Ng T C, Ferguson L R, Harris P J, Watson M E, Roberton A M
Department of Biochemistry, University of Auckland, New Zealand.
Chem Biol Interact. 1992 Apr 15;82(2):219-29. doi: 10.1016/0009-2797(92)90112-x.
The adsorption of mutagens by some dietary fibres has been suggested as one mechanism by which dietary fibres protect against colorectal cancer. It is thought that these dietary fibres carry the mutagen out of the digestive tract, decreasing the effective mutagen concentration to which epithelial cells are exposed. The ability of gastrointestinal mucin to alter the extent to which the hydrophobic mutagen 1,8-dinitropyrene (DNP) adsorbs in vitro onto the insoluble dietary fibre alpha-cellulose, was investigated. It was found that crude and purified human ileal mucins themselves adsorbed DNP and decreased the adsorption of DNP onto alpha-cellulose. Purified mucin which had been treated with trypsin also adsorbed DNP. These studies suggest that in the digestive tract there would be competition for the adsorption of DNP between mucin and insoluble dietary fibres, such as alpha-cellulose. This factor must be considered in predictions about the distribution of hydrophobic, mutagenic carcinogens in the digestive tract and their role in the etiology of colorectal cancer.
一些膳食纤维对诱变剂的吸附作用被认为是膳食纤维预防结直肠癌的一种机制。据认为，这些膳食纤维将诱变剂带出消化道，降低上皮细胞所接触的有效诱变剂浓度。研究了胃肠道粘蛋白改变疏水性诱变剂1,8-二硝基芘（DNP）在体外吸附到不溶性膳食纤维α-纤维素上的程度的能力。发现粗制和纯化的人回肠粘蛋白本身能吸附DNP，并降低DNP在α-纤维素上的吸附。用胰蛋白酶处理过的纯化粘蛋白也能吸附DNP。这些研究表明，在消化道中，粘蛋白和不溶性膳食纤维（如α-纤维素）之间会竞争DNP的吸附。在预测疏水性诱变致癌物在消化道中的分布及其在结直肠癌病因学中的作用时，必须考虑这一因素。
