Potential Chemoprevention Activity of Pterostilbene by Enhancing the Detoxifying Enzymes in the HT-29 Cell Line

Detoxifying enzymes are present in most epithelial cells of the human gastrointestinal tract where they protectagainst xenobiotics which may cause cancer. Induction of examples such as glutathione S-transferase (GST)and its thiol conjugate, glutathione (GSH) as well as NAD(P)H: quinoneoxidoreductase (NQO1) facilitate theexcretion of carcinogens and thus preventing colon carcinogenesis. Pterostilbene, an analogue of resveratrol, hasdemonstrated numerous pharmacological activities linked with chemoprevention. This study was conducted toinvestigate the potential of pterostilbene as a chemopreventive agent using the HT-29 colon cancer cell line tostudy the modulation of GST and NQO1 activities as well as the GSH level. Initially, our group, established theoptimum dose of 24 hours pterostilbene treatment using MTT assays. Then, effects of pterostilbene (0-50 μM)on GST and NQO1 activity and GSH levels were determined using GST, NQO1 and Ellman assays, respectively.MTT assay of pterostilbene (0-100 μM) showed no cytotoxicity toward the HT-29 cell line. Treatment increasedGST activity in the cell line significantly (p<0.05) at 12.5 and 25.0 μM. In addition, treatment at 50 μM increasedthe GSH level significantly (p<0.05). Pterostilbene also enhanced NQO1 activity significantly (p<0.05) at 12.5μM and 50 μM. Hence, pterostilbene is a potential chemopreventive agent capable of modulation of detoxifiyingenzyme levels in HT-29 cells.