2-2--azino-di-(3-ethylbenzothiazoline)-6-sulfonic-acid and Colorectal-Neoplasms

In our case-control study, we measure the antioxidant status by dosing enzymes involved in oxidant stress in plasma of patients with colorectal and gastric cancer, and in the second step, we investigate the impact of chemotherapy before and after surgery on plasma antioxidant status and polyphenols in patients. Blood serum was collected from patients with stomach and colorectal cancer before conventional treatment, and glutathione peroxidase (GSHPX) enzyme activities and total polyphenols were determined by spectrophotometric methods. In our study, we found a significant decrease in glutathione peroxidase activity in plasma of patients compared with controls (P = 0.02), although we did not find a significant association between total polyphenols and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) or ABTS in plasma of colorectal and stomach cancer compared with control; furthermore, we observed no significant difference in the average plasma polyphenols in patients treated with chemotherapy before and after surgery. We have shown the decrease in GSHPX activity in plasma of cases with colorectal and gastric cancer, and this decrease reflects that the oxidative stress is associated with tumor tract and related to oxidative metabolism; however, no association was found between total polyphenols and ABTS in our study.

Topics: Antioxidants; Benzothiazoles; Colorectal Neoplasms; Female; Glutathione Peroxidase; Humans; Male; Middle Aged; Oxidative Stress; Polyphenols; Stomach Neoplasms; Sulfonic Acids

Oxidative stress has been proposed to be involved in colorectal cancer development. Many dark pigments of plants have potent oxidative stress preventive properties. In this study, unpolished Thai rice was assessed for antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. Red strain unpolished Thai rice was also administered to rats exposed to azoxymethane (AOM) for induction of aberrant crypt foci (ACF). Serum malondialdehyde (MDA) and ferric reducing antioxidant power (FRAP) were investigated for cellular oxidative stress and serum antioxidants, respectively. Red pigment unpolished Thai rice demonstrated high antioxidant activity and was found to significantly and dose dependently decrease the total density and crypt multiplicity of ACF. Consumption of Thai rice further resulted in high serum antioxidant activity and low MDA cellular oxidative stress. Interestingly, the density of ACF was strongly related to MDA at r=0.964, while it was inversely related with FRAP antioxidants (r=-0.915, p<0.001). The results of this study suggest that the consumption of red strain of unpolished Thai rice may exert potentially beneficial effects on colorectal cancer through decrease in the level of oxidative stress.

Topics: Aberrant Crypt Foci; Animals; Antioxidants; Azoxymethane; Benzothiazoles; Biphenyl Compounds; Colorectal Neoplasms; Male; Malondialdehyde; Oryza; Oxidative Stress; Phytotherapy; Picrates; Plant Extracts; Rats; Rats, Sprague-Dawley; Sulfonic Acids; Thiazoles