Influence of Extraction Solvent on the Phenolic Profile and Bioactivity of Two Achillea Species.

The phenolic composition, as well as the antioxidant and antimicrobial activities of two poorly investigated Achillea species, Achillea lingulata Waldst. and the endemic Achillea abrotanoides Vis., were studied. To obtain a more detailed phytochemical profile, four solvents with different polarities were used for the preparation of the plant extracts whose phenolic composition was analyzed using UHPLC-MS/MS (ultra-high performance liquid chromatography-tandem mass spectrometry). The results indicate that both of the investigated Achillea species are very rich in both phenolic acids and flavonoids, but that their profiles differ significantly. Chloroform extracts from both species had the highest yields and were the most chemically versatile. The majority of the examined extracts showed antimicrobial activity, while ethanolic extracts from both species were potent against all tested microorganisms. Furthermore, the antioxidant activity of the extracts was evaluated. It was found that the ethanolic extracts possessed the strongest antioxidant activities, although these extracts did not contain the highest amounts of detected phenolic compounds. In addition, several representatives of phenolic compounds were also assayed for these biological activities. Results suggest that ethanol is a sufficient solvent for the isolation of biologically active compounds from both Achillea species. Moreover, it was shown that the flavonoids naringenin and morin are mainly responsible for these antimicrobial activities, while caffeic, salicylic, chlorogenic, p-coumaric, p-hydroxybenzoic, and rosmarinic acid are responsible for the antioxidant activities of the Achillea extracts.

Use of seed priming to improve Cd accumulation and tolerance in Silene sendtneri, novel Cd hyper-accumulator.

Changes in the environment as a result of industrialisation and urbanisation impact negatively on plant growth and crop production. Cadmium (Cd) is one of the most dangerous metals that enters the food chain, with toxic effects on plants and human health. This study evaluated the potential of Silene sendtneri as a novel hyperaccumulator and the role of seed priming in tolerance and accumulation rate of Cd. The effect of different priming agents on germination performance, root growth, seedling development, metal uptake and accumulation, antioxidant defences including enzymatic and non-enzymatic antioxidants has been assessed. Seed priming using silicic acid, proline alone or in combination with salicylic acid- enhanced germination, seedling development, and root growth under Cd stress. The same priming treatments induced an increase of water content in shoots and roots when plants were exposed to Cd. The enzymatic antioxidant response was specific for the priming agent used. An increase in ferulic acid and rutin in shoots was related to the increase of Cd concentration in the medium. The concentration of malic and oxalic acid increased significantly in shoots of plants grown on high Cd concentrations compared to low Cd concentrations. Silene sendtneri can accumulate significant levels of Cd with enhanced accumulation rate and tolerance when seeds are primed. The best results are obtained by seed priming using 1% silicic acid, proline and salicylic acid.

Phenolic compounds and bioactive properties of Verbascum glabratum subsp. bosnense (K. Malý) Murb., an endemic plant species.

Detailed analysis of phenolic composition and antioxidant and antimicrobial activities of Verbascum glabratum subsp. bosnense (K. Malý) Murb., an endemic species of southeastern Dinaric Alps was performed for the first time. The phenolic composition measured via UHPLC-MS/MS of four extract with different polarity suggested this plant species is very rich in both phenolic acids and flavonoids. Ethanol extract was chemically the most versatile containing 12 compounds with quercitrin and rosmarinic acid as the majors, while water extracts were rich in 4-hydroxybenzoic acid, salicylic acid, morin, and apigenin. All extracts showed high antioxidant potential measured spectrophotometrically with IC50 values ranging 0.139 - 0.021 mg/mL. Antimicrobial testing using agar diffusion test showed that ethanol extract was the most potent against all tested organisms. Also, these activities are correlated with the content of phenolic compounds, which suggest they are active ingredients of the extracts.

Total phenolic and flavonoid contents, antioxidant and antimicrobial activities of Alnus glutinosa (L.) Gaertn., Alnus incana (L.) Moench and Alnus viridis (Chaix) DC. extracts.

The objective of this study was to determine total phenolic and flavonoid contents, antioxidant and antimicrobial activities of methanolic extracts from the leaves and barks of three Alnus species. The phenolic and flavonoid contents of extracts were determined spectrophotometrically using Folin-Ciocalteau and aluminium chloride methods, respectively. In addition, antioxidant activity of the extracts was determined using 1,1-diphenyl-2-picrylhydrazyl radical scavenging method. The antimicrobial activity was performed by disc diffusion assay against six reference bacterial strains including Gram-negative and Gram-positive bacteria and two fungal strains. Extract of Alnus viridis bark contained the highest amounts of total phenolics (780 mg CAT/g), while extract of A. viridis leaves had the highest amount of flavonoids (30.01 mg RUT/g). All extracts showed antioxidant activity higher than thymol, which was used as a positive probe. The largest diameters of inhibition zone (25 mm) were recorded with Bacillus subtilis 168 M and Staphylococcus aureus ATCC 6538.

Cytotoxic and genotoxic activity of some Helleborus species.

Despite their known toxic properties, various Helleborus species are used as medicaments in folk medicine to treat some diseases and health conditions. As the main mechanism of many cytostatic drugs is based on their cytotoxic activity, there is potential for the toxicity of hellebore to be used in anticancer therapy. This study tested the geno- and cytotoxic effects of extracts of three hellebore taxa (Helleborus odorus, Helleborus multifidus and Helleborus hercegovinus) on meristemic onion (Alliumcepa L.) cells and human lymphocytes. Treatments with Helleborus extracts induced cytotoxic and cytostatic effects in meristemic onion cells as well as in cultivated cytokinesis-blocked human lymphocytes. Cytokinesis-block micronucleus cytome assay indicated that treatments with hellebore extracts induce genotoxic effects in human lymphocytes, and that the significant mechanism of their antiproliferative activity is apoptosis induction.

Antioxidative and antitumor properties of in vitro-cultivated broccoli (Brassica oleracea var. italica).

CONTEXT: Broccoli [Brassica oleracea L. var. italica Plenck. (Brassicaceae)] contains substantial quantities of bioactive compounds, which are good free radical scavengers and thus might have strong antitumor properties. Enhancing production of plant secondary metabolites could be obtained with phytohormones that have significant effects on the metabolism of secondary metabolites. In that manner, in vitro culture presents good model for manipulation with plant tissues in order to affect secondary metabolite production and thus enhance bioactive properties of plants. OBJECTIVE: Estimation of the antioxidative and antitumor properties of broccoli cultivated in different in vitro conditions. MATERIALS AND METHODS: In vitro germinated and cultivated broccoli seedlings, as well as spontaneously developed calli, were subjected to Soxhlet extraction. Antioxidative activity of the herbal extracts was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)) radical method. Antitumor properties of the extracts were determined using crown-gall tumor inhibition (potato disc) assay. RESULTS: Three, 10, 20, and 30 days old broccoli seedlings, cultivated in vitro on three different Murashige-Skoog media, two types of callus, and seedlings from sterile filter paper were used for extraction. In total, 15 aqueous extracts were tested for antioxidative and antitumor potential. Three day-old seedlings showed the highest antioxidative activity. Eleven out of 15 aqueous extracts demonstrated above 50% of crown-gall tumor inhibition in comparison with the control. Tumor inhibition was in association with types and concentrations of phytohormones presented in growing media. DISCUSSION AND CONCLUSIONS: It is demonstrated that phytohormones in plant-growing media could affect the bioactive properties of broccoli either through increasing or decreasing their antioxidative and antitumor potential.

Antioxidant and antiproliferative activities of Helleborus odorus Waldst. & Kit, H. multifidus Vis. and H. hercegovinus Martinis.

This study was undertaken in order to evaluate possible antioxidative and antiproliferative activities of three Helleborus taxa. The dry leaves and roots of three Helleborus taxa were extracted with ethanol and water. A phytochemical evaluation of the selected extracts was performed using spectrophotometric methods and a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity assay was used for measuring the antioxidative activity of extracts. The antiproliferative activity of the three Helleborus taxa was studied using Burkitt's lymphoma B cells (BJAB) cell lines. The phytochemical evaluation showed that the leaves contain high levels of total phenolic and flavonoid content. Results from the DPPH assay indicated that the activity of the ethanol and water extracts of the leaves was higher than that of positive control (thymol). Extracts from the roots of H. odorus also displayed higher antioxidant activity than the positive probe, while H. mulifidus and H. hercegovinus root extracts were less effective. A statistically significant correlation between total phenolic content and antioxidative properties indicates that these compounds contribute to the antioxidant activity. The highest percentage of cell growth inhibition was observed when testing the water root extracts of H. multifidus (50.14%) and H. hercegovinus (49.04%). In contrast, the water leaf extract of H. hercegovinus exhibited the lowest inhibition of cell growth (8.59%), although it showed strong antioxidant activity.