Study of apoptosis induced by Calendula officinalis extract on experimental colon carcinoma in rats

In vitro studies have demonstrated the anticancer effect of Calendula officinalis extract on tumor cell line derived from colorectal cancers. The inhibition ranged from 70-100%. The aim of this study was to evaluate the apoptosis in epiththelial displastic colon cells following treated with Calendula officinalis extract. In this experimental study, 56 wistar male rats with age of 12 weeks and 200-300g weight were allocated into two equal groups of treatment and control. For induction of colorectal carcinoma, these two groups were given 1,2-dimethylhydrazine (40mg/kg), as subcutaneous injection, twice a week for two weeks. Treatment group also was treated with Calendula officinalis extract (200mg/kg/day) orally for 10 weeks. After 10 weeks, distal parts of colon tissue were biopsied in both groups and 3-4 micron tissue section was prepared through TUNEL staining method. Immunohistopathological study reveals that apoptotic cells of displastic colon epithelial cells in treatment group were higher than control group. Mean difference between treatment and control groups were statistically significant (p<0.01). This study indicated that Calendula officinalis extract would be induced apoptosis of displastic colon cells in experimental colorectal carcinoma of rats.