乌龙茶多糖提取工艺及抗氧化作用研究

以乌龙茶为原料,研究不同因素对乌龙茶多糖得率的影响,初步探讨了乌龙茶多糖的抗氧化活性.结果表明,各因素对茶多糖得率的影响为:提取次数＞提取温度＞提取时间＞料液比;最佳提取工艺为提取时间80min,提取温度80℃,提取次数3次,料液比1∶35.在此条件下,茶多糖得率为15.73％.体外抗氧化试验表明,乌龙茶多糖对羟自由基、超氧阴离子自由基、1,1-苯基-2-苦基肼自由基均具有一定的清除效果,且清除率随浓度的增大而增加.     

Isolation and chemical characterisation of a polysaccharide from green tea (Camellia sinensis L.)

BACKGROUND: To contribute towards understanding the relationship of structure and bioactivity, a protein‐bound acidic polysaccharide named TPC3‐1 was isolated and purified from low‐grade green tea (Camellia sinensis L.). The homogeneity and weight average molecular weight of TPC3‐1 was determined by agarose gel electrophoresis and high‐performance gel permeation chromatography. The monosaccharide and amino acid composition of TPC3‐1 were analysed by gas chromatography and an amino acid analyser. The molecular structure of TPC3‐1 was characterised by Fourier transform infrared spectroscopy, ¹³C nuclear magnetic resonance spectroscopy and atomic force microscopy. RESULTS: Based on the data obtained, the average peak molecular weight of TPC3‐1 was about 120 kDa. TPC3‐1 was composed of L ‐arabinose, D ‐ribose, D ‐xylose, D ‐glucose and D ‐galactose with a molar ratio of 4.9:2.2:3.1:1.8:1.0. Fifteen amino acids were identified as components of the polymer. The TPC3‐1 molecule was found to have an anomeric carbon sign of both α and β configurations and high‐branched chains. The network structure of TPC3‐1 was observed. CONCLUSION: The tea polysaccharide TPC3‐1 was an acid protein‐bound polysaccharide with an image of network structure. The results presented here will facilitate further study of the relationship between the chemical structure and biological role of tea polysaccharide. Copyright © 2008 Society of Chemical Industry     

茶树花提取物及对茶叶籽油抗氧化作用的研究

采用乙醇为溶剂提取茶树花中的抗氧化物质,将提取液浓缩后的浓缩液加入到茶叶籽油中,通过真空干燥的方式使乙醇含量降至国标限量范围内,与直接以茶叶籽油浸提茶树花的添加方式及添加常用抗氧化剂的抗氧化效果进行比较,并以市售茶多酚代替茶树花进行对比实验。结果显示:茶树花提取物明显改善茶叶籽油的氧化稳定性,特别是以乙醇为载体的添加方式效果更为明显;茶树花提取物的抗氧化能力强于BHT、BHA,与脂溶性儿茶素的效果相当,弱于TBHQ。此外,以乙醇为载体的添加方式与直接浸提相比,前一种方式处理的茶叶籽油中儿茶素含量有所增加,黄酮含量也明显提高,此现象由市售茶多酚对比实验组所证实。     

一种薤白中性多糖的结构鉴定及体外抗氧化活性研究

采用分步醇沉和柱层析的方法,从薤白中分离纯化得到一种中性多糖AMP60N,其重均分子量为11200 u,由阿拉伯糖、葡萄糖和半乳糖构成,经红外光谱分析,同时结合高碘酸氧化、Smith降解及GC分析等手段,通过甲基化以及核磁共振波谱分析,初步确定了AMP60N主要由Glc(1→2)和Ara(1→5)构成,以Gal(1→6)和Glc(1→6)为支链的分子结构组成。对AMP60N清除各种自由基的研究表明其具有一定的体外抗氧化活性,呈现明显的量效关系,其抗氧化能力弱于V_C。      

茶树花水提多糖的精制工艺初探

目的:优化茶树花多糖(Tea Flower Polysaccharides,TFPS)的提取、脱色、脱蛋白工艺,精制TF-PS。方法:先以TFPS的提取率为指标,正交实验法对TFPS水提过程中的提取温度(A)、提取次数(B)、提取时间(C)及料水比(D)4因素进行优选研究;再分别对TFPS不同脱色、脱蛋白方法效果进行对比;最后UV检测和凝胶层析鉴定纯度。结果:影响TFPS提取率的主要因素是温度和时间;TFPS的最佳提取参数为:温度为95℃、料水比为1∶10、次数为3次、时间为3h;筛选得出树脂法脱色效果最好,酶法-Sevage联用法脱蛋白效果最好,最佳提取、脱色、脱蛋白工艺处理获得的TFPSⅠ,280nm处有紫外吸收峰,Sephadex G-150洗脱曲线为单一对称峰。结论:TFPS是糖蛋白复合体,TFPSⅠ具有高度均一性。     

低档绿茶多糖的酶法辅助提取及抗氧化活性研究

以皖西低档绿茶为原料,通过酶法辅助浸提茶多糖,然后对浸提液进行醇沉、真空干燥得粗多糖,比较三种不同方法对粗多糖脱蛋白效果,并研究茶多糖的体外抗氧化活性。结果表明:酶法辅助浸提的最优条件:料液比1∶30(g/m L)、酶解温度45℃、酶解时间120min、纤维素酶添加量12mg/g,果胶酶添加量12mg/g、浸提1次,茶多糖得率达到5.414%。三氯乙酸法、sevage法、木瓜蛋白酶法对粗多糖中蛋白的最大脱除率分别为84.14%、69.45%、74.34%,多糖损失率分别为18.56%、24.01%、12.34%。相对而言,木瓜蛋白酶法条件温和,更适合茶多糖脱蛋白。另外,茶多糖具有较强的还原能力以及对羟基自由基的清除能力,对亚硝基具有一定的清除作用。      

平阴玫瑰花托多糖的结构特征及抗氧化活性分析

为研究玫瑰花托多糖的结构特征和生物活性,采用DEAE-52纤维素阴离子交换柱层析将玫瑰花托多糖分离纯化为3个组分。结构分析表明玫瑰花托多糖的单糖组成为葡萄糖、阿拉伯糖、半乳糖、半乳糖醛酸、鼠李糖、葡萄糖醛酸、甘露糖(24.01:14.57:11.50:9.77:5.5:1.09:1),构型主要为呋喃糖。抗氧化实验表明,玫瑰花托多糖具有较强的抗氧化活性,其清除羟基自由基和DPPH自由基的EC₅₀值分别为699.46、514.31 mg/L。通过对比分析可知,玫瑰花托多糖的结构与玫瑰花瓣多糖的结构具有相似性,而玫瑰花托多糖的抗氧化活性稍强于玫瑰花瓣多糖。因此,玫瑰花托多糖是优良的天然抗氧化剂,有进一步开发利用的价值。     

金花茶多糖分离纯化、结构表征及其体外抗氧化性

采用水提醇沉法提取金花茶叶多糖,并采用DEAE-纤维素阴离子交换法对其进行分级纯化,获得TPS1、TPS2、TPS33个级分;通过凝胶色谱法、PMP柱前衍生高效液相色谱法、傅里叶红外光谱法对TPS1、TPS2、TPS3的分子量、单糖构成及微观结构进行分析,并研究其体外抗氧化性.结果表明:TPS1主要由葡萄糖、半乳糖、阿...     

白叶单枞黑茶抗氧化及体外降血糖活性研究

采用DPPH法、FRAP法和α-胰淀粉酶、α-葡萄糖苷酶抑制活性评价白叶单枞黑茶醇提物及其不同萃取物的抗氧化活性及体外降血糖活性。结果表明,乙酸乙酯萃取物中总黄酮及总酚含量最高,分别为（155.68±4.34）mg/g（以芦丁当量计）和（313.84±9.79）mg/g（以没食子当量计）;乙酸乙酯萃取物DPPH·清除活性的EC50为13.72μg/mL,FRAP铁离子还原能力EC1为43.38μg/mL;同时该萃取物也具有最强的体外降血糖活性,5mg/mL时对α-胰淀粉酶抑制率为95.83%,50μg/mL时对α-葡萄糖苷酶抑制率为91.30%。采用HPLC-DAD-MS/MS对乙酸乙酯萃取物进行分析,通过对紫外吸收光谱以及质谱信息进行分析,并参考相关文献,推定出12个化合物,这些化合物中包括茶生物碱以及多种以芹菜素、山奈酚为苷元的黄酮糖苷类成分。      

Physicochemical characterization and antioxidant activity of a polysaccharide isolated from oolong tea

Oolong tea polysaccharide (OTPS) is a kind of water-soluble polysaccharide isolated from oolong tea. Its molecular weight, composition, and structure were analyzed by laser light scattering analysis, chemical methods, gas chromatography, and atomic force microscopy (AFM). Antioxidant potential was detected by hydroxyl radical scavenging, inhibition of lipid peroxidation, DPPH radical scavenging, and reducing power assays. Results showed that OTPS was a non-reductive acid heteropolysaccharide bound to protein. The amounts of uronic acid, protein and neutral sugar in OTPS were 40.65, 19.59, and 26.66%, respectively. The neutral sugar was composed of d-rhamnose, l-arabinose, d-galactose, and d-glucose with a molar ratio of 1.37:1.89:1.00:1.30. The molecular weight of OTPS was 1.28 × 10⁶ Da and the second viral coefficient was 2.36 × 10⁻⁴ cm³ mol/g². A globular image of OTPS was imaged by AFM. OTPS showed effective antioxidant activities on hydroxyl radical scavenging assay and inhibition assay of lipid peroxidation.     

Chemical characteristics and antioxidant activities of polysaccharide purified from the seeds of Plantago asiatica L.

BACKGROUND: A water‐soluble polysaccharide from the seeds of Plantago asiatica L. (P. asiatica L. polysaccharide, PLP) was extracted with hot water and purified by gel filtration chromatography. The chemical characteristics of PLP were determined by high‐performance gel permeation chromatography (HPGPC) and Fourier transform infrared (FTIR) spectroscopy. In addition, the antioxidant activities of PLP in vitro were evaluated using various test systems, including scavenging of 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) radicals, scavenging of superoxide radicals generated by 1,2,3‐phentriol autoxidation, scavenging of hydroxyl radicals and inhibition of lipid peroxidation. RESULTS: The molecular weight of PLP was determined by HPGPC to be about 1894 kDa. PLP contained 29.2 g kg^?1 protein and 145.8 g kg^?1 uronic acid. The FTIR spectrum of PLP also revealed typical characteristics of a polysaccharide containing protein and uronic acid. Moreover, the results showed that PLP possessed antioxidant activities, but lower than those of ascorbic acid. CONCLUSION: PLP is an acid protein‐bound polysaccharide of high molecular weight, but its structure needs further study. The present results suggest that PLP could potentially be used as a natural antioxidant. Copyright © 2009 Society of Chemical Industry     

金瓜多糖不同分级组分的抗氧化和降血糖活性

目的:研究金瓜多糖不同分级组分的理化特性、结构、抗氧化性和降血糖活性。方法:采用水提醇沉法分级纯化得到4种金瓜多糖(CP-40、CP-60、CP-70、CP-80),通过高效液相色谱、傅里叶变换红外光谱等对其分子量、单糖组成、基团构成、抗氧化和降血糖活性进行研究。结果:金瓜多糖组分随着乙醇体积分数的增加,总糖含量升高,糖醛酸含量降低。4种多糖分子量不同,单糖组成相同但组成比例不同,且均具有多糖类物质的特征吸收峰。金瓜多糖体外抗氧化能力和降血糖活性存在明显的量—效关系,CP-70对DPPH自由基、羟自由基和超氧阴离子自由基清除作用高于其他组,抗氧化性最强,CP-80对α-葡萄糖苷酶和α-淀粉酶抑制作用最强,降血糖活性最佳。结论:金瓜多糖具有良好的抗氧化性和降血糖活性。     

Influence of the interactions between tea (Camellia sinensis) extracts and ascorbic acid on their antioxidant activity: analysis with interaction indexes and isobolograms

Products containing natural additives, including antioxidants, are usually perceived by consumers as safer than those with synthetic ones. Natural antioxidants, besides having a preservative activity, may exert beneficial health effects. Interactions between antioxidants may significantly change their antioxidant activity, thus in designing functional foods or food/cosmetic ingredients knowledge about the type of interactions could be useful. In the present study, the interactions between ascorbic acid (AA; vitamin C) and different black and green tea extracts and the influence on their antioxidant activities were investigated. The antioxidant activities of tea extracts and their mixtures with AA prepared in several different weight ratios were measured using the trolox equivalent antioxidant capacity (TEAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric-reducing antioxidant power (FRAP) methods. The type of interaction was determined by interaction indexes and isobolograms. It was found that the weight ratio of extracts to AA significantly influenced the antioxidant activity of a mixture and the type of interaction between these components. The weight ratio of tea extract to AA can cause the change of interaction, e.g. from antagonism to additivism or from additivism to synergism. The observed differences in the type of interactions were probably also a result of different extracts’ polyphenol composition and content. The type of interaction may also be affected by the medium in which extracts and AA interact, especially its pH and the solvent used. To obtain the best antioxidant effect, all these factors should be taken into account during the design of a tea extract–AA mixture.     

Antioxidant activities of different fractions of polysaccharide conjugates from green tea (Camellia Sinensis)

Three fractions of water-soluble polysaccharide conjugates, coded as TPC-1, TPC-2, and TPC-3, were isolated and purified from low-grade green tea (Camellia sinensis) by absorbent chromatography and ion exchange chromatography. Their chemical and physical characteristics were determined by chemical methods, gas chromatography and size exclusion chromatography with laser light scattering. Deoxyribose assay, photoreduction of Nitro Blue Tetrazolium (NBT) assay and lipid peroxidation inhibition assay were applied to test the antioxidant activities of tea polysaccharide conjugates in vitro. The results indicated that the three polysaccharide conjugates were heteropolysaccharides bounded with protein. TPC-1 was composed of l-arabinose (Ara), d-ribose (Rib), d-xylose (Xyl), d-glucose (Glc), d-galactose (Gal) and d-mannose (Man). TPC-2 was only composed of four monosaccharides: Ara, Rib, Glc and Man. There was no Man detected in TPC-3. The protein contents of TPC-1, TPC-2, and TPC-3 were 2.8%, 3.8% and 4.0% and the molecular weights were 26.8 × 10⁴, 11.8 × 10⁴, 4.2 × 10⁴, respectively. TPC-3 showed the highest antioxidant activities among the three fractions of polysaccharide conjugates, with an IC₅₀ of 182 μg/ml for the deoxyribose assay, and 93 μg/ml for the photoreduction of NBT assay, values which were lower than those of TPC-1 and TPC-2 (P < 0.01). The effects of the molecular weight and protein content of the polysaccharide conjugates on the improvement of the bioactivities appeared to be significant.     

昆仑雪菊茶总黄酮提取及抗氧化活性研究

以昆仑雪菊为原料,在单因素试验基础上,结合BoxBehnken响应面法,研究昆仑雪菊茶总黄酮的浸提工艺优化及抗氧化活性。结果表明:昆仑雪菊茶总黄酮的最佳浸提工艺条件为浸提时间13 min、浸提温度98℃、料液比178(g/mL),总黄酮得率为(20.39±0.07)%。最优条件下浸提物的DPPH·清除能力、铁还原力的IC_(50)分别为(82.40±1.98),(137.98±1.56)μg/mL,氧自由基吸收能力(ORAC值)为1 427.89μmol TE/g·DW,证明昆仑雪菊茶总黄酮具有很好的抗氧化活性。     

柠檬酸提取海带渣中多糖及其抗氧化活性与结构的研究

以海带渣为原料,采用柠檬酸提取法提取海带渣中多糖,并与直接柠檬酸提取的海带多糖进行抗氧化活性与结构比较。研究表明,海带渣多糖的提取率为7.00%±0.03%,其抗氧化活性与直接酸提的海带多糖相当,具有较好的氧自由基清除能力(ORAC值为130.13μmol Trolox/g)、DPPH自由基清除能力(18.89μmol Trolox/g)、ABTS自由基清除能力(53.58μmol Trolox/g)和还原力(37.56μmol Trolox/g),其中ORAC值比抗氧剂BHT高2倍。所得海带渣多糖的主要组分分子量为310182u(2.73%)和30515u(97.27%)。红外光谱图分析表明海带渣多糖与直接酸提的海带多糖结构相似。      

不同黑茶多糖的组成分析及其抗氧化活性

通过水提醇沉和Sevage法脱蛋白质获得茯砖茶、青砖茶、六堡茶、康砖茶、普洱茶和千两茶6种黑茶样品茶多糖,采用化学方法测定它们各自的中性糖、蛋白质、糖醛酸和多酚含量,并通过ABTS、DPPH、FRAP和总还原力等四种体系评价它们的抗氧化活性。结果表明,本次选用的6种黑茶样品茶多糖的组成与抗氧化活性有所差异,其中中性糖、蛋白质、糖醛酸和多酚四种成分含量范围分别为502.49~632.87,45.45~104.84,183.44~229.16,14.94~100.83 mg/g,且以普洱茶多糖的中性糖、蛋白质和多酚含量最高,而千两茶多糖的糖醛酸含量最高,此外它们均具有抗氧化能力,且在四种评价体系中从高到低的顺序相同,依次为普洱茶、康砖茶、六堡茶、青砖茶、茯砖茶和千两茶。本文为深入开展黑茶多糖组成与抗氧化活性研究及其功能产品开发提供了基础。      

苦瓜多糖的分子修饰及抗氧化活性研究

目的通过羧甲基化及金属络合对苦瓜多糖进行分子修饰,比较不同修饰方法对其抗氧化活性产生的影响。方法采用水提醇沉法分离制备苦瓜粗多糖(Momordica charantia polysaccharide,MCP),以DEAE-52离子交换层析梯度洗脱获得4种苦瓜多糖组分(MCPⅠ,MCPⅡ,MCPⅢ,MCPⅣ)。将其中活性较高组分MCPⅡ进行羧甲基化及金属络合获得苦瓜多糖衍生物CMMCPⅡ、MCPⅡ-Ca(Ⅱ),并以Fenton法检测其·OH清除率。结果苦瓜多糖活性组分MCPⅡ及其衍生物MCPⅡ-Ca(Ⅱ)、CMMCPⅡ均具有抗氧化活性,在质量浓度为0.7mg/m L时,其对·OH的清除率分别为58%、82%和93%,SC50值均在0.6 mg/m L以下,其中,苦瓜多糖羧甲基化衍生物的抗氧化活性最高。结论通过羧甲基化及金属络合可增强苦瓜多糖生物活性。