lignans and catechol

Benzo[kl]xanthene lignans, promising bioactive polyphenols obtained by biomimetic oxidative coupling of caffeic acid derivatives, react efficiently with peroxyl radicals in both polar and non-polar solvents, thanks to the simultaneous presence of guaiacol-like and catechol-like OH-groups.

Topics: Caffeic Acids; Catechols; Free Radicals; Guaiacol; Lignans; Peroxides; Xanthenes

The expression of cell adhesion molecules (CAMs) has been implicated as one of the most important causes of the development of inflammatory diseases such as atherosclerosis, and, it is speculated that the prevention of it is an effective approach to the control of atherosclerosis. In the present study, we investigated the effect of sesame lignans on the expression of CAMs in human umbilical vein endothelial cells (HUVECs) induced by tumor necrosis factor-alpha (TNF-alpha). Based on cell-ELISA analysis, we found that sesaminol-6-catechol downregulated the TNF-alpha-induced expression of CAMs in a dose-dependent manner. Moreover, these inhibitory effects were caused to be drastically exerted by downregulating the CAM proteins in TNF-alpha-activated HUVECs at transcriptional level. This suggests, that sesaminol-6-catehcol suppresses the expression of CAMs, and may be an active component of sesame lignans.

Topics: Animals; Anti-Inflammatory Agents; Cardiovascular System; Catechols; Cell Adhesion Molecules; Cell Line; Endothelial Cells; Gene Expression Regulation; Humans; Lignans; Sesamum; Transcription, Genetic; Tumor Necrosis Factor-alpha

We report here the first selective de-O-methylation of a large panel of guaiacyl lignans to the corresponding catechol derivatives by using IBX as primary oxidant under green conditions (dimethyl carbonate-H(2)O solvent) through an in situ reduction procedure. The influence of the catechol moiety on the cytotoxicity and genotoxicity of new lignan derivatives has been investigated. The results obtained indicated that the presence of the catechol moiety sharply enhances the clastogenic potential (e.g. induction of chromosomal aberrations), the cytotoxicity and the modulation of cell cycle progression with respect to the parent compounds. Thus, despite the in vitro antioxidant activity usually described for catechol derivatives, our results show for the first time the generation of a clastogenic potential, highly indicative of a long-term genetic and cancer risk.

Topics: Animals; Catechols; Cell Division; Cell Line; Cell Proliferation; Cricetinae; Iodobenzenes; Iodobenzoates; Lignans; Methylation; Mutagenicity Tests; Oxidation-Reduction

Sesamin, the major sesame oil lignan, is recognized for its health-promoting effects, including the lowering of cholesterol and elevation of gamma-tocopherol in rats and humans. However, little is known about the absorption and metabolism of sesamin in humans. In this study, 6 healthy volunteers took a single dose of sesame oil (508 micromol sesamin) and their urine was collected for four 12-h periods. The urine samples were treated with beta-glucuronidase/sulphatase and extracted with chloroform. The major urinary sesamin metabolite in the chloroform extract was collected using HPLC diode array detector and characterized as (1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo-[3,3,0]octane using NMR and mass spectroscopy. A quantitative (1)H-NMR technique, based on the methylenedioxyphenyl protons signal (delta 5.91), was used for the quantification of the metabolite in the chloroform extracts of urine. The excretion of the sesamin catechol metabolite ranged from 22.2 to 38.6% (mean +/- SD, 29.3 +/- 5.6) of the ingested dose and happened mainly in the 1st 12 h after ingestion.

Topics: Adult; Catechols; Chromatography, High Pressure Liquid; Dioxoles; Dose-Response Relationship, Drug; Female; Humans; Lignans; Magnetic Resonance Spectroscopy; Male; Mass Spectrometry; Octanes; Pilot Projects; Sesame Oil; Time Factors