Favorable Antitumor Activity of Citrus microcarpa B. on Human Colon Adenocarcinoma Tumor Xenografted in Immunosupressed Mice

BACKGROUND: The antitumor activity of Citrus microcarpa B. on HT29 human colon adenocarcinoma tumors xenografted in immunosuppressed mice was determined in this study. OBJECTIVE: The objective of the study was to determine if the crude extract of C. microcarpa B. exhibited antitumor activity against HT29 human colon adenocarcinoma tumors xenografted in immunosuppressed mice. METHODS: Cyclosporine-induced immunosuppressed mice were injected subcutaneously with 106 HT29 cells in the caudo-dorsal area of the back near the base of the tail to induce tumor growth. Tumors were grown for 9 days, and the mice were then administered with C. microcarpa B. (160 and 630 mg/kg) (Group A; n = 4 and B; n = 4) and normal saline solution (Group C; n = 4) intraperitoneally. Tumor volume was measured to assess the change in tumor volume after 24, 48, and 72-hour post-treatment administration. Tumors were then excised and analyzed histopathologically to evaluate the ratio of necrotic area to viable cancer cells in the tumors. RESULTS: Treatment of C. microcarpa B. with a dose of 160 mg/kg (P=0.002) and 630 mg/kg produced a significant decrease in tumor volume with the significance only observed at 72 hours post-treatment. Histopathological analysis showed a considerable decrease in the area of necrosis against viable tumor cells in the treatment of C. microcarpa B. with a dose of 630 mg/kg. CONCLUSION: It can thus be said that C. microcarpa B. is effective in reducing tumor volume, specifically at a dose of 630 mg/kg 72-hours post-treatment.