UGT concentrations in human rectal tissue after multidose, oral curcumin

Area of Science:

• Pharmacology
• Gastroenterology

Background:

• Curcumin is a substrate for uridine diphosphate glucuronosyltransferases (UGTs) in vitro.
• Curcumin may induce or inhibit UGT function, suggesting potential drug interactions.

Purpose of the Study:

• To evaluate the effect of oral curcumin on intestinal UGT expression in healthy volunteers.
• To determine if curcumin supplementation alters UGT expression in the colonic mucosa.

Main Methods:

• Healthy volunteers (40-80 years) received 4g of curcumin daily for 30 days.
• Rectal mucosal biopsies were collected at baseline and 30 days for UGT quantification (UGT1A10, UGT2B17) using LC-MS/MS.
• Quantitative targeted absolute proteomics analyzed 14 UGT 2A and 2B isoforms.

Main Results:

• UGT1A10 and UGT2B17 were detected in most paired biopsy samples.
• No significant differences were observed in median UGT1A10 or UGT2B17 concentrations before and after 30 days of curcumin administration (P=0.23 and P=0.24, respectively).
• Other UGTs were below the limit of quantification.

Conclusions:

• Oral curcumin administration for 30 days did not alter rectal mucosal UGT expression in healthy adults.
• Curcumin use is unlikely to modify colonic UGT expression, suggesting a low risk of drug interactions mediated by these enzymes in the distal gut.
• Rectal biopsies may not represent proximal gut UGT expression or curcumin concentrations.