Antimicrobial and antibiofilm activities of procyanidins extracted from laurel wood against a selection of foodborne microorganisms

This study aimed to evaluate the antimicrobial and antibiofilm activities of two procyanidins isolated from an ethyl acetate extract of laurel wood against a selection of foodborne pathogens. The analysis of the extract by HPLC–DAD/ESI–MS allowed us to detect the presence of two procyanidins, which were selectively isolated and identified by chromatographic and spectroscopic means as cinnamtannin B‐1 ( 1 ) and procyanidin B‐2 ( 2 ). Procyanidins 1 and 2 exhibited two biological activities: inhibition of bacterial growth at high concentrations and prevention of biofilm formation at lower concentrations. Synergistic effect was also detected when both compounds were tested in combination against Listeria monocytogenes. Significant effects were also detected on disruption of preformed biofilm. The ability of procyanidins to inhibit microbial growth and biofilm formation and to synergistically work with each other may stimulate a market as natural food preservatives, and/or natural sanitisers for processing equipment where foodborne pathogens reside.     

Impact of apple procyanidins on sensory perception in model cider (part 1): Polymerisation degree and concentration

The impact of the degree of polymerization and of the concentration of procyanidins in a model solution of French cider was investigated. Four purified fractions of procyanidins at three concentrations were added in a solution containing water, ethanol, fructose and malic acid. The four studied sensory characteristics (bitterness, astringency, sweetness and sourness) were modified according to the concentration of procyanidins. The degree of polymerization (DP) of procyanidins influenced only bitterness and astringency but this impact was not the same for all concentrations. Despite the fact that pH, fructose and malic acid concentrations were the same in all samples, the perception of sweetness and sourness were modified according to the concentration of procyanidins.     

Procyanidin effects on adipocyte-related pathologies

Procyanidins, a class of flavonoids, have clear and well-defined beneficial effects against several pathologies including cardiovascular heart disease. Now, studies in vivo are revealing the effects of procyanidins against obesity, where they prevent weight gain and adipose tissue mass increase, and against diabetes and insulin resistance, where they act as antihiperglycemic agents. Several mechanisms may be responsible for these effects. One of these, due to the key role of adipose tissue in the development of obesity and insulin resistance, is their effect on adipocytes. In this review we compile the studies that indicate a protective role for procyanidins in obesity and insulin resistance, focusing on their effects on the adipocyte, where procyanidins modify lipid synthesis, lipid degradation, glucose uptake, and adipose differentiation.     

山楂原花青素的抗氧化活性研究

研究了山楂果实中的原花青素在溶液体系和脂质体体系中的体外抗氧化活性。在所用的实验模型中,山楂原花青素表现出较强的清除自由基和抑制脂质过氧化的能力。对.OH,山楂原花青素和Vc的IC50分别约为0.053mg/mL和0.11mg/mL;对O2-.,山楂原花青素和VC的IC50分别约为0.05mg/mL和0.17mg/mL。在脂质体体系中,山楂原花青素抑制脂质过氧化的能力远大于VE。     

Proteins in white wine, I: Procyanidin occurrence in soluble proteins and insoluble protein hazes and its relationship to protein instability

The presence of procyanidins in wine protein fractions was established by a chemical assay and by pyrolysis DI-EI MS/MS of proteins. The chemical assay, involving acid-catalysed oxidative degradation of the procyanidins, gave cyanidin which was specifically quantified by HPLC. The assay was calibrated with purified grape seed tannin (GST); procyanidin was expressed in μg GST. Cyanidin yields were little altered by the presence of a large excess of protein. The limit of detection of the assay was 1 μg GST and the limit of quantification 3.5 μg GST. Both heat-induced and natural hazes isolated from various white wines were all shown to contain procyanidins, with a content ranging from < 0.02 to 4.9% (w/w). Although a crude soluble protein isolate from white wine contained a detectable amount of procyanidins, none were found in fractions separated chromatographically from this isolate. This observation, and the absence of procyanidins in resolubilised heat-induced haze, demonstrated that procyanidins are only weakly associated with both heat-induced hazes and soluble wine proteins. Nevertheless, procyanidins appear to be implicated in the formation of protein hazes in wine, because many soluble wine proteins that had been rendered free of procyanidins would precipitate to give haze in wine but not in model wine which was devoid of phenolic compounds.     

原花青素的生物活性研究

综述了近年来，植物中的提取物一原花青素在生物活性方面的研究：抗氧化、抗衰老作用；对心脏灌注损伤的保护作用；对肝脏细胞的保健作用；抗炎作用；抗肿瘤作用；抗诱变作用；DNA损伤的保护作用等，提示此类成分具有较高的生物活性及开发价值。     

陕北小粒黑豆皮原花青素提取工艺及抗氧化性研究

提取陕北小粒黑豆皮中原花青素,考察乙醇浓度、提取时间、提取温度和液料比对其提取得率的影响,利用Box-Behnken设计试验,建立提取过程的数学模型及二次多项式回归方程,预测出最优提取条件,并对提取的原花青素进行抗氧化性研究。结果表明,陕北小粒黑豆皮提取原花青素的优化工艺条件为提取时间4.2h、提取温度53℃、液料比22:1(mL/g)、乙醇浓度60%,在该条件下提取得率为5.380%;原花青素对DPPH自由基、羟基自由基和超氧阴离子均具有一定的清除效果,其IC50值分别为0.075,0.590,0.220mg/mL。     

大孔树脂吸附纯化葡萄籽原花青素的研究

采用大孔树脂对葡萄籽原花青素进行吸附纯化,以吸附率和解吸率及纯化效果为指标,比较了7种大孔树脂对原花青素的吸附解吸性能。研究了上样量、洗脱剂浓度、上样流速、洗脱剂用量对原花青素纯化效果的影响。结果表明,AB-8大孔树脂对葡萄籽中原花青素的吸附效果最好,树脂体积为20 mL,上样量为80 mL,上样流速为40 mL/h,用40%的乙醇洗脱,洗脱剂用量为100 mL,洗脱流速为80 mL/h时的纯化效果最好,该条件下原花青素洗脱率为94.37%,所得溶质纯度可达89.63%。     

蓝莓原花青素的提取与检测方法

花青素属于酚类化合物中的类黄酮类,花青素广泛存在于自然界中,多达三百多种。具有极强的抗氧化作用,可以抵御自由基对人体的损伤,具有延缓衰老、抗辐射的功效。在医药保健、化妆品、食品添加等方面被广泛应用。本文阐述了蓝莓原花青素的提取方法及测定技术。