Preparation of a Horse Chestnut Extract with a 50% Content of Escin and its Actions on Tumor Cell Proliferation and Isolated Mitochondria

Resumo

Escin-containing horse chestnut extracts and various medicinal formulations are widely used as venotonic agents whose mechanisms of action and intracellular targets remain unknown. Escin is used as an active substance to increase membrane permeability in experiments, and it has more recently been shown to have cytotoxic effects on a number of tumor cell lines. With the aim of increasing the percentage content of active pharmaceutical escin substance in medicinal formulations and studying its mechanism of action, we prepared a horse chestnut extract (HCE) with a 50% escin content. Comparison of the cytotoxic action on HeLa tumor cell cultures showed that at identical concentrations by weight, HCE and reference agent escin had identical cytotoxic effects. At a concentration of 0.003 mg/ml, both substances inhibited HeLa cell viability by more than 80% at 24 h. The cytotoxic effect was not seen when the concentration was reduced four-fold. At equivalent cytotoxic concentrations, the actions of escin in HCE were studied on isolated mitochondria. Both substances were found to increase mitochondrial membrane permeability, to induce mitochondrial swelling, to decrease mitochondrial calcium capacity, and to induce the opening of mitochondrial pores (MPTP). MPTP opening leads to cell death. Escin induced slow and irreversible swelling of mitochondria, while HCE produced rapid and reversible swelling. The MPTP inhibitor cyclosporin completely eliminated the actions of both substances, pointing to the involvement of mitochondria in the pharmacological actions of escin and HCE.