Role of Nigella sativa and a number of its antioxidant constituents towards azoxymethane‐induced genotoxic effects and colon cancer in rats

Abstract

This study examined the chemopreventive effect of Nigella sativa and some of its antioxidant constituents on a number of colon cancer biomarkers in rats induced with azoxymethane (AOM). Sixty male Sprague-Dawley rats were randomly assigned into ten subgroups: vehicle (1-5) and experimental (6-10). The rats in each group were fed one of the following diets: basal diet, (200 mg/kg) Nigella sativa, (0.2 mg/kg) selenium, (1.2 mg/kg) all-trans-retinol plus (100 mg/kg) DL-alpha-tocopherol and (10 mg/kg) thymoquinone, respectively. Only rats in subgroups 6-10 were injected with AOM (15 mg/kg) once per week for 2 weeks. Both groups were fed their respective diets for 5 weeks. Then they were killed and examined for colonic aberrant crypt foci (ACF). Our result showed that only vitamin supplementation was effective on ACF. Nigella sativa revealed inhibitory effects only on DNA damage (day 34) in the AOM-treated rat group. Alternatively, selenium, thymoquinone and vitamins inhibited the MDA content in the liver. Although the exact mechanisms involved in the protective role of Nigella sativa against the initiation of colon carcinogenesis are not clearly understood, the results suggest that its inhibitory effects might depend on the combined competitive inhibition of various antioxidant constituents of this plant.

Review on Molecular and Therapeutic Potential of Thymoquinone in Cancer

“…In another study, Al-Johar et al (21) reported modulation by TQ of aberrant crypt foci in rats induced by azoxymethane.…”

“…Thus far, studies cited in the literature have suggested that TQ protects the kidney against ifosfamide, mercuric chloride, cisplatin, and doxorubicin-induced damage by preventing renal GSH depletion and antilipid peroxidation product accumulation, thereby improving renal functioning (18–20). TQ supplementation in diet of Sprague-Dawley rats inhibited malonaldehyde content in liver, which suggests reduction in the lipid peroxide formation (21). Furthermore, TQ ameliorated hepatotoxicity of carbon tetrachloride as seen by the significant reduction of the elevated levels of serum enzymes and significant increase of the hepatic GSH content (22–24).…”

Accumulation of Mercury in Ovaries of Mice After the Application of Skin-lightening Creams

“…Our previous study [65] showed that selenium is one of the constituents of basal diet (0.223±0.009 µg/g) fed to experimental animals in our institution. Even though, selenium was not measured in this study, we should take into consideration the possible interaction role of mercury-selenium in the accumulations and the selenium antagonistic effect on the toxic effect of mercury on ovary or other tissues.…”

Comparing the Effects of Cumin, Peppermint, and Milk of Magnesia on Gastrointestinal Complications after Caesarean Section

“…studies, from which hypotension (Khattab & Nagi, 2007;Dehkordi & Kamkhah, 2008), hypoglycemic (Kaleem et al, 2006;Meddah et al, 2009), hypolipidemic (Bamosa, Ali, & Al-Hawsawi, 2002), antioxidant (Uz et al, 2008;Kanter, Coskum, & Uysal, 2006) anti-inflammatory (Al-Ghamdi, 2001) and anti-tumor (Mbarek, 2007;Al-Johar, 2008) effects can be noted. It is also used as diuretic, anti-parasitic and carminative agent (Ali & Blunden, 2003).…”