棉籽油中游离棉酚降解产物化学标志物毒性、化学结构及污染现状研究

Xinjiang is China's largest main cotton producing areas, is also important cottonseed oil processing base, there are many oil extraction enterprises. Detoxification of gossypol in cottonseed is very difficult to monitor due to the situation of coexist of Modern oil extraction enterprises and township oil small workshops. So free gossypol in cottonseed oil has become an important factor affecting the quality of cottonseed oil. Although the testing standards of free gossypol have been developed in China, but the free gossypol in cottonseed oil is very unstable, significant degradation occurs has been confirmed in our preliminary studies, so it is difficult that to reflect the true quality by detecting the free gossypol, and what is more cottonseed oil degradation products could become a potential safety hazard. Therefore, it is very necessary to study the degradation products of free gossypol and evaluate secondary pollution of free gossypol. We will isolated, purified degradation products of free gossypol in cottonseed oil and structural characterization;Using NMR metabolomics method combined with cell toxicity，biochemical index, histological to evaluate the toxicity of the degradation products, and to establish detection method. Finally, through chemical markers content census of cottonseed oil samples for the Xinjiang market, this subject is to provide a scientific evaluation for Xinjiang free gossypol in cottonseed oil pollution and to lay the foundation for establishment of testing standards of the chemical markers of degradation products of cottonseed oil free gossypol.

新疆是我国最大的棉花产区，也是重要的棉籽油加工基地，榨油企业众多，由于现代化的榨油企业与乡镇榨油小作坊同时并存，棉籽油中棉酚脱毒情况监控难度大，游离棉酚成为影响新疆棉籽油品质的重要因素。目前我国虽然制定了棉籽油中游离棉酚的检测标准，但是我们的前期研究确认了游离棉酚在棉籽油中极不稳定，会发生明显的降解，游离棉酚含量检测很难反映棉酚脱毒情况；同时降解产物有可能成为棉籽油潜在的安全隐患。因此研究游离棉酚的降解产物，评价游离棉酚的二次污染情况非常必要。本课题将分离、纯化棉籽油中棉酚降解产物，表征结构；采用NMR代谢组学技术结合细胞毒性、生化指标、组织切片评价降解产物的毒性；确定能反映毒性的降解产物作为化学标志物，并建立其检测方法；最后通过对新疆市场上的棉籽油样品进行化学标志物含量普查，为新疆地区棉籽油中游离棉酚的污染提供科学的评价方法，为棉籽油中游离棉酚降解产物化学标志物检测标准的建立奠定基础。

新疆是我国最大的棉花产区，也是重要的棉籽油加工基地，但棉籽油中棉酚脱毒情况监控难度大，游离棉酚成为影响新疆棉籽油品质的重要因素。目前我国虽然制定了棉籽油中游离棉酚的检测标准，但是前期研究确认了游离棉酚在棉籽油中极不稳定，会发生明显的降解，游离棉酚含量检测很难反映棉酚脱毒情况，同时降解产物有可能成为棉籽油潜在的安全隐患。对此本课题首先采用HPLC法测定不同放置时间的棉籽油样品，建立游离棉酚与降解产物之间的线性关系；进而开展游离棉酚主要降解产物的分离、纯化、制备，利用液相色谱-傅立叶变换离子回旋共振质谱仪测定主要游离棉酚降解产物的准确分子量、推测分子式并鉴定其结构；利用体外细胞毒性实验和体内小鼠精子畸形实验考察主要游离棉酚降解产物毒性作用，结果表明棉酚降解产物的半数抑制率IC50为6.554 μg/mL，并且在实验剂量下，主要游离棉酚降解产物对小鼠精子具有致突变作用，证实四甲氧基棉酚具有生殖毒性；开展SD大鼠毒性实验，通过实验相关的生化指标和组织切片结果表明，四甲氧基棉酚会影响大鼠肝脏组织的形态结构，造成肝损伤；利用代谢组学实验阐述小分子代谢物含量变化，对结果进行分析得到：四甲氧基棉酚影响机体的糖有氧氧化、糖酵解以及能量代谢过程，在导致脂类代谢紊乱的同时引起肝组织损伤，并破坏肠道环境，致使肠道免疫功能异常；建立专属性强、灵敏度高的HPLC法检测棉籽油中主要游离棉酚降解产物四甲氧基棉酚含量方法；最后，对新疆地区市售棉籽油样品进行游离棉酚、四甲氧基棉酚含量调查，准确掌握目前市场上销售的棉籽油中游离棉酚脱毒情况，根据所采集95批棉籽油样品检测，有54批样品检出四甲氧基棉酚，含量在0.026-1.513 μg/mL，表明四甲氧基棉酚含量较低，可能不足以对消费者的健康造成威胁。本课题的研究工作能够对新疆地区棉籽油中游离棉酚降解产物的污染提供科学的评价方法，同时为新疆地区棉籽油的生产和监管提供科学有效的检测方法，对保障人民身体健康等方面都将起到重要的意义。