Isolation of compounds from the roots of Ambrosia artemisiifolia and their effects on human cancer cell lines.

Common ragweed (Ambrosia artemisiifolia L.) is an invasive plant in Europe with spreading use in the contemporary folk medicine. The chemical composition of the above-ground parts is extensively studied, however, the metabolites of the roots are less discovered. By multiple chromatographic purification of the root extracts, we isolated thiophene A (1), n-dodecene (2), taraxerol-3-O-acetate (3), α-linoleic acid (4), (+)-pinoresinol (5), and thiophene E (7,10-epithio-7,9-tridecadiene-3,5,11-triyne-1,2-diol) (6). The 1H NMR data published earlier for 1 were supplemented together with the assignment of 13C NMR data. Thiophene E (6), which is reported for the first time from this species, exerted cytotoxic and antiproliferative effects on A-431 epidermoid skin cancer cells, whereas taraxerol-3-O-acetate (3) and α-linoleic acid (4) had slight antiproliferative effect on gynecological cancer cell lines. Thiophene E (6) and taraxerol-3-O-acetate (3) displayed antiproliferative and cytotoxic effects on MRC-5 fibroblast cells. Thiophene E (6) exerted weak antibacterial activity (MIC 25 µg/mL) on MRSA ATCC 43300, on Staphylococcus aureus ATCC 25923, Escherichia coli AG100 and E. coli ATCC 25922 both thiophenes were inactive. Although the isolated compounds exerted no remarkable cytotoxic or antiproliferative activities, the effects on MRC-5 fibroblast cells highlight the necessity of further studies to support the safety of ragweed root.

Nitro-Oleic Acid in Seeds and Differently Developed Seedlings of Brassica napus L.

Similar to animals, it has recently been proven that nitro-fatty acids such as nitro-linolenic acid and nitro-oleic acid (NO2-OA) have relevant physiological roles as signalling molecules also in plants. Although NO2-OA is of great therapeutic importance, its presence in plants as a free fatty acid has not been observed so far. Since Brassica napus (oilseed rape) is a crop with high oleic acid content, the abundance of NO2-OA in its tissues can be assumed. Therefore, we quantified NO2-OA in B. napus seeds and differently developed seedlings. In all samples, NO2-OA was detectable at nanomolar concentrations. The seeds showed the highest NO2-OA content, which decreased during germination. In contrast, nitric oxide (●NO) levels increased in the early stages of germination and seedling growth. Exogenous NO2-OA treatment (100 µM, 24 h) of Brassica seeds resulted in significantly increased ●NO level and induced germination capacity compared to untreated seeds. The results of in vitro approaches (4-Amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM) fluorescence, ●NO -sensitive electrode) supported the ●NO liberating capacity of NO2-OA. We observed for the first time that Brassica seeds and seedlings contain free NO2-OA which may be involved in germination as an ●NO donor as suggested both by the results of exogenous NO2-OA treatment of seeds and in vitro approaches. Due to their high NO2- OA content, Brassica sprouts can be considered as a good source of dietary NO2-OA intake.

Pigments of the Moss Paraleucobryum longifolium: Isolation and Structure Elucidation of Prenyl-Substituted 8,8'-Linked 9,10-Phenanthrenequinone Dimers.

In a search for new secondary metabolites from mosses, leucobryns A-E, axially chiral 9,10-phenanthrenequinone dimers, were isolated from Paraleucobryum longifolium (1-5), together with diosmetin triglycoside. Leucobryns B (2) and C (3) were proved to be homodimeric atropodiastereomers containing both axial and central chirality elements, while leucobryns D (4) and E (5) were found to be heterodimeric atropodiastereomers containing central chirality in only one of the two monomeric units. Axial chirality of the compounds was determined by ECD measurements and sTDA ECD calculations, while the central chirality elements were assigned by TDDFT-SOR calculations. Leucobryns represent the first 9,10-phenanthrenequinone dimers, the monomers of which are linked through their C-8 atoms. Leucobryns B-E contain an uncommon C10 monoterpenoid side chain, in which isoprenoid units are joined by 3,4 linkages. Leucobryns A and B exhibited weak antiproliferative activity against several human cancer cell lines.

Antiproliferative and Antimicrobial Activities of Selected Bryophytes.

One-hundred and sixty-eight aqueous and organic extracts of 42 selected bryophyte species were screened in vitro for antiproliferative activity on a panel of human gynecological cancer cell lines containing HeLa (cervix epithelial adenocarcinoma), A2780 (ovarian carcinoma), and T47D (invasive ductal breast carcinoma) cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and for antibacterial activity on 11 strains using the disc-diffusion method. A total of 99 extracts derived from 41 species exerted ≥25% inhibition of proliferation of at least one of the cancer cell lines at 10 µg/mL. In the cases of Brachythecium rutabulum, Encalypta streptocarpa, Climacium dendroides, Neckera besseri, Pleurozium schreberi, and Pseudoleskeella nervosa, more than one extract was active in the antiproliferative assay, whereas the highest activity was observed in the case of Paraleucobryum longifolium. From the tested families, Brachytheciaceae and Amblystegiaceae provided the highest number of antiproliferative extracts. Only 19 samples of 15 taxa showed moderate antibacterial activity, including the most active Plagiomnium cuspidatum, being active on 8 tested strains. Methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus were the most susceptible to the assayed species. This is the first report on the bioactivities of these 14 species.