Evaluation of the cytotoxic effect of the monoterpene indole alkaloid echitamine in-vitro and in tumour-bearing mice.

The cytotoxic effect of various concentrations of echitamine chloride was studied in HeLa, HepG2, HL60, KB and MCF-7 cell lines in-vitro and in mice bearing Ehrlich ascites carcinoma (EAC). Exposure of various cells to different concentrations of echitamine chloride resulted in a concentration-dependent cell killing, and KB cells were found to be most sensitive amongst all the cells evaluated. EAC mice treated with 1, 2, 4, 6, 8, 12 or 16 mg kg-1 echitamine chloride showed a dose-dependent elevation in the anti-tumour activity, as evident by increased number of survivors in comparison with the non-drug treated controls. The highest dose of echitamine chloride (16 mg kg-1) caused toxicity in the recipient mice, therefore 12 mg kg-1 was considered the best cytotoxic dose for its anti-tumour effect. Administration of 12 mg kg-1 echitamine chloride resulted in an increase in the median survival time (MST) up to 30.5 days, which was 11.5 days higher than the non-drug treated control (19 days). Administration of 16 mg kg-1 echitamine chloride to EAC mice resulted in a time dependent elevation in lipid peroxidation that reached a peak at 6 h post-treatment, whereas glutathione concentration declined in a time dependent manner and a maximum decline was reported at 3 h post-treatment. Our study demonstrated that echitamine chloride possessed anti-tumour activity in-vitro and in-vivo.

Modulation of the impaired drug metabolism in sarcoma-180-bearing mice by echitamine chloride.

Echitamine chloride (EC), an indole alkaloid, extracted from the bark of Alstonia scholaris has got highly promising anticancer effect. The effect of this drug on the microsomal drug detoxifying system was studied in sarcoma-180 induced mice. When given sub-cutaneously at a dosage of 5 mg/kg body weight, it was able to alter the impaired drug detoxifying system which was observed in the Sarcoma-180 bearing mice. The levels of microsomal protein, Cyt-P450, Cyt-b5, NADH-Cyt-C-reductase, NADPH-Cyt-C-reductase, and glu-6 phosphatase were determined. The levels of these drug metabolizing enzymes were decreased in S-180 bearing mice. EC treatment corrected to near normal levels of these enzymes and microsomal hemeproteins. In order to understand the mechanism responsible for the decreased protein level and its normalization after treatment with EC, 3H-Phenylalanine incorporation study was carried out. From the results, it is observed that the synthesis of apoproteins is also altered in tumor-bearing animals. All these changes which were observed in tumor-bearing animals were corrected to near normal levels after treatment with EC.

Inhibition of glycolysis and respiration of sarcoma-180 cells by echitamine chloride.

Malignant tumors are known to exhibit high rates of glycolytic activity leading to high production of lactic acid. Hence, neoplastic cells have elevated activity of enzymes responsible for glycolysis. Echitamine chloride, an indole alkaloid extracted from the bark of Alstonia scholaris, has been reported to have a highly promising anticancer activity against fibrosarcoma in rats. In the present study, the effect of echitamine chloride on energy metabolism of S-180 cells is investigated to have a better understanding on the mode of action of echitamine chloride. The effect of echitamine chloride on the mitochondrial and cellular respiration of S-180 cells was studied. Also, the effects on glucose utilization, pyruvate utilization and lactate formation were studied on whole S-180 cells and S-180 cell-free homogenate. The levels of glycolytic enzymes such as hexokinase and lactate dehydrogenase were estimated in which particular emphasis has been laid on hexokinase which occurs both in cytosolic and particulate forms in neoplastic cells. Hence the differential effect of echitamine chloride on the levels of total, cytosolic and particulate hexokinase has been investigated. In conclusion, echitamine chloride affects both cellular and mitochondrial respiration, leading to reduction of the cellular energy pool and thereby resulting in the loss of viability of S-180 cells.

Antitumor effect of echitamine chloride on methylcholonthrene induced fibrosarcoma in rats.

Echitamine chloride a plant alkaloid from Alstonia scholaris has been used to examine the anticancer effects on methylcholanthrene-induced fibrosarcoma. Echitamine chloride dissolved in saline (10 mg/kg body weight) and injected subcutaneously for 20 days in fibrosarcoma rats has exhibited significant regression in tumor growth. The altered activities of plasma and liver transaminases and gamma-glutamyl transpeptidase and lipid peroxidation in fibrosarcoma have been corrected to near normal after echitamine chloride treatment. The decreased liver glutathione content and the lowered activities of glutathione peroxidase, superoxide dismutase and catalase have also been reversed to near normals after echitamine chloride treatment.