Smith-Barbaro P, Hanson D, Reddy B S
J Natl Cancer Inst. 1981 Aug;67(2):495-7.
The percent of the carcinogen 1,2-dimethylhydrazine (DMH) bound to a variety of fibers, such as wheat bran, corn bran, citrus pulp, citrus pectin, and alfalfa, was examined at pH values ranging from 1 to 12. The percent of DMH bound to wheat bran increased from 4% at PH 1 to 55% at pH 2 to 77% at pH 12. A sharp rise in carcinogen binding to corn bran occurred between pH 5% of the DMH was bound and pH 8 where 51% of the DMH was bound. The percent of DMH bound to dehydrated citrus pulp also increased as the pH increased with 10% binding observed at pH 1 and with 57% binding observed at pH 12. Between pH 2 and pH 7, the percent of DMH bound to pectin decreased from 60 to 11%. As the pH became more basic, the percent of DMH bound to pectin increased to 42% at pH 12. The sharpest rise in the percent of DMH bound to alfalfa meal occurred between pH 10.5 and pH 12.0. Results from this experiment showed that the affinity to various types of dietary fibers for the colon carcinogen DMH was differentially affected by pH. These results suggested that the protective effect of certain types of dietary fiber against chemically induced colon cancer my in part be attributed to enhanced carcinogen binding by dietary fiber in the colon.
研究了在pH值为1至12的范围内，致癌物1,2 - 二甲基肼（DMH）与多种纤维（如麦麸、玉米麸、柑橘果肉、柑橘果胶和苜蓿）结合的百分比。DMH与麦麸结合的百分比从pH 1时的4%增加到pH 2时的55%，再到pH 12时的77%。DMH与玉米麸结合率在pH 5（5%的DMH结合）至pH 8（51%的DMH结合）之间急剧上升。DMH与脱水柑橘果肉结合的百分比也随着pH值的升高而增加，在pH 1时观察到10%的结合率，在pH 12时观察到57%的结合率。在pH 2至pH 7之间，DMH与果胶结合的百分比从60%降至11%。随着pH值变得更碱性，DMH与果胶结合的百分比在pH 12时增加到42%。DMH与苜蓿粉结合百分比上升最显著的情况发生在pH 10.5至pH 12.0之间。该实验结果表明，结肠致癌物DMH对各种膳食纤维的亲和力受pH值的影响不同。这些结果表明，某些类型的膳食纤维对化学诱导的结肠癌的保护作用可能部分归因于膳食纤维在结肠中增强了致癌物的结合。
