【作者】 傅伟昌；

【导师】 汤坚；

【作者基本信息】 江南大学 ， 食品科学， 2009， 博士

【摘要】 癞葡萄（MCV）是苦瓜的一个变种。癞葡萄籽油的主要成分是甘油三酯（TG, 85.43%）,主要特征脂肪酸（FA）为共轭亚麻酸（CLn, 55.13%）,所含三种CLn异构体以α-桐酸为主（51.54%）;癞葡萄籽油是多种含CLn的TG的混合物。目前国内外对苦瓜籽油及其特征FA的抗结肠肿瘤的活性已作了大量研究,但迄今为止,关于苦瓜籽油中的TG的抗肿瘤活性研究仍为空白。人们普遍认为FA是油脂的抗肿瘤功效的最基本功能单元,完全忽略了油脂的TG层次对抗肿瘤功效的贡献;还认为TG在人体内一定先水解成游离脂肪酸（FFA）才被吸收利用,所以认为TG结构对其功效是不重要的,FA组成才是关键的。本论文比较了含CLn的MCVTG与FFA形式的CLn的抗某种肿瘤的功效,研究了含CLn的MCVTG的结构与抗肿瘤功效的关系。本论文分析了癞葡萄籽的化学组成,其中癞葡萄籽仁的含油率为32%;测试了癞葡萄籽油的基本化学性质;分析了癞葡萄籽油的FA组成,鉴定了主要特征FA。发现AOCS推荐的猪胰脂酶定向水解法和猪胰脂酶定向水解—2-溴苯乙酮衍生化—HPLC法不适于分析癞葡萄籽油的FA分布;癞葡萄籽油混合TG的¹³C-NMR分析揭示癞葡萄籽油中TG的sn-2位置主要由CLn占据。从桐油中分离得到纯的三α-桐酸甘油酯,补充了文献中缺少的由α-桐酸构成的AAA型TG的¹³C-NMR数据。癞葡萄籽油混合TG经NARP-HPLC分离,用APCI-MS进行初步结构鉴定,共分离鉴定出20种TG,TG中都含有CLn,以CLn占据sn-2位的TG为主;用HPLC分离制备的两个纯的癞葡萄籽油TG组分,再用¹³C-NMR法分析它们的FA分布,所得结果与APCI-MS结构鉴定结果一致。采用酶促酯交换法合成了结构预计为SSCLn的TG,它是癞葡萄籽油中的结构为SCLnS的TG的位置异构体,也用APCI-MS鉴定其结构,结果正如预计,证明了APCI-MS法鉴定TG结构的适用性。选择α-桐酸作为药物对照组,采用体外细胞培养方法,通过体外试验,考察了癞葡萄籽油混合TG和六组癞葡萄籽油分离TG对五种人体消化系统肿瘤细胞增殖的影响,初步探讨了TG的结构或组成与油脂的抗肿瘤功效的关系。六组不同MCVTG分别对5个人体消化系统的肿瘤细胞系的细胞增殖有大小不一的阻抗效果,除了对结肠癌细胞增殖的抑制作用不如α-桐酸外,癞葡萄籽油中含CLn的TG对另4个人体肿瘤细胞系的增殖抑制作用都比α-桐酸强,提示FFA状态的CLn比TG状态的功效弱。对正常肝细胞增殖虽有抑制作用,但强度不高;MCVTG及α-桐酸对肿瘤细胞的增殖的影响均有明显的量效关系,但时间-效应关系不明显。综合来看,结构为SCLnS的MCVTG抗人体肿瘤的活性最佳,且对多种肿瘤细胞增殖有抑制作用,尤其是在低浓度时对人胃癌细胞株SGC-7901、人口腔癌细胞KB和人肝癌细胞株Bel-7402作用显著,而SCLnS在MCVO中的含量较少。本文以MCVO或桐油为原料,在1, 3位特异性脂肪酶的定向催化下,利用酯交换反应使MCVO或桐油中的TG向SCLnS转化,并优化了酶促酯交换反应条件。SSCLn和SCLnS抗肿瘤功效的比较还不能证明CLn在甘油骨架上的位置与功效有关。MCVTG可能最终通过CLn起抗肿瘤作用,即CLn的脂质过氧化机制是MCVTG抗肿瘤的基础;但MCVTG这种CLn的甘油三酯形态可延缓CLn的氧化率,保护CLn的生理功能,从而最大限度地发挥抗肿瘤功效。从脂肪酸组成、TG组成与结构、相近组分对各细胞株的细胞增殖抑制作用等方面比较了MCVTG和桐油TG,有可能帮助我们认识MCVTG抗肿瘤的结构性因素,同时有可能促进开发桐油中含量巨大的α-桐酸资源。采用溶剂分提法（无水乙醇-正己烷混合溶剂）富集了结构为SCLnCLn的癞葡萄籽油TG组分,该组分占癞葡萄籽油TG的60%左右,可经NARP-HPLC分离纯化得到单一组分,对人胃癌细胞株SGC-7901增殖具有很强的抑制作用。更多还原

【Abstract】 Momordica charantia L. var. abbreviata Ser. （MCV） is identified as a species of Momordica charantia. （MC）. Triacylglycerols （TG） are the major components （85.43%） of the seed oil of MCV （MCVO）. Conjugated linolenic acids （CLn, 55.13%） are the characteristic fatty acids （FA） of MCVO andα-eleostearic acid is the major isomer in three isomers of CLn in MCVO （51.54%）. MCVO is a mixture of TGs containing CLn.Many investigations have focused their attentions on the anti-colon carcinogenesis activities and mechanisms of the seed oil of MC andα-eleostearic acid in the world recently. However, there are almost no reports concerning the inhibitory effect of TGs in MC or MCV on tumor cells. It is generally accepted that FAs are basic units of lipids and the inhibitory effect of lipids on tumor cell lines is attributable to FAs. The inhibitory effect of TGs is completely neglected. Another common thought that prevents the investigation of active effect of TGs is that TGs must be degraded to free fatty acids （FFA） to pass into the mucosal cells and FA composition is commonly regarded as the key factor for active effects of lipids. The anticancer effects of MCVTG, which contain CLn, were compared with that of CLn, which is in FFA form, in this paper. The connections between structures of MCVTGs and their anti-carcinogenesis activities were also studied.In this paper, the chemical components of the seed of MCV were analyzed and the lipids content was tested to be 32.04%; the basic chemical characters and the FA compositions of MCVO were also analyzed; the major characteristic FA of MCVO was identified asα-eleostearic acid.It was found that the method of pancreatic lipase recommended by AOCS and its corrected method are not the appropriate methods for the distribution analysis of FAs in MCVO. The sn-2 position of glycerol backbone of TGs in MCVO was mainly occupied by CLn according to the ¹³C-NMR data. The ¹³C-NMR data of AAA type TG containingα-eleostearic acid, which was separated from tung oil, were supplemented.With TGs mixture of MCVO separated by NARP-HPLC and their structures identified by APCI-MS, twenty kinds of TGs with CLn mainly occupying sn-2 position were obtained. The FA distribution of two kinds of pure TGs was analyzed by ¹³C-NMR and the result was consistent with that of APCI-MS. A positional isomer of an individual TG in MCVO—namely SCLnS, was synthesized by transesterification, and then the new compond was identified as SSCLn by APCI-MS. This shows APCI-MS is the appropriate method for TGs structure identification.Withα-eleostearic acid as control, the cytotoxic effects of TGs mixture and TGs separated from MCVO on five cultured human tumor cell lines were investigated to illustrate the connections between the effect and the component and structure of TGs. Six groups of MCVTG displayed different intenseness of cytotoxic effect on five human tumor cell lines. MCVTG are more cytotoxic thanα-eleostearic acid on four cell lines except for LS-174-T, suggesting that the anti-cancer effect of CLn in its FFA form is weaker than its TG form. MCVTG andα-eleostearic acid displayed weak cytotoxic effect on normal cell line of L02. They inhibited cells growth in a dose-dependent manner, but the time-dependent is not significant. On the whole, an individual TG, whose structure was identified as SCLnS, displayed the most intense cytotoxic effect on several tumor cell lines, e.g. SGC-7901, KB, and Bel-7402, especially at low concentrations. The difference of anti-cancer effct between SSCLn and SCLnS is not significant to deduce the conclusion that the different positions of glycerol backbone occupied by CLn can affect the anti-cancer effct of TGs. The cytotoxic action of TGs containing CLn against human tumor cells might be attributable to conjugated trienoic structure of CLn, with mechanism of lipid peroxidation. But oxidation rate of CLn can be slowed by triacylglycerol esterification and the bioactive center of CLn can be protected before absorption.MCVTG was compared with TGs of tung oil from the FAs composition, the component and structure of TGs, and the cytotoxic effect of similar TGs groups on tumor cell lines. The work probably gives us hints to illustrate the structure factors of TGs for the anti-cancer effect of MCVTG and probably promotes the development ofα-eleostearic acid sources in tung oil.SCLnCLn is the major component of MCVTG （approximately 60% of total TGs）. It displayed most intense cytotoxic effect on SGC-7901 cell line and is a pure material isolated by NARP-HPLC. It was enriched by method of fractionation with mixed solvent of anhydrous ethanol and hexane.SCLnS was minor conponent in MCVO. TGs in MCVO or tung oil were converted to SCLnS by transesterification catalyzed by sn-1,3 lipase.更多还原