Colon 1-glucuronidase

The dose-limiting toxicities in irinotecan therapy are severe diarrhea and leukopenia (10). An increased plasma level of SN-38 may be an important mechanism for severe irinotecan toxicities. Biliary SN-38 G excreted into the small intestine is cleaved by bacterial glucuronidases in the colon to regenerate SN-38 therefore, this process is also... 

The ability of MFGM to inhibit intestinal (3-glucuronidase activity was measured by Ito et al. (1993). This enzyme is a product of colonic... 

Redox reactions and hydrolysis are the predominant metabolic conversions triggered by the intestinal microflora. The primary reductive enzymes produced by the intestinal microflora are nitroreductase, deaminase, urea dehydroxylase, and azoreductase. The hydrolytic enzymes are p-glucuronidase, p-xylosidase, p-galactosidase, and ot-L-arabinosidase. Studies conducted by Macfarlane and coworkers have shown that proteolysis can also occur in the colon. More recent findings by the group indicate that bacterial fermentation of proteins in humans could account for 17% of the short-chain fatty acids in the cecum and for 38 /o in the sigmoid and the rectum. ... 

In an in vivo study, Jenab et al. [150] demonstrated the protective effects of flaxseed lignans against colon cancer. This was associated with an increase in P-glucuronidase activity. The total activity of this enzyme correlated positively with total urinary lignan excretion, especially secoisolariciresinol diglycoside, and negatively with the total number of aberrant crypts and the total number of aberrant crypt foci in the distal colon. 

Reddy, B.S., Mangat, S., Weisburger, J.FI., and Wynder, E.L., Effect of high-risk diets for colon carcinogenesis on intestinal mucosal and bacterial beta-glucuronidase activity in F344 rats. Cancer Res., 37, 3533-3536,1977. 

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