de Kok T M, ten Hoor F, Kleinjans J C
Department of Biological Health Science, University of Limburg, Maastricht, The Netherlands.
Carcinogenesis. 1991 Feb;12(2):199-205. doi: 10.1093/carcin/12.2.199.
Fecapentaenes, highly potent fecal mutagens originating from intestinal bacterial production, have been suggested to play an essential role in the initiation of colorectal cancer. Reviewing the data on fecapentaene occurrence in man, the applied methodologies for fecapentaene extraction and analysis appear to be very inconsistent. Therefore, we compared several methods and developed an optimal extraction and purification procedure for fecapentaene quantification in human feces. This method is based upon a dichloromethane extraction of freeze-dried material with application of a Potter homogenization instrument and subsequent HPLC analysis in combination with photodiode array detection. This system enables us to detect and quantify at least eight forms of fecapentaene-like substances generally occurring in human stool. We suggest that these peaks represent fecapentaene-12 (FP-12) and fecapentaene-14, both with a geometric isomer, as well as fecapentaene analogues that have never been reported before. Applying this methodology on feces of a group of young healthy persons, we were able to detect fecapentaene levels ranging from less than 5 micrograms to 6 mg/kg feces, and in 40% of the samples greater than 1.0 mg/kg feces. The newly identified fecapentaenes represent 21.7% of total fecapentaene concentration. It appears that some fecapentaenes are excreted in higher amounts by females as compared to males. Furthermore, we found that fecal mutagenicity to Salmonella tester strain TA100 appeared lower than hypothesized on the basis of overall fecapentaene contents, and that fecal extracts diminish the mutagenic effect of synthetic FP-12 dramatically. Apparently, optimal conditions for fecapentaene extraction result also in an increased level of co-extracted anti-mutagenic substances. Determination of fecal mutagenicity as an index for fecapentaene excretion or colorectal cancer risk is therefore not suitable. In order to assess the relevance of fecapentaenes in the etiology of colorectal cancer, we suggest that a distinction should be made between relative occurrence and degree of genotoxic effect in situ of the various fecapentaene analogues.
粪便五烯，一种源自肠道细菌产生的高活性粪便诱变剂，被认为在结直肠癌的起始过程中起着至关重要的作用。回顾关于人类粪便中粪便五烯出现情况的数据，用于粪便五烯提取和分析的应用方法似乎非常不一致。因此，我们比较了几种方法，并开发了一种用于定量人类粪便中粪便五烯的最佳提取和纯化程序。该方法基于用波特匀浆器对冻干材料进行二氯甲烷提取，随后进行高效液相色谱分析并结合光电二极管阵列检测。该系统使我们能够检测和定量至少八种通常存在于人类粪便中的类粪便五烯物质。我们认为这些峰代表粪便五烯 -12（FP -12）和粪便五烯 -14，两者都有几何异构体，以及以前从未报道过的粪便五烯类似物。将此方法应用于一组年轻健康人的粪便中，我们能够检测到粪便五烯水平范围从每千克粪便小于5微克到6毫克，并且在40%的样本中大于每千克粪便1.0毫克。新鉴定的粪便五烯占总粪便五烯浓度的21.7%。似乎与男性相比，女性排泄的一些粪便五烯量更高。此外，我们发现粪便对沙门氏菌测试菌株TA100的致突变性似乎低于基于总粪便五烯含量所假设的水平，并且粪便提取物显著降低了合成FP -12的诱变作用。显然，粪便五烯提取的最佳条件也导致共提取的抗诱变物质水平增加。因此，将粪便致突变性作为粪便五烯排泄或结直肠癌风险的指标并不合适。为了评估粪便五烯在结直肠癌病因学中的相关性，我们建议应区分各种粪便五烯类似物的相对出现情况和原位遗传毒性效应程度。
