The spread of phytocomplex application and justification of its selective effects on tumour cells (mainly due to the presence of flavonoids) require research of its cytotoxic and immunomodulatory activity.The goal wa`s to study the direct cytotoxic effect of the phytocomplex and its modulating effect on the cytotoxic activity of the donor's mononuclear blood cells in in vitro experiments.The phytocomplex was a dry extract from marsh cinquefoil, creeping alfalfa and common hop; its main active ingredients were flavonoids. Transplantable monolayer cultures of lung adenocarcinoma, colorectal cancer, erythroblastic leukaemia, and fibroblasts were used as target cells. The cytotoxic activity was assessed using a cytotoxic test based on the selective ability to live cells to reduce MTT (3-[4, 5-dimethyltriazol-2-yl]-2, 5 diphenyltetrazolium bromide) to formazan in mitochondria. Quantitative determination of formazan was performed using spectrophotometry.A direct cytotoxic effect of the phytocomplex in concentrations of at least 2.5 mg/ml on tumour cells has been established. Its modulating effect on the cytotoxic activity of mononuclear blood cells at a concentration of 0.05 mg/ml was shown. The phytocomplex in doses of 0.25 and 0.5 mg/ml increased the killer activity of the mononuclear cells in a diseased person's blood, but did not affect these blood cells in a healthy donor. Incubation of lymphocytes with a phytocomplex for 24 hours increased the cytotoxic activity of mononuclear cells by 20-25%.The direct cytotoxic effect of the phytocomplex and its modulating effect on the cytotoxic activity of mononuclear blood cells in model experiments in vitro have been established.
