Phenolic compound

Eleven allelochemicals (ferulic acid, cinnamic acid, 4-hydroxybenzoic acid, hydroxycinnamic acid, methyl propionate, oxalic acid, methylmalonic acid, p-anisic acid, butyric acid, 3-hydroxybutyric acid, and azulene) were identified in the exudate of Cistus ladanifer L. We studied the effect of each on germination, cotyledon emergence, root length, and cotyledon length of Rumex crispus. Three groups were distinguished with respect to phytotoxic activity: compounds with low activity (ferulic acid, 4-hydroxybenzoic acid, oxalic acid, methylmalonic acid, p-anisic acid, hydroxybutyric acid, and azulene), with intermediate activity (cinnamic acid and hydroxycinnamic acid), and with high activity (methyl propionate and butyric acid). The effect of the interaction of the compounds was studied. When acting conjointly, all combinations tested produced a more negative effect on both germination and seedling growth than when acting alone. The interaction affected cotyledon emergence and root length more negatively than germination and cotyledon length. When hydroxycinnamic acid and cinnamic acid were added to these mixtures there was an enhancement in the phytotoxic activity, accentuating the effect of the other allelochemicals.

ABSTRACT The catalytic activity of copper-based metal organic framework compound (Cu-MOF) in the wet hydrogen peroxide catalytic oxidation (WHPCO), using p-coumaric acid as model phenolic compound, have been studied and compared with that of a copper-based pillared clays (Cu-PILC). Cu-MOF shows a high activity, but a structural and morphological change is observed during the reaction, even if the activity of the reused catalyst is higher in consecutive cycles with respect to that of the fresh sample.

Phenolic compounds are major constituents of red wines and impact on certain wine-quality parameters. This study has aimed to increase the knowledge base on the phenolic composition of South African red wines by HPLC quan-tification of 39 individual phenols and 2 polymeric, phenolic groups in 260 South African wines of the cultivars Pinotage, Shiraz and Cabernet Sauvignon. Statistical analysis of the collected data revealed significant cultivar dif-ferences in the levels of many of the analysed compounds, as well as in the ratios in which specific anthocyanins are found in the wines. These data may be helpful in the cultivar authentication of wines of these cultivars. Discriminant analysis of the data showed statistically significant separations of cultivars, based on their polyphenol composition, and also how the use of data from a specific wine-producing area or vintage improved the possibilities for success-ful authentication. The data were collected from both pure cultivar wines...

Natural flavonoids are currently receiving much attention because of their estrogenic and antiestrogenic properties. Six isoflavones (isoprunetin, isoprunetin 7-O-β-d-glucopyranoside, isoprunetin 4′,7-di-O-β-d-glucopyranoside, genistein, genistein 7-O-β-d-glucopyranoside, daidzein), four flavones (luteolin, luteolin 7-O-β-d-glucopyranoside, luteolin 4′-O-β-d-glucopyranoside, licoflavone C), isolated from Genista morisii and G. ephedroides (two Leguminosae plants of the Mediterranean area) together with two structurally related pterocarpans, bitucarpin A and erybraedyn C, isolated from Bituminaria bituminosa (Leguminosae), were tested for the antagonist activity by a yeast based estrogen receptor assay (Saccharomyces cerevisiae RMY326 ER-ERE). Most compounds inhibited the estradiol-induced transcriptional activity in a concentration dependent manner. In particular, for the flavone luteolin 77% inhibition of the induced β-galactosidase activity was observed. Interestingly, licoflavone C exhibited a dose-dependent antagonistic activity at concentrations up to 10−4 m, but stimulated β-galactosidase expression at higher concentrations resulting in a U-shaped-like dose-response curve. Copyright © 2007 John Wiley & Sons, Ltd.

Micropropagation of Origanum vulgare L. by shoot buds, as a potential model system for studying carbon skeleton diversion from growth to secondary metabolism as adaptive response to nutrient deficiency, has been performed. In addition, the antioxidant phenolic compounds, produced by shoots under nutritional stress or in response to exogenously added proline, have been studied. Caffeic acid, rosmarinic acid, and lithospermic acid B have been isolated in oregano shoot cultures by reversed-phase high-performance liquid chromatography, and their structures have been elucidated by tandem mass spectrometry. Both nutritional stress, which in turn causes a moderate increase of constitutive free proline, and exogenous proline affect growth and antioxidant phenolic content of oregano shoots, compared to control.The role of proline, and the associated redox cycle, as a form of metabolic signaling based on a transfer of redox potential amongst interacting cell pathways, which in turn elicit phenolic metabolism via stimulated carbon flux through oxidative pentose phosphate pathway, is discussed. Furthermore, the potential use of oregano tissue and callus cultures as a new strategy to enable the production of useful secondary metabolites on a commercial scale is also discussed.

Antioxidant capacity and antimicrobial activities ofLepista nuda (Bull.) Cooke extracts obtained with ethanol were investigated. Four complementary test systems, namely DPPH free radical scavenging, β-carotene/linoleic acid systems, total phenolic compounds and total flavonoid concentration, have been used. Linoleic, acid inhibition values ofL. nuda ethanolic extract, BHA and α-to copherol standards were found to be 84.3% 98.9% and 99.2% respectively in the concentration of 160μg/ml. Total flavonoid amount was 8.21 ± 0.56 μg mg−1 quercetin equivalent while the phenolic compound amount was 48.01 ± 0.29 μg mg−1 pyrocatechol equivalent in the extract. The antimicrobial activity ofL. nuda extract was testedin vitro by using the agar-well diffusion method. TheL. nuda extract showed antibacterial activity againstMicrococcus flavus, Micrococcus luteus, Bacillus cereus, Yersinia enterocolitica, Staphylococcus aureus, Salmonella enteritidis andEscherichia coli. TheL. nuda extract did not exhibit antican didal activity againstCandida albicans. The extracts could be suitable as antimicrobial and antioxidativeagents in the food industry.