Indian toad (Bufo melanostictus, Schneider) skin extract induces apoptosis and shows cytotoxic effect on Ehrlich ascites carcinoma (EAC) cells

Abstract

Indian toad (Bufo melanostictus) skin extract (TSE) was evaluated for cytotoxic and apoptogenic activities on Ehrlich ascites carcinoma (EAC) cells of EAC bearing Swiss albino male mice. LD50 of TSE was found to be 400 mg kg-1, (i.v.) and 750 mg kg-1, (i.p.) in mice. EAC cells (1-2 ´ 105 / mouse) were inoculated (i.p.) into mice (20.6 ± 0.14 gm) and the status of EAC cell proliferation and viability were studied in control and TSE treated groups. TSE (10, 20, 30 mg kg-1 d-1, i.p. for 10 d) significantly inhibit EAC cell growth in dose dependent manner. TSE (50, 100 mg kg-1 d-1, i.p. for 1 d) significantly reduced the viability of EAC cells and decreased the MTT values compared to control cells. TSE induced DNA breakage was reflected in DNA ladder and single cell gel electrophoresis (comet assay). TSE significantly (P<0.001) increased the number tailed cells and length-width ratio of DNA mass in EAC cells as compared to control. Fluorescent microscopy of TSE treated cells showed significant increase in number of early and late apoptotic cells compared to the control EAC cells. Apoptotic index of TSE treated cells was significantly (P<0.001) higher than that of the control cells. Changes in serum LDH, β2-microglobulin in TSE treated EAC mice and our earlier studies indicated the involvement of immunomodulation which may indirectly be associated with the anticancer activity of TSE.
 Keywords: Toad skin extract; Bufo melanostictus; Ehrlich ascites carcinoma; Cytotoxic agent;