Kalanchoe sp. Extracts-Phytochemistry, Cytotoxic, and Antimicrobial Activities.

species are succulents occurring in tropical regions. They have many biological and pharmacological properties. In this study, the cytotoxic and antimicrobial activities of water and dichloromethane fractions obtained from ethanol extracts of three species-, , and were estimated. The cytotoxic effect was assessed on human cancer cell lines-ovarian SKOV-3, cervical HeLa, breast MCF-7, and melanoma A375-by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The antimicrobial activity was estimated on selected Gram-positive and Gram-negative bacteria strains and on . The phytochemical analysis of selected extracts was conducted by LC-QTOF-MS. The obtained results showed that the water fraction of was active both on the tested cancer cells (IC values were 28.28 ± 2.76 and 32.51 ± 0.69 µg/mL on HeLa and SKOV-3, respectively) and bacteria strains (MIC values were 16 and 32 µg/mL on and , respectively). The water fraction of also had a significant effect on and , with MIC values of 32 and 64 µg/mL, respectively. The water fraction of triggered a decrease in mitochondrial membrane potential (MMP) and induced cell cycle arrest in the G2/M phase in the SKOV-3 and HeLa cells. This fraction did not significantly increase cellular oxidative stress level. The DPPH and ABTS assays revealed that the water fraction of had a strong antioxidant effect (IC was 9.44 ± 0.06 and 3.17 ± 0.1 µg/mL, respectively). The phytochemical analysis of the extracts of and revealed the presence of at least 218 main components. The most frequently occurring were flavonol glycosides (31 metabolites), phenylpropanoids (13 metabolites), gallic acid derivatives (13 compounds), benzoic acid derived compounds (14 metabolites), and acyclic alcohol glycosides (16 compounds). In addition, proanthocyanidins were detected mainly in The study indicates that the water fraction of has significant biological potential and can be further investigated towards anticancer and antimicrobial application.