phenolic composition of coffee and tea is discussed in the context of how processing and composition might influence phenolic profiles and bioavailability of individual phenolic components. Specifically, the impact of beverage formulation, the extent and type of processing and the influence of digestion on stability, bioavailability and metabolism of bioactive phenolics from tea and coffee are discussed. The impact of co-formulation with ascorbic acid and other phytochemicals are discussed as strategies to improve absorption of these health promoting phytochemicals. A better understanding of how the beverage composition impacts phenolic profiles and their bioavailability is critical to development of beverage products designed to deliver specific health benefits.     

Effect of selenium enrichment on antioxidant activities and chemical composition of Lentinula edodes (Berk.) Pegl. mycelial extracts

Preparations derived from Lentinula edodes (Berk.) Pegl. mycelium are worldwide used as dietary supplements containing compounds active as immune system enhancers, demonstrating chemopreventive and anticancer activity. L. edodes mycelium enriched with organic forms of selenium like selenized yeast possess putative, higher cancer preventive properties. The objective of this study was to test the effect of enrichment in selenium on antioxidant, reducing and free radical scavenging activity of water and alcohol extracts from mycelium of L. edodes (Berk.). To elucidate the cause of enhanced antioxidant activity of extracts, a preliminary selenium speciation by specific oxido-reduction reaction was performed. Se-enrichment enhanced antioxidant activity, reducing power and free radical scavenging effect of mycelial extracts by almost 100–400%. Increase of activity was particularly high for diluted extracts (concentrations 0.1–0.5 mg/ml). The chemical composition of extracts from both Se-enriched and non-enriched mycelium was compared by determination of polyphenols, proteins, carbohydrates and lipids. Results showed that Se-enrichment enhanced antioxidant activities of mycelial extracts, likely by high amounts of organic Se-compounds (–II oxidation state) and elemental red selenium, and by increased polyphenols content. Our results suggest that Se-enrichment is a good method for enhancement of important activities of human dietary supplements, including Shiitake preparations.     

Antioxidant and anticancer activities of Chenopodium quinoa leaves extracts – In vitro study

The nutraceutical potential of Chenopodium quinoa Leaves (ChL) was assessed through analyses of their phenolic content, elucidation of the effect of ChL phenolic compounds on cancer cell properties and estimation of their antioxidative activity, bioaccessibility and bioavailability in vitro. Considerable amounts of ferulic, sinapinic and gallic acids, kaempferol, isorhamnetin and rutin were observed in the chemical ChL extract and were linked with its inhibitory effect on prostate cancer cell proliferation, motility and cellular competence for gap junctional communication. Both extracts, chemical and obtained after simulated digestion, exerted an inhibitory effect on lipoxygenase activity, paralleled by their considerable chelating, antioxidative, antiradical and reducing power. These observations indicate that phenolic ChL compounds may exert a chemopreventive and anticarcinogenic effect on oxidative stress and ROS-dependent intracellular signaling via synergic effects. The relatively high potential bioaccessibility and bioavailability of the compounds probably responsible for these effects demonstrates the suitability of ChL for dietary supplementation.     

Profile of phenolic compounds in Indonesian rice (Oryza sativa) varieties throughout post-harvest practices

Apart from being a foremost source of calories for a large part of the world’s population, cultivated rice (Oryza sativa) provides beneficial effects for human health through several bioactive compounds, including phenolics. Therefore, to earn this advantage, it is essential to retain the phenolics through appropriate post-harvest practices. In this paper, the profile of 10 individual phenolic compounds contained by rice grains after drying, dehusking and polishing processes were studied. A number of Indonesian rice cultivars from indica and javanica subspecies were acquired from conventional (IR-64, Umbul-umbul and Pandanwangi) and organic farming (Batang Lembang, Pandanwangi, black- and red-pigmented rice) were studied. Additionally, the effect of polishing degree on individual phenolics content in the grain was also evaluated. The level of phenolics decreased, also their relative values dramatically changed throughout a series of post-harvest processes. Moreover, changes on the composition of phenolic acids and its aldehydes in the grain have been described. p-Coumaric acid reflects the greatest differences on the phenolic composition during the course of post-harvest practices that altered from 48% to 8% portion to the total phenolics in paddies and polished grains, respectively. However, phenolics content in black-pigmented rice appeared to be the most persistent in the rice matrix. Since the profile of individual phenolics has also been evaluated on different polishing degrees (70%, 80%, 90% and 100% bran removal), the distribution of these compounds in the whole grain rice was effectively disclosed. These variations in the compositions and quantities of phenolics revealed the effect of post-harvest practices, varietal differences as their distribution in the grain.     

维药异常黑胆质成熟剂总酚对宫颈癌细胞体外生长的影响

目的:探讨维药异常黑胆质成熟剂总酚治疗人宫颈癌的可行性。方法:分别用不同浓度的异常黑胆质成熟剂总酚作用于人宫颈癌Hela细胞及SiHa细胞,于作用后24、48、72、96 h,用倒置显微镜观察细胞形态学变化,MTT比色法测定各组细胞的抑制率和半数抑制浓度(IC50)。结果:在25～125μg/mL浓度区间,总酚对Hela细胞的增殖有明显的抑制作用;在75～175μg/mL浓度区间,总酚对SiHa细胞的增殖有明显的抑制作用,且对2种细胞的抑制作用都呈明显的量效关系和时效关系(P<0.01);总酚作用于Hela细胞后48 h的IC50=(125.26±16.15)μg/mL,而作用于SiHa细胞后48 h的IC50=(134.51±2.55)μg/mL。两者比较差异无统计学意义(P>0.05);两种细胞经总酚作用后均出现明显的凋亡特征,且随着药物浓度增高及作用时间延长细胞形态学变化更明显。结论:异常黑胆质成熟剂总酚能抑制宫颈癌Hela细胞及SiHa细胞体外生长,且对两种宫颈癌细胞的抑制作用基本相同。故异常黑胆质成熟剂总酚可作为临床治疗宫颈癌的药物进一步深入研究。     

黄腊果根的化学成分研究

目的 研究黄腊果Stauntonia brachyanthera根的化学成分.方法 利用各种色谱学方法,对药材提取物进行分离纯化,采用核磁共振技术鉴定结构.结果 从黄蜡果根70％乙醇提取物中分离得到13个化合物,分别为3-甲氧基-4-羟基-桂皮醛(Ⅰ)、tortoside F(Ⅱ)、酪醇1-O-β-木糖基-(1→6)-O-β-葡萄糖苷(Ⅲ)、香草酸(Ⅳ)、丁香酸(Ⅴ)、saccharumoside B(Ⅵ)、甘草查儿酮A(Ⅶ)、芦丁(Ⅷ)、异槲皮苷(Ⅸ)、木犀草素-7-O-葡糖糖苷(Ⅹ)、荭草苷(Ⅺ)、6”-O-(3'-羟基-3'-甲基戊二酰)牡荆素(Ⅻ)、槲皮素(Ⅻ).结论 化合物Ⅰ、Ⅲ～Ⅵ、Ⅸ、Ⅺ～)ⅩⅢ均为首次从野木瓜属植物中分离得到.     

水芹总酚酸对小鼠CCl4肝损伤的保护作用

目的观察水芹总酚酸（OJTPA）对四氯化碳（CCl4）致小鼠急性肝损伤的保护作用。方法将180只小鼠随机分为正常组,联苯双酯阳性药物组,CCl4模型对照组和OJTPA高、中、低（500、250、125mg·kg^-1）3个剂量组。应用0．1％CCl4腹腔注射致小鼠急性肝损伤模型,通过测定小鼠血清中谷丙转氨酶（ALT）、谷草转氨酶（AST）活性以及小鼠肝组织中丙二醛（MDA）含量和超氧化物歧化酶（SOD）活力,并观察肝脏组织病理学变化,对OJTPA的保肝作用进行研究。结果模型组小鼠肝功能明显异常,肝组织变性、坏死严重;OJTPA组能明显改善CCl4中毒小鼠肝功能,其降酶率（ALT）以高、中、低剂量分别为74．74％、55．87％、7．25％;肝组织切片镜检证实,OJTPA能减轻中毒小鼠肝细胞损伤程度。结论OJTPA对急性肝损伤小鼠有较好的保肝作用。