In vivo cytotoxic effects of methanol extract of Convolvulus arvensis on 7-12-dimethyl benz(a)antheracene (DMBA) induced skin carcinogenesis

A current study was conducted to evaluate the possible cytotoxic effect of Asian herb Convolvulus arvensis (methanolic extract), followed by 2 stage skin carcinogenesis protocol by tumor initiator, 7-12-dimethyl benz(a)antheracene (DMBA) and tumor promoter, Croton oil in Swiss albino mice. They induced 100% skin ulceration in carcinogen control and cumulative number of papilloma (CP), tumor yield (TY) and tumor burden (TB) were calculated as 18.20 ± 1.643, 3.640 ± 0.3286 and 3.640 ± 0.3286, respectively. Local application of the extract at 300 mg/kg/day inhibited the tumor incidence up to 20% in 16 weeks and showed a significant decline in continuous group in CP 4.800 ± 6.611 and TY 0.9600 ± 1.322 compared to carcinogen group. For assistance of morphological alteration, biochemical investigations were performed. Extract increased the reduced glutathione (GSH) from 3.286 ± 0.207 to 7.1260 ± 0.4953 μmol/g, superoxide dismutase (SOD) 1.722 ± 0.1262 to 6.5160 ± 0.3710 μmol/g and catalase (CAT) 13.624 ± 0.813 to 18.792 ± 0.714 of H2O2 reduction/mg protein/min and decreased lipid peroxidation (LPO) 7.652 ± 0.1863 to 4.2340 ± 0.5928 nmol/mg levels compared to carcinogen group. Histopathological changes showed papilomatosis and ulceration in carcinogen while acanthosis with normal psychological features in the continuous group. In conclusion, cytotoxic potential of Convolvulus arvensis methanol extract is due to the presence of querecitin, that is, flavonoid that have the ability to capture the reactive oxygen species, over expressions of tumor causing genes and topoisomerase II; its presence was confirmed by high performance of liquid chromatography (HPLC) chromatogram. These investigations may have introduced new phytochemicals that are easily available and effective for cancer prevention.   Key words: Convolvulus arvensis, skin carcinogenesis, tumor, 7-12-dimethyl Benz (a) antheracene (DMBA), croton oil, querecitin.