茶叶中吡咯里西啶生物碱检测技术、污染水平及健康风险研究进展

吡咯里西啶生物碱（pyrrolizidine alkaloids,PAs）是一类植物次级代谢产物,其中不饱和PAs及大部分PAs的氮氧化物具有多种毒性作用。PAs已被发现广泛存在于各类茶叶中,且成为导致我国茶叶出口受阻的主要污染物之一。本文综述了茶叶中PAs检测的前处理方法和色谱-质谱检测技术的发展,并展望其发展趋势;总结了不同国家茶叶PAs污染水平;分析了茶叶中PAs种类、不同茶叶的PAs差异以及茶叶与其他食品或农产品中PAs差异;解析了茶叶中PAs对人体的健康风险。我国茶叶PAs污染水平监测与风险评估研究相关数据处于缺失状态,急需开展茶叶中PAs污染来源与风险评估研究。     

植物中吡咯里西啶生物碱的检测分析方法研究进展

吡咯里西啶类生物碱（Pyrrolizidine alkaloids,PAs）是植物次生代谢产生的一类天然毒素,其中大部分不饱和型PAs及其氮氧化物（Pyrrolizidine alkaloid N-oxides,PANOs）具有多种毒性作用,并可通过膳食补充剂或食物链的形式进行传递从而威胁人类健康。PAs已被发现广泛存在于茶叶、蜂蜜等多种食品基质中,其污染成为令人担忧的食品安全问题。鉴于此,本文详尽梳理了不同国家不同食品基质中PAs的污染水平与可能的污染路径,综述了近年来PAs检测的前处理方法和分析检测技术的最新进展及发展趋势,分析了不同食品加工技术或烹饪制备对PAs污染物稳定性的影响,旨在为食品中PAs的检测研究、安全风险评估及控制提供警示和参考依据。

     

超高效液相色谱-高分辨质谱法同时测定茶叶中15种吡咯里西啶类生物碱

目的 建立超高效液相色谱-高分辨质谱法同时测定茶叶中15种吡咯里西啶类生物碱(PAs)的分析方法.方法 以甲醇甲酸水溶液作为提取溶剂,经超声提取,采用阳离子交换(MCX)固相萃取柱净化,以4.0 mmol/L甲酸铵溶液(含0.1％甲酸)和甲醇为流动相梯度洗脱,HSS T3柱(50 mm×2.1 mm,1.7 μm)分离...     

超高效液相色谱-串联质谱法测定铁皮石斛中的吡咯里西啶生物碱

为了测定铁皮石斛中的吡咯里西啶生物碱(pyrrolizidine alkaloids,PAs)的含量,该研究建立了固相萃取结合超高效液相色谱-串联质谱法同时测定铁皮石斛中16种不饱和PAs的分析方法.样品经0.05 mol/L硫酸甲醇提取、MCX固相萃取小柱纯化富集,以甲醇和0.005 mol/L甲酸铵-0.1％甲酸水...     

QuEChERS结合高效液相色谱-串联质谱法检测甘草中吡咯里西啶生物碱与风险分析

目的 建立QuEChERS和高效液相色谱-串联质谱法(high liquid chromatography-tandem mass spectrometry, HPLC-MS/MS)测定甘草中吡咯里西啶生物碱(pyrrolizidine alkaloids, PAs)。方法 甘草样品经0.05 mol/L硫酸水QuEChERS自动样品制备系统振荡提取后,用混合型阳离子交换固相萃取小柱(PCX SPE)进行净化,以5 mmol/L甲酸铵水(含0.1%甲酸) -5 mmol/L甲酸铵甲醇为流动相,Agilent Proshell 120 EC-C18柱进行分离,利用三重四极杆检测器在多反应监测模式下进行检测。结果 利用建立的前处理方法对甘草中34种PAs做添加回收实验,在10、20和50 μg/kg 3个浓度下的回收率为71.3%~112.0%,相对标准偏差为0.29%~8.18%,满足检测要求。利用建立的提取和检测方法对172个甘草样品中34种PAs进行监测,阳性样品检出率为22.1%,PAs总含量在9.5~118 μg/kg之间。其中石松胺、石松胺 N-氧化物、天芥菜碱和大尾摇碱N-氧化物的检出率最高。结论 本研究开发的甘草中PAs的提取和检测方法快速、准确,可同时测定甘草中34种PAs阳性。所有监测的甘草样品中PAs总量低于欧盟限量标准。     

液相色谱-三重四极杆质谱法测定花茶中5种吡咯里西啶类生物碱

目的 建立液相色谱-三重四极杆质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS) 同时测定花茶中5种吡咯里西啶类生物碱含量的分析方法。方法 将花茶样品均质粉碎后, 经0.1%甲酸水溶液浸泡, 涡旋, 超声提取, 高速离心后取上清液过固相萃取柱, 洗脱液氮吹吹干后用流动相复溶, 经ZORBAX Eclipse PLUS C18色谱柱(2.1 mm×100 mm, 1.8 μm)分离, 以0.1%甲酸溶液和乙腈为流动相进行梯度洗脱, 流速为0.30 mL/min, 柱温为30 ℃, 多反应监测模式测定, 外标法定量。结果 该方法线性关系良好, 相关系数为0.997~0.998; 方法的检出限(S/N=3)为3~5 μg/kg、定量限(S/N=10)为10~15 μg/kg; 在15、30、150 μg/kg添加水平下的平均回收率为89.69%~102.12%, 相对标准偏差为0.3%~5.4%。结论 该方法样品前处理简单快速、萃取效果好、灵敏度和选择性高, 适用于常规检测。     

茶叶中生物碱检测方法的研究进展

茶叶作为主要饮品之一, 对茶叶品质评定是必不可少的一个过程。茶叶的品质除了感官评定其色、香、味, 还可通过测定其茶多酚、氨基酸、矿物质、蛋白质、生物碱等活性成分的综合含量来评定。生物碱是茶叶中的主要活性成分之一, 不仅决定着茶叶的品质, 对人体也具有一定的有益作用。生物碱的快速、高效检测方法是茶叶品质评估和茶叶中生物碱提取及含量检测的前提和关键。本文参考了国内及国外对茶叶中生物碱研究方法的相关文献, 对茶叶生物碱(主要是咖啡碱、可可碱、茶叶碱)最主要的检测方法进行了综述。为进一步研究茶叶中生物碱及测定其含量, 评估茶叶的品质提供参考。     

燕麦生物碱研究进展

燕麦是全球的主要谷物之一,燕麦生物碱是燕麦中的主要功能成分,目前已发现20余种,其中主要为生物碱A、B、C。燕麦生物碱具有抗氧化、降血脂、消炎止痒和抑制细胞增殖等多种生理活性,燕麦生物碱的开发利用日益成为国内外学者的研究热点,但目前对燕麦生物碱的研究还不够系统和规范,对其种类、生理活性的探索还有待进一步发展。本文从燕麦生物碱的组成成分、提取方法、检测方法及生理活性等方面进行综述,主要介绍溶剂提取法、超临界CO_2流体萃取法和层析法等提取方法,高效液相色谱法和高效液相色谱-质谱联用法等检测方法,旨在为燕麦生物碱产品的深加工及开发利用提供科学依据。     

茶叶中啶虫脒残留基体标准样品的制备及测定

为了获得含啶虫脒残留的茶叶基体标准物质用于分析化学实验室质量体系控制,将啶虫脒以0.05 mg/kg茶叶用量对有机成茶喷施啶虫脒药液,阴干后,磨粉,混匀获得含啶虫脒残留的茶叶基体样品。用随机抽样法对其进行均匀性检验,用直线模型法对其进行稳定性检验,并通过多个实验室联合对其定值。结果表明该样品中啶虫脒含量无显著性差异,且在－10 ℃冷冻条件下储存180 d内未观察到明显的降解趋势。实验室联合测定,确定了该样品中啶虫脒的标准值为0.041 7 mg/kg,扩展不确定度（95%置信区间）为0.004 25 mg/kg。     

茶叶、茶鲜叶及茶汤中啶虫脒残留的检测

建立了茶叶、茶鲜叶、茶汤中的啶虫脒残留量的液相色谱检测方法。茶叶样品经乙腈提取,碱性NaCl饱和溶液萃取,Envi-Carb/NH2固相萃取柱净化,10 mL乙腈洗脱,液相色谱-紫外检测器检测,茶叶,茶鲜叶啶虫脒的添加浓度为0.1～1.0mg/kg时,其平均回收率为68.5%～103.6.0%,相对标准偏差(RSD)≤13.6%。茶汤啶虫脒的添加浓度为0.033～0.333 mg/L时,其平均回收率为:73%～103.8%,相对标准偏差(RSD)≤7.6%。用该方法最低检出浓度为分别为:0.07、0.09 mg/kg、0.002 mg/L,符合农药残留分析要求。该方法可用于茶叶中啶虫脒的常规检测和啶虫脒在茶叶生产中应用的安全性评价研究。     

Pyrrolizidine and tropane alkaloids in teas and the herbal teas peppermint,rooibos and chamomile in the Israeli market

Dehydro pyrrolizidine alkaloids (dehydro PAs) are carcinogenic phytotoxins prevalent in the Boraginaceae, Asteraceae and Fabaceae families. Dehydro PAs enter the food and feed chain by co-harvesting of crops intended for human and animal consumption as well as by carry-over into animal-based products such as milk, eggs and honey. Recently the occurrence of dehydro PAs in teas and herbal teas has gained increasing attention from the EU, due to the high levels of dehydro PAs found in commercially available teas and herbal teas in Germany and Switzerland. Furthermore, several tropane alkaloids (TAs, e.g. scopolamine and hyoscyamine) intoxications due to the consumption of contaminated herbal teas were reported in the literature. The aim of the present study was to determine the dehydro PAs and TAs levels in 70 pre-packed teabags of herbal and non-herbal tea types sold in supermarkets in Israel. Chamomile, peppermint and rooibos teas contained high dehydro PAs levels in almost all samples analysed. Lower amounts were detected in black and green teas, while no dehydro PAs were found in fennel and melissa herbal teas. Total dehydro PAs concentrations in chamomile, peppermint and rooibos teas ranged from 20 to 1729 μg/kg. Except for black tea containing only mono-ester retrorsine-type dehydro PAs, all other teas and herbal teas showed mixed patterns of dehydro PA ester types, indicating a contamination by various weed species during harvesting and/or production. The TA levels per teabag were below the recommended acute reference dose; however, the positive findings of TAs in all peppermint tea samples warrant a more extensive survey. The partially high levels of dehydro PAs found in teas and herbal teas present an urgent warning letter to the regulatory authorities to perform routine quality control analysis and implement maximum residual levels for dehydro PAs.     

Pyrrolizidine alkaloids in food and feed on the Belgian market

Pyrrolizidine alkaloids (PAs) are widely distributed plant toxins with species dependent hepatotoxic, carcinogenic, genotoxic and pneumotoxic risks. In a recent European Food Safety Authority (EFSA) opinion, only two data sets from one European country were received for honey, while one feed data set was included. No data are available for food or feed samples from the Belgian market. We developed an LC-MS/MS method, which allowed the detection and quantification of 16 PAs in a broad range of matrices in the sub ng g^?1 range. The method was validated in milk, honey and hay and applied to honey, tea (Camellia sinensis), scented tea, herbal tea, milk and feed samples bought on the Belgian market. The results confirmed that tea, scented tea, herbal tea and honey are important food sources of pyrrolizidine alkaloid contamination in Belgium. Furthermore, we detected PAs in 4 of 63 commercial milk samples. A high incidence rate of PAs in lucerne (alfalfa)-based horse feed and in rabbit feed was detected, while bird feed samples were less contaminated. We report for the first time the presence of monocrotaline, intermedine, lycopsamine, heliotrine and echimidine in cat food.     

Determination of pyrrolizidine alkaloids in tea,herbal drugs and honey

Honey was previously considered to be one of the main food sources of human pyrrolizidine alkaloid (PA) exposure in Europe. However, comprehensive analyses of honey and tea sampled in the Berlin retail market revealed unexpected high PA amounts in teas. This study comprised the analysis of 87 honey as well as 274 tea samples including black, green, rooibos, melissa, peppermint, chamomile, fennel, nettle, and mixed herbal tea or fruit tea. Total PA concentrations in tea ranged from < LOD to 5647 µg kg^?1, while a mean value of about 10 µg kg^?1 was found in honey samples. Additionally, herbal drugs were investigated to identify the source of PA in teas. Results suggest that PA in tea samples are most likely a contamination caused by co-harvesting of PA-producing plants. In some cases such as fennel, anise or caraway, it cannot be excluded that these plants are able to produce PA themselves.     

Pyrrolizidine alkaloids in food: downstream contamination in the food chain caused by honey and pollen

In recent years, there has been a steadily growing number of published data on pyrrolizidine alkaloids (PAs) in honey and pollen. This raises the question whether honey and/or pollen used as ingredients in food processing might provoke a downstream contamination in the food chain. Here we addressed two different facets in connection with PAs in honey and pollen. First, we analysed the PA content of several food types such as mead (n?=?19), candy (n?=?10), fennel honey (n?=?9), soft drinks (n?=?5), power bars and cereals (n?=?7), jelly babies (n?=?3), baby food (n?=?3), supplements (n?=?3) and fruit sauce (n?=?1) that contained honey as an ingredient in the range of 5% to approximately 37%. Eight out of 60 retail samples were tested as being PA-positive, corresponding to 13%. Positive samples were found in mead, candy and fennel honey, and the average PA content was calculated to be 0.10?µg?g^–1 retronecine equivalents (ranging from 0.010 to 0.484?µg?g^–1). Furthermore, we investigated the question whether and how PAs from PA pollen are transferred from pollen into honey. We conducted model experiments with floral pollen of Senecio vernalis and PA free honey and tested the influence of the quantity of PA pollen, contact time and a simulated honey filtration on the final PA content of honey. It could clearly be demonstrated that the PA content of honey was directly proportional to the amount of PA pollen in honey and that the transfer of PAs from pollen to honey was a rather quick process. Consequently, PA pollen represents a major source for the observed PA content in honey. On the other hand, a good portion remains in the pollen. This fraction is not detected by the common analytical methods, but will be ingested, and it represents an unknown amount of ‘hidden’ PAs. In addition, the results showed that a technically and legally possible honey filtration (including the removal of all pollen) would not be an option to reduce the PA level of the final product significantly.     

葡聚糖凝胶LH-20分离制备生物碱、无咖啡碱茶多酚和茶色素工艺研究

本研究建立了一种环保高效同时分离制备生物碱、无咖啡碱茶多酚和茶色素的葡聚糖凝胶LH-20柱层析方法。第一步使用蒸馏水分离茶色素和生物碱;第二步采用60%（v/v）乙醇溶液反向洗脱得到无咖啡碱茶多酚产品。经定量分析,生物碱得率3.14%,其中含93.87%咖啡碱和6.08%可可碱。茶多酚的得率为12.27%,纯度为98.13%,其中儿茶素含量高达90.28%,抗氧化活性最强的EGCG含量达61.17%,咖啡碱未检出。柱层析对生物碱和茶多酚的回收率分别为98.14%和86.36%。副产的茶色素主要含有一些多酚氧化物以及黄酮苷类混合物,可作为天然色素利用。      

Pyrrolizidine alkaloids in honey: risk analysis by gas chromatography-mass spectrometry

Recently, contamination of honey with pyrrolizidine alkaloids (PA) has been reported as potential health risk. Therefore, it was of interest to develop a reliable tool for selective and quantitative determination of PA in honey. Sample preparation of the novel method comprises strong cation exchange SPE (SCX-SPE), followed by two reduction steps using zinc and LiAlH(4), as well as subsequent silylation. During this procedure the separated PA are converted into the necin backbone, the common structural feature of PA toxicity, which is analyzed by GC-MS in the SIM mode. The procedure was validated using PA from extracts of Senecio vernalis as well as authentic PA standards including their corresponding N-oxides. The PA content of honey samples was quantified with heliotrine as internal standard. The method was applied to generate a dataset in order to evaluate the potential risk of PA contamination especially for retail honeys available on the German/European market. No selection criteria in terms of floral or geographical origin were applied on the samples before analysis. In total, 216 commercially available floral honey samples were analyzed. Among them 19 samples contained PA, in the range of 0.019-0.120 microg/g, calculated as retronecine equivalents. The reported method facilitates the selective determination of PA without the need to identify each individual PA independently. The PA contamination of honey is expressed in terms of a single sum parameter and no background information such as foraged plants and pollen analysis is necessary. The LOQ is 0.01 ppm with a S/N of 7:1.     

Total nitrogen and purine alkaloids in the tea plant throughout the year

Notable seasonal changes of the levels of purine alkaloids, caffeine and theobromine, in the stem and leaves of the new shoot of tea (Camellia sinensis (L) O. Kuntze cv. Yabukita) were observed, suggesting metabolism and/or translocation of the alkaloids. The alkaloids decreased significantly in August and in October and November while total nitrogen increased appreciably in November and December. The results indicate that the alkaloids have no role in the storage of nitrogen during the winter months.