The antifungal activity of the saponin-rich fractions (SFs) from Medicago sativa (aerial parts and roots) and Saponaria officinalis (used as a well-known source of plant saponins) against Candida albicans reference and clinical strains, their yeast-to-hyphal conversion, adhesion, and biofilm formation was investigated. Direct fungicidal/fungistatic properties of the tested phytochemicals used alone, as well as their synergy with azoles (probably resulting from yeast cell wall instability) were demonstrated. Here, to the best of our knowledge, we report for the first time the ability of saponin-rich extracts of M. sativa and S. officinalis to inhibit C. albicans germ tube formation, limit hyphal growth, reduce yeast adherence and biofilm formation, and eradicate mature (24 h) Candida biofilm. Moreover, M. sativa SFs (mainly obtained from aerial parts), in the range of concentrations which were active modulators of Candida virulence factors, exhibited low cytotoxicity against the mouse fibroblast line L929. These properties seem to be very promising in the context of using plant-derived SFs as potential novel antifungal therapeutics supporting classic drugs or as ingredients of disinfectants.

Context: The main source of bufadienolides is toad venom; however, plants such as members of Kalanchoe Adans. (Crassulaceae) genus may also synthesize these bioactive substances. Objective: This is the first study on antioxidant effects and cytotoxicity of bufadienolide-rich fraction isolated from Kalanchoe daigremontiana Raym.-Hamet & H. Perrier. Materials and methods: The methanolic fraction was extracted from the plant roots and contained 0.48 mg bufadienolides/mg of dry mass (11α,19-dihydroksytelocinobufagin, bersaldegenin-1-acetate, bersaldegenin-1,3,5-orthoacetate, 19-(acetyloxy)-3β,5β,11α,14-tetrahydroxyl-12-oxo-bufa-20,22-dienolide and 19-(acetyloxy)-1β,3β,5β,14-tetrahydroxyl-bufa-20,22-dienolide, mainly). The cytotoxicity of K. daigremontiana fraction was evaluated in an in vitro experimental model of blood platelets. The viability of blood platelets was determined on the basis of a release of lactate dehydrogenase. Results: The fraction scavenged DPPH^• radicals, with EC₅₀ of 21.80 μg/mL. Studies on an experimental model of blood plasma under peroxynitrite-induced oxidative stress revealed that the plant preparation had moderate antioxidant properties. Levels of 3-nitrotyrosine and thiol groups indicated that the protective effect of K. daigremontiana was significant mainly for its concentration of 50 μg/mL. No effect was found in prevention of oxidation of low-molecular plasma thiols (glutathione, cysteine and cysteinylglycine). Simultaneously, measurements of lipid hydroperoxides and thiobarbituric acid-reactive substances (TBARS) indicated that the examined fraction might be effective antioxidant at broader concentration range, that is 1–5 and 25–50 μg/mL for hydroperoxides and TBARS generation, respectively. No cytotoxicity was observed at the concentration range of 1–50 μg/mL. Conclusions: Based on the obtained results, we suggest that antioxidant activity may additionally contribute to beneficial properties of K. daigremontiana-derived extracts.

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.

An aqueous extract from the roots of Kalanchoe daigremontiana turned out to be a rich source of bufadienolides. The existing literature data relate mainly to the aerial parts of Kalanchoe but there is no information about the metabolic profile of the roots, which are also used in traditional medicine. Our investigation concerning the roots of K. daigremontiana led to the isolation and characterization of eight new bufadienolides, namely 1β,3β,5β,14β,19-pentahydroxybufa-20,22-dienolide (1), 19-(acetyloxy)-1β,3β,5β,14β-tetrahydroxybufa-20,22-dienolide (2), 3β-O-α-l-rhamno-pyranosyl-5β,11α,14β,19-tetrahydroxybufa-20,22-dienolide (3), 19-(acetyloxy)-3β,5β,11α,14β-tetrahydroxybufa-20,22-dienolide (4), 3β,5β,11α,14β,19-pentahydroxy-12-oxo-bufa-20,22-dienolide (5), 19-(acetyloxy)-3β,5β,11α,14β-tetrahydroxy-12-oxo-bufa-20,22-dienolide (6), 19-(acetyloxy)-1β,3β,5β,11α,14β-pentahydroxy-12-oxo-bufa-20,22-dienolide (7) and 1β-(acetyloxy)-3β,5β,11α,14β,19-pentahydroxy-12-oxo-bufa-20,22-dienolide (8), together with seven known compounds: 11α,19-dihydroxytelocinobufagin (9), bersaldegenin-1-acetate (10), daigredorigenin-3-acetate (11), bersaldegenin-1,3,5-orthoacetate (12), bryotoxin B (13), bryophyllin B (14) and bersaldegenin (15). The structures were established applying extensive 1D- and 2D-NMR and MS spectroscopic analyses.

Epidemiological data suggest that consumption of whole-grain and bran may help to prevent cardiovascular diseases, diabetes and certain forms of cancer. The beneficial health effects are usually attributed to the presence of dietary fibre and bioactive secondary metabolites, including phenolic acids. Wheat is an important component of the human diet and may be a significant source of phenolic antioxidants. To date, few studies have investigated the effect of various agricultural practices on levels of secondary metabolites in crops. The aim of this work was to determine the phenolic acid content in four winter wheat cultivars, grown using conventional and organic agricultural practices. Five phenolic acids were detected by HPLC analyses. Ferulic acid was the predominant phenolic acid in the grain of all tested wheat varieties. The remaining phenolic acids, i.e. sinapic acid, \ud p\ud -coumaric acid, vanillic acid, and \ud p\ud -hydroxybenzoic acid, were present in considerably lower amounts. Significant differences among cultivars in concentration of particular phenolic acids, as well as in the total phenolic acid content were observed. The effect of various agricultural practices on phenolic acid levels in wheat grains was also analysed. Organically grown plants are usually considered to contain more secondary metabolites. In this study, however, organic agriculture did not lead to a significant increase in phenolic acids. Only a small, statistically irrelevant trend towards higher levels of phenolic acids in organic wheat samples was demonstrated