Zsuzsanna Hajdú

Antiproliferative effect of flavonoids and sesquiterpenoids from Achillea millefolium s.l. on cultured human tumour cell lines

The antiproliferative activities of n‐hexane, chloroform, aqueous‐methanol and aqueous extracts of the aerial parts of the Achillea millefolium aggregate on three human tumour cell lines were investigated by means of MTT assays. The chloroform‐soluble extract exerted high tumour cell proliferation inhibitory activities on HeLa and MCF‐7 cells, and a moderate effect on A431 cells; accordingly, it was subjected to detailed bioactivity‐guided fractionation. As a result of the multistep chromatographic purifications (VLC, CPC, PLC, gel filtration), five flavonoids (apigenin, luteolin, centaureidin, casticin and artemetin) and five sesquiterpenoids (paulitin, isopaulitin, psilostachyin C, desacetylmatricarin and sintenin) were isolated and identified by spectroscopic methods. The antiproliferative assay demonstrated that centaureidin is the most effective constituent of the aerial parts of yarrow: high cell growth inhibitory activities were observed especially on HeLa (IC50 0.0819 µm) and MCF‐7 (IC50 0.1250 µm) cells. Casticin and paulitin were also highly effective against all three tumour cell lines (IC50 1.286–4.76 µm), while apigenin, luteolin and isopaulitin proved to be moderately active (IC50 6.95–32.88 µm). Artemetin, psilostachyin C, desacetylmatricarin and sintenin did not display antiproliferative effects against these cell lines. This is the first report on the occurrence of seco‐pseudoguaianolides (paulitin, isopaulitin and psilostachyin C) in the Achillea genus. Copyright

Bioactivity-guided isolation of antiproliferative compounds from Centaurea arenaria

The antiproliferative effects of n‐hexane, chloroform and aqueous methanol extracts prepared from the whole plant of Centaurea arenaria M.B. ex Willd. were investigated against cervix adenocarcinoma (HeLa), breast adenocarcinoma (MCF7) and skin epidermoid carcinoma (A431) cells, using the MTT assay. The chloroform extract displayed high tumour cell proliferation inhibitory activity (higher than 85% at 10 μg/mL concentration), and was therefore subjected to a bioassay‐guided multistep separation procedure. Flavonoids (eupatilin, eupatorin, 3′‐methyleupatorin, apigenin and isokaempferid), lignans (arctigenin, arctiin and matairesinol), the sesquiterpene cnicin, serotonin conjugates (moschamine and cis‐moschamine), β‐amyrin and β‐sitosterin‐β‐D‐glycopyranoside, identified by means of UV, MS and NMR spectroscopy, were obtained for the first time from this species. The isolated compounds were also evaluated for their tumour cell growth inhibitory activities on HeLa, MCF7 and A431 cells, and different types of secondary metabolites were found to be responsible for the antitumour effects of the extracts; in addition to moderately active compounds (isokaempferid and moschamine), especially apigenin, eupatorin, arctigenin, arctiin, matairesinol and cnicin exert marked antitumour effects against these cell lines. Copyright

Antiproliferative activity of Hungarian Asteraceae species against human cancer cell lines. Part II

The antiproliferative activities of aqueous and organic extracts prepared from 26 Hungarian species of the tribes Cynereae and Lactuceae (Asteraceae) were tested in vitro against HeLa (cervix epithelial adenocarcinoma), A431 (skin epidermoid carcinoma) and MCF7 (breast epithelial adenocarcinoma) cells by using the MTT assay. Of the tested 200 extracts of different plant parts obtained with n‐hexane, chloroform, 50% methanol and water, 16 extracts displayed noteworthy cell growth inhibitory activity (>50% inhibition at a concentration of 10 µg/mL). The IC50 values of these extracts were determined, and their direct cytotoxic effects were measured. High differences between the antiproliferative and cytotoxic activities, demonstrating a real cell proliferation inhibitory activity rather than direct killing effects, were found for some Centaurea, Cirsium, Cichorium, Lactuca, Onopordum and Scorsonera extracts. Copyright

Antiproliferative constituents of the roots of conyza canadensis

Bioassay-guided fractionation of the N-hexane and CHCl₃ phases of the methanol extract of the roots of Conyza canadensis (L.) Cronquist led to the isolation of two new dihydropyranones named conyzapyranone A (1) and B (2), and the known 4 Z,8 Z-matricaria- γ-lactone (3), 4 E,8 Z-matricaria- γ-lactone (4), 9,12,13-trihydroxy-10(E)-octadecenoic acid (5), epifriedelanol (6), friedeline (7), taraxerol (8), simiarenol (9), spinasterol (10), stigmasterol, β-sitosterol, and apigenin. The structures were determined by means of ESIMS and 1D and 2D NMR spectroscopy, including ¹H-¹H COSY, NOESY, HSQC, and HMBC experiments. The isolated compounds were evaluated for their antiproliferative activities and were demonstrated to exert considerable cell growth-inhibitory activity against human cervix adenocarcinoma (HeLa), skin carcinoma (A431), and breast adenocarcinoma (MCF-7) cells. Some of the active components, including 2, 4, and 10, proved to be substantially more potent against these cell lines than against noncancerous human foetal fibroblasts (MRC-5) and can therefore be considered selective antiproliferative natural products.

Bioactivity-Guided Isolation of Cytotoxic Sesquiterpenes and Flavonoids from Anthemis ruthenica

A new eudesmanolide sesquiterpene, sivasinolide 6-O-angelate (1), was isolated from the aerial parts of Anthemis ruthenica together with the known compounds chrysanin (2), tanacin (3), 3 beta-hydroxycostunolide (4), centauridin (5), and centaureidin (6). The compounds were obtained by means of bioactivity-guided fractionation from the CHCl (3) extract of the herb, which displayed high cytotoxic activity. The structures were determined by UV, HR-ESI-MS, and high-field 1D and 2D NMR spectral analyses, affording complete (1)H- and (13)C-NMR assignments for all compounds. The cytotoxic activities of the isolated sesquiterpenes and flavonoids were assessed against cervical adenocarcinoma HeLa, breast adenocarcinoma MCF7, and skin epidermoid carcinoma A431 cells using the MTT assay. It was found that, apart from centaureidin (6), which is extremely active (IC(50) 0.082, 0.13, and 0.35 microM on the HeLa, MCF7, and A431 cell lines, respectively), all these compounds exert high or moderate tumor cell-growth inhibitory activity (IC(50) 3.42-58.15 microM).

Effects of Chelidonium majus extracts and major alkaloids on hERG potassium channels and on dog cardiac action potential — A safety approach

Chelidonium majus or greater celandine is spread throughout the world, and it is a very common and frequent component of modern phytotherapy. Although C. majus contains alkaloids with remarkable physiological effect, moreover, safety pharmacology properties of this plant are not widely clarified, medications prepared from this plant are often used internally. In our study the inhibitory effects of C. majus herb extracts and alkaloids on hERG potassium current as well as on cardiac action potential were investigated. Our data show that hydroalcoholic extracts of greater celandine and its alkaloids, especially berberine, chelidonine and sanguinarine have a significant hERG potassium channel blocking effect. These extracts and alkaloids also prolong the cardiac action potential in dog ventricular muscle. Therefore these compounds may consequently delay cardiac repolarization, which may result in the prolongation of the QT interval and increase the risk of potentially fatal ventricular arrhythmias.

Quality control of maca-containing (lepidium meyenii walp.) dietary supplements

The radish-like hypocotyls of Maca (Lepidium meyenii Walp., Brassicaceae) are widely consumed as common vegetable in the Andean highlands. It is considered as healthy food, rich in carbohydrates and protein, a herbal medicine with a general invigorating reputation and fertility and sexual performance enhancer. The latter is the most popular contemporary application of the plant in Europe. The number and variety of industrial products on the market is increasing. Here we report the development of a simple and reliable analytical protocol for the qualitative and quantitative analysis of maca content of preparations and for the detection of synthetic phosphodiesterase inhibitors. Fourteen products were analysed by the method based on TLC and HPLC-DAD analysis developed by us. Our experiments revealed that beside good-quality products, the majority of the multicomponent preparations did not contain the declared herbal component or the quantity of the measured macamide was very low. Furthermore, one preparation is adulterated with a synthetic phosphodiesterase inhibitor. The presented method is suitable for quality control of L. meyenii products.

Investigation of the Antiproliferative Properties of Natural Sesquiterpenes from Artemisia asiatica and Onopordum acanthium on HL-60 Cells in Vitro.

Plants and plant extracts play a crucial role in the research into novel antineoplastic agents. Four sesquiterpene lactones, artecanin (1), 3β-chloro-4α,10α-dihydroxy-1α,2α-epoxy-5α,7αH-guaia-11(13)-en-12,6α-olide (2), iso-seco-tanapartholide 3-O-methyl ether (3) and 4β,15-dihydro-3-dehydrozaluzanin C (4), were isolated from two traditionally used Asteraceae species (Onopordum acanthium and Artemisia asiatica). When tested for antiproliferative action on HL-60 leukemia cells, these compounds exhibited reasonable IC50 values in the range 3.6–13.5 μM. Treatment with the tested compounds resulted in a cell cycle disturbance characterized by increases in the G1 and G2/M populations, while there was a decrease in the S phase. Additionally, 1–3 elicited increases in the hypodiploid (subG1) population. The compounds elicited concentration-dependent chromatin condensation and disruption of the membrane integrity, as revealed by Hoechst 33258–propidium staining. Treatment for 24 h resulted in significant increases in activity of caspases-3 and -9, indicating that the tested sesquiterpenes induced the mitochondrial pathway of apoptosis. The proapoptotic properties of the sesquiterpene lactones were additionally demonstrated withannexin V staining. Compounds 1 and 2 increased the Bax/Bcl-2 expression and decreased the expressions of CDK1 and cyclin B2, as determined at the mRNA level by means of RT-PCR. These experimental results indicate that sesquiterpene lactones may be regarded as potential starting structures for the development of novel anticancer agents.