Abstract:
Objective To investigate the chemopreventive effects of mustard seed(MS) on azoxymethane(AOM)-induced colorectal tumor in mice, and explore the anticancer mechanisms of MS based on free radical reactions during tumorigenesis.
Methods A total of 60 Kunming mice were randomly divided into four groups: AOM alone, AOM+5%MS, AOM+10%MS, and untreated control.The incidence of colorectal tumor in each group was determined.A colorimetric assay was used to detect the activity of antioxidant enzymes(SOD, CAT, and GSH-PX) and levels of the lipid peroxidation product malondialdehyde(MDA) in the serum of all mice.
Results No tumorous lesion was found in the untreated control group.However, the tumor incidences in the other three groups were statistically significant(χ2=6.607, P=0.048, P < 0.05).The tumor burdens(number of tumors per mouse) were 2.20 ± 1.21 in the AOM alone group, 1.07 ± 1.10(P < 0.05) in the AOM+5%MS group, and 0.67 ± 0.89(P < 0.05) in the AOM+10%MS group.The activities of the serum anti-oxidases SOD, CAT, and GSH-PX were significantly lower in the AOM alone group than in the control, and the difference was significant(P < 0.05).The activities of serum SOD, CAT, and GSH-PX were significantly higher in the AOM+10%MS group than in the AOM alone and AOM+5%MS groups(P < 0.05).The serum MDA content was significantly higher in the AOM alone group than in the control group(P < 0.05).The serum MDA content was significantly lower in the AOM+10%MS group than in the AOM alone and AOM+5%MS groups(P < 0.05).
Conclusion MSs exert chemo-preventive activities against AOM-induced colorectal cancer in mice, and can reduce the tumor incidence and average number of tumors.With increased MS concentration, the preventive effect on colorectal cancer strengthens.Thus, MSs can enhance the in vivo antioxidant ability and free radical-scavenging enzyme activity.The preventive mechanism of MSs on colorectal cancer may be related to its antioxidant activity, which can prevent genetic mutations and tumor incidence by reducing free radical damage to cells.