【目的】玉米发酵生产燃料乙醇的副产物酒糟蛋白饲料(DDGS)常作为蛋白质替代饲料广泛用于动物生产中。随着DDGS产业链的扩大,其生产过程中所带来的抗生素的残留问题应该得到重视,但目前关于DDGS中抗生素的残留研究报道较少。对全国经营...【目的】玉米发酵生产燃料乙醇的副产物酒糟蛋白饲料(DDGS)常作为蛋白质替代饲料广泛用于动物生产中。随着DDGS产业链的扩大,其生产过程中所带来的抗生素的残留问题应该得到重视,但目前关于DDGS中抗生素的残留研究报道较少。对全国经营和使用环节的玉米DDGS进行抽样调查,对70种抗生素的残留含量进行分析测定,以了解目前中国饲料用DDGS中抗生素的残留情况。【方法】首先利用四级杆飞行时间质谱(quadrupole time-of-flight mass spectrometry,QTOF)建立了大环内酯类、氟喹诺酮类、磺胺类、喹恶啉类、β-内酰胺类、林可胺类、四环素类、酰胺醇类等共70种抗生素药物基于质量数、保留时间和特征碎片离子的数据库。在全国9个省、市、自治区抽取经营和使用环节的玉米DDGS样品74批次,筛查其中可能含有的抗生素药物。样品的前处理:取一定量的均质样品,加入乙腈和水的混合溶液进行提取,经涡旋、震荡、离心后,取上清液过NH2固相萃取柱,收集淋洗液N2气浓缩至一定体积,过0.22μm滤膜。样品的分析:首先利用QTOF建立的筛查列表对样品DDGS中可能残留的抗生素进行初步筛选,以确定残留抗生素的种类,而后采用液相色谱串联质谱法(liquid chromatography-tandem mass spectrometry,LC-MS/MS)对发现疑似含有抗生素残留的样品进行定量分析,以确定抗生素的残留量。【结果】欧盟指令2002/657/EC规定了在应用质谱仪对目标化合物进行确证时的准则。一个母离子为2分,一个子离子为2.5分。在本试验条件下所有抗生素的检测结果都能达到这个要求,符合对目标化合物的确证准则。经QTOF定性分析后,抽样的所有DDGS中有一批次样品中含有抗生素残留,种类为甲氧苄啶。样品母离子峰、二级特征离子碎片、出峰时间与标准品完全一致,样品和标准品所有提取碎片离子及离子丰度比一致。利用LC-MS/MS对残留抗生素进行定量分析后,确定其残留量为107.7 ng·g-1。甲氧苄啶在添加浓度为10—1 000ng·mL-1,平均添加回收率为75.2%—97.9%,线性相关系数大于0.99,日内标准偏差为2.8%—5%,日间标准偏差为8%—10%。【结论】利用QTOF建立DDGS中抗生素类药物的定性筛选方法可作为玉米DDGS中残留抗生素快速筛查方法。存在残留的甲氧苄啶抗生素,可能在玉米发酵生产DDGS前被添加,目的是抑制有害微生物的生长繁殖。抽样分析结果表明,目前中国玉米DDGS中抗生素残留的种类较少、残留量也较低,但DDGS中抗生素残留情况仍不容忽视,相关部门也未给出DDGS发酵过程中可使用的抗生素的种类范围、使用限量以及使用规范。此外,还应该研究直接采用QTOF进行定量分析的方法,以及研究包括维吉尼亚霉素在内的其他抗生素的QTOF分析方法。展开更多
The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant ...The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant belonging to the Acanthaceae family, and is traditionally used to treat diabetes in Malaysia. nHexane, n-hexane: ethyl acetate(1:1, v/v), ethyl acetate, ethyl acetate: methanol(1:1, v/v), and methanol fractions were obtained via partitioning of the 80% methanolic crude extract. The in vitro α-glucosidase inhibitory activity was analyzed using all the fractions collected, followed by profiling of the metabolites using liquid chromatography combined with mass spectrometry. The partial least square(PLS) statistical model was developed using the SIMCA P^+14.0 software and the following four inhibitors were obtained:(1) 4,6,8-Megastigmatrien-3-one;(2) N-Isobutyl-2-nonen-6,8-diynamide;(3) 1′,2′-bis(acetyloxy)-3′,4′-didehydro-2′-hydro-β, ψ-carotene; and(4) 22-acetate-3-hydroxy-21-(6-methyl-2,4-octadienoate)-olean-12-en-28-oic acid. The in silico study performed via molecular docking with the crystal structure of yeast isomaltase(PDB code: 3 A4 A) involved a hydrogen bond and some hydrophobic interactions between the inhibitors and protein. The residues that interacted include ASN259, HID295, LYS156, ARG335,and GLY209 with a hydrogen bond, while TRP15, TYR158, VAL232, HIE280, ALA292, PRO312, LEU313,VAL313, PHE314, ARG315, TYR316, VAL319, and TRP343 with other forms of bonding.展开更多
文摘【目的】玉米发酵生产燃料乙醇的副产物酒糟蛋白饲料(DDGS)常作为蛋白质替代饲料广泛用于动物生产中。随着DDGS产业链的扩大,其生产过程中所带来的抗生素的残留问题应该得到重视,但目前关于DDGS中抗生素的残留研究报道较少。对全国经营和使用环节的玉米DDGS进行抽样调查,对70种抗生素的残留含量进行分析测定,以了解目前中国饲料用DDGS中抗生素的残留情况。【方法】首先利用四级杆飞行时间质谱(quadrupole time-of-flight mass spectrometry,QTOF)建立了大环内酯类、氟喹诺酮类、磺胺类、喹恶啉类、β-内酰胺类、林可胺类、四环素类、酰胺醇类等共70种抗生素药物基于质量数、保留时间和特征碎片离子的数据库。在全国9个省、市、自治区抽取经营和使用环节的玉米DDGS样品74批次,筛查其中可能含有的抗生素药物。样品的前处理:取一定量的均质样品,加入乙腈和水的混合溶液进行提取,经涡旋、震荡、离心后,取上清液过NH2固相萃取柱,收集淋洗液N2气浓缩至一定体积,过0.22μm滤膜。样品的分析:首先利用QTOF建立的筛查列表对样品DDGS中可能残留的抗生素进行初步筛选,以确定残留抗生素的种类,而后采用液相色谱串联质谱法(liquid chromatography-tandem mass spectrometry,LC-MS/MS)对发现疑似含有抗生素残留的样品进行定量分析,以确定抗生素的残留量。【结果】欧盟指令2002/657/EC规定了在应用质谱仪对目标化合物进行确证时的准则。一个母离子为2分,一个子离子为2.5分。在本试验条件下所有抗生素的检测结果都能达到这个要求,符合对目标化合物的确证准则。经QTOF定性分析后,抽样的所有DDGS中有一批次样品中含有抗生素残留,种类为甲氧苄啶。样品母离子峰、二级特征离子碎片、出峰时间与标准品完全一致,样品和标准品所有提取碎片离子及离子丰度比一致。利用LC-MS/MS对残留抗生素进行定量分析后,确定其残留量为107.7 ng·g-1。甲氧苄啶在添加浓度为10—1 000ng·mL-1,平均添加回收率为75.2%—97.9%,线性相关系数大于0.99,日内标准偏差为2.8%—5%,日间标准偏差为8%—10%。【结论】利用QTOF建立DDGS中抗生素类药物的定性筛选方法可作为玉米DDGS中残留抗生素快速筛查方法。存在残留的甲氧苄啶抗生素,可能在玉米发酵生产DDGS前被添加,目的是抑制有害微生物的生长繁殖。抽样分析结果表明,目前中国玉米DDGS中抗生素残留的种类较少、残留量也较低,但DDGS中抗生素残留情况仍不容忽视,相关部门也未给出DDGS发酵过程中可使用的抗生素的种类范围、使用限量以及使用规范。此外,还应该研究直接采用QTOF进行定量分析的方法,以及研究包括维吉尼亚霉素在内的其他抗生素的QTOF分析方法。
基金the Ministry of Agriculture of Malaysia for NKEA Research Grant Scheme fund (NRGS SP15-0600182)International Islamic University Malaysia for Publication Research Initiative Grant fund (PRIGS18-027-0027)
文摘The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant belonging to the Acanthaceae family, and is traditionally used to treat diabetes in Malaysia. nHexane, n-hexane: ethyl acetate(1:1, v/v), ethyl acetate, ethyl acetate: methanol(1:1, v/v), and methanol fractions were obtained via partitioning of the 80% methanolic crude extract. The in vitro α-glucosidase inhibitory activity was analyzed using all the fractions collected, followed by profiling of the metabolites using liquid chromatography combined with mass spectrometry. The partial least square(PLS) statistical model was developed using the SIMCA P^+14.0 software and the following four inhibitors were obtained:(1) 4,6,8-Megastigmatrien-3-one;(2) N-Isobutyl-2-nonen-6,8-diynamide;(3) 1′,2′-bis(acetyloxy)-3′,4′-didehydro-2′-hydro-β, ψ-carotene; and(4) 22-acetate-3-hydroxy-21-(6-methyl-2,4-octadienoate)-olean-12-en-28-oic acid. The in silico study performed via molecular docking with the crystal structure of yeast isomaltase(PDB code: 3 A4 A) involved a hydrogen bond and some hydrophobic interactions between the inhibitors and protein. The residues that interacted include ASN259, HID295, LYS156, ARG335,and GLY209 with a hydrogen bond, while TRP15, TYR158, VAL232, HIE280, ALA292, PRO312, LEU313,VAL313, PHE314, ARG315, TYR316, VAL319, and TRP343 with other forms of bonding.
