Identification of Flavonoids and Bufadienolides and Cytotoxic Effects of Kalanchoe daigremontiana Extracts on Human Cancer Cell Lines

Abstract

Kalanchoe species are well-known medicinal plants used in traditional medicine as anti-inflammatory and analgesic remedies. Recently, it has been reported that Kalanchoe plants have cytotoxic properties; however, data on traditional use of these plants in tumor treatment are extremely limited. Kalanchoe daigremontiana is one of the most popular species cultivated in Europe, and it is used, among other things, as a remedy in treating skin injuries and wounds. Studies on the biological activity of this species are scarce, and there is a lack of data on the cytotoxic activity of K. daigremontiana extracts on epithelial cancer cells in the literature. In our present study, we analyzed the phytochemical composition of K. daigremontiana ethanol extract and fractions–water and dichloromethane–by the HPLC-DAD-ESI-MS method and estimated cytotoxic activity of the extracts on human adenocarcinoma (HeLa), ovarian (SKOV-3), breast (MCF-7), and melanoma (A375) cell lines by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, real-time cell analyzer (RTCA), and flow cytometry. We identified 6 bufadienolide compounds and 19 flavonoids, mostly kaempferol, quercetin, isorhamnetin, and myricetin glycosides, of which only 3 flavonoids have been identified in K. daigremontiana to date. Other flavonoids that were characterized in our study have not yet been found in this plant. The ethanol extract and water fraction of K. daigremontiana did not show significant cytotoxic activity on the tested cell lines. In contrast, the dichloromethane fraction showed the strongest activity against all cell lines with IC50 values of ≤ 10 µg/mL. The results indicated that this activity is mainly due to the presence of bersaldegenin-1,3,5-orthoacetate.

Exploring the Use of Bryophyllum as Natural Source of Bioactive Compounds with Antioxidant Activity to Prevent Lipid Oxidation of Fish Oil-In-Water Emulsions

“…It is important to note that flavonols and anthocyanins from Bryophyllum plant extracts are present as glycosylated forms, which represents a significant physiological feature that modulates solubility and the antioxidant activity associated to these compounds in plant tissues [ 37 ]. These findings indicate that Bryophyllum plant extracts contain a complex (heterogeneous) mixture of polyphenols, together with other families of bioactive compounds, which can exert a moderate antioxidant activity, as it is the case of bufadienolides [ 38 , 39 ]. Such compound heterogeneity found in the extracts make difficult the attribution of the antioxidant activity to discrete compounds.…”

Biological activities of leaf extracts from selected Kalanchoe species and their relationship with bufadienolides content

“… *These values were obtained in our previous study (Stefanowicz-Hajduk et al. 2019 , 2020 ). R 2 : The coefficient of determination.…”

“…An important group of compounds comprises flavonoids. In our previous study, we identified 19 flavonoids from K. daigremontiana extract (Stefanowicz-Hajduk et al 2020). They were quercetin, kaempferol, myricetin, isorhamnetin, and patuletin derivatives.…”

“…In our previous investigation, we estimated the cytotoxic effects of ethanol extract and fractions of K. daigremontiana on tumour cells (Stefanowicz-Hajduk et al. 2020 ). In the present study, we additionally show the cytotoxic activity of water extract from K. daigremontiana leaves, as well as the microbiological effect of the ethanol and water plant extracts.…”

“…Water and methanol extracts of this plant also demonstrated the activity on several bacteria strains and fungi (Akinpelu 2000;Ofokansi et al 2005;Chowdhury et al 2011). In contrast, data on biological activities of K. blossfeldiana and K. daigremontiana extracts are scarce (Nahar et al 2008;Sarkar et al 2015;Stefanowicz-Hajduk et al 2019, 2020.…”