Effect of Alstonia scholaris in enhancing the anticancer activity of berberine in the Ehrlich ascites carcinoma-bearing mice.

The chemomodulatory activity of Alstonia scholaris extract (ASE) was studied in combination with berberine hydrochloride (BCL), a topoisomerase inhibitor, in Ehrlich ascites carcinoma-bearing mice. The tumor-bearing animals were injected with various doses of ASE, and 8 mg/kg of BCL (one-fifth of the 50% lethal dose) was combined with different doses of ASE (60-240 mg/kg). The combination of 180 mg/kg of ASE with 8 mg/kg of BCL showed the greatest antitumor effect; the number of tumor-free survivors was more, and the median survival time and the average survival time increased up to 47 and 40.5 days, respectively, when compared with either treatment alone. Similarly, when 180 mg/kg of ASE was combined with different doses of BCL (2-12 mg/kg), a dose-dependent increase in the anticancer activity was observed up to 8 mg/kg of BCL. However, a further increase in the BCL dose to 10 and 12 mg/kg resulted in toxic side effects. The best effect was observed when 180 mg/kg of ASE was combined with 6 or 8 mg/kg of BCL, where an increase in the antineoplastic activity was reported. The efficacy of the combination of 180 mg/kg of ASE was also tested with 6 mg/kg body weight of BCL in various stages of tumorigenesis, and it was effective when given in the early stages, although the efficiency decreased with an increase in the tumor developmental stages.