The effect of plant extracts Kalanchoe daigremontiana, and Aloe arborescens on human multiple myeloma cells' viability was investigated. It was shown that plant extracts of kalanchoe and aloe reduced tumor cells' viability by 13 and 46%, respectively. The combination of plant extracts with doxorubicin showed an additive synergism of action, enhancing the antitumor effect. Treatment of multiple myeloma cells with plant extracts led to a decrease in intracellular reduced glutathione level. The intracellular glutathione level decreased by 25% under the action of kalanchoe extract and by 63% under the action of aloe extract. Extracts from kalanchoe and aloe decreased mitochondrial membrane potential by 19 and 53%, respectively. The results of the study showed that kalanchoe extract increased ATPase activity, but aloe extract did not affect the level of ATPase activity. The results showed that plant extracts of kalanchoe and aloe affect tumor cells' metabolism and contribute to their death. It was concluded that herbal extracts Kalanchoe daigremontiana and Aloe arborescens have antitumor activity, and aloe extract is more effective than kalanchoe.
