Search results for "Rite"
showing 10 items of 2726 documents
Oxidized respiratory molecules induced in vivo by nitrite in Pontodrilus littoralis (oligochaeta)
1992
Abstract 1. The in vivo effect of nitrite has been investigated in Pontodrilus littoralis. 2. Exposure of the animals at nitrite concentrations (0.05–0.1%) produced methaemoglobin and hemichromes. 3. Disappearance of oxidized forms was obtained when normal rearing conditions were restored. 4. Longer exposure to higher nitrite concentrations produced irreversible oxidized forms.
Effects of triterpenes on the immune system.
2010
Ethnopharmacological relevance: Triterpenes, which comprise a broad chemical group of active principles, are implicated in the mechanisms of action and pharmacological effects of many medicinal plants used in folk medicine against diseases in which the immune system is implicated. They have been described as anti-inflammatory, antiviral, antimicrobial, and antitumoral agents, as well as being immunomodulator compounds. Several of them are implicated in the resolution of immune diseases, although their effects have not always been clearly correlated. Aim of the review: The aim of this review is to compile relevant data on the mechanisms of action of triterpenes isolated from active ethnomedi…
A review of natural and modified betulinic, ursolic and echinocystic acid derivatives as potential antitumor and anti-HIV agents.
2003
The aim of this review is to update current knowledge on the betulinic, ursolic and echinocystic acids and their natural and semisynthetic analogs, focussing on their cytotoxic and anti-HIV activities. Then, the last results of the authors' team on unusual semisynthetic derivatives of these triterpenoids will be presented in order to establish structure/activity relationships.
New ursolic and betulinic derivatives as potential cytotoxic agents.
2003
Fifteen new ursolic and betulinic triterpenoids, bearing various functionalities at C-3 and C-28 were synthesized as potential cytotoxic agents. All compounds were obtained by a hemisynthetic route via ursolic and betulinic acids. Preliminary screening of these compounds on human HT 29 colon cancer cells revealed inhibitory activity for three of them. Beta-D-Glucopyranosyl-3beta-hydroxyurs-12(13)-en-28-oate 1c, 3beta-3-(3-pyridyl)-prop-2-enoyloxyurs-12(13)-en-28-oic acid 1i and the potassium salt of 3beta-cinnamoyloxylup-20(29)-en-28-oic acid 2d demonstrated cytotoxic activity in the micromolar range: 8.0, 45.0 and 8.0 microM, respectively.
Triterpenoid Saponins From the Stem Bark of Pentaclethra eetveldeana
2019
Two previously undescribed triterpenoid saponins together with 4 known ones were isolated from the stem bark of Pentaclethra eetveldeana De Wild. & Th. Dur. Their structures were elucidated by spectroscopic methods including 1D and 2D NMR experiments in combination with mass spectrometry as 3- O-β-D-glucopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosyloleanolic acid and 3- O-β-D-glucopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosylhederagenin.
Triterpenoid Saponins From the Root Bark of Haplocoelum congolanum
2019
Two undescribed triterpenoid saponins together with 5 known ones were isolated from the root bark of Haplocoelum congolanum Hauman. Their structures were elucidated by spectroscopic methods including one-dimensional and two-dimensional nuclear magnetic resonance experiments in combination with mass spectrometry as 3- O-(4- O-[3-hydroxy-3-methylglutaryl])-α-l-arabinopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-[β-d-glucopyranosyl-(1→4)]-α-l-arabinopyranosyloleanolic acid and 3- O-α-l-arabinofuranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-[β-d-glucopyranosyl-(1→4)]-α-l-arabinopyranosyloleanolic acid.
Effects of plant alkylphenols on cytokine production, tyrosine nitration and inflammatory damage in the efferent phase of contact hypersensitivity
2007
Background and purpose: The phenolic compounds isoprenylhydroquinone glucoside (IHG), 3,5-dicaffeoylquinic acid (DCA), and its methyl ester (DCE) have previously been shown to inhibit both contact hypersensitivity (CHS) and peroxynitrite reactivity. The present work seeks to establish a relationship between the anti-inflammatory effect and the release of cytokines and tyrosine nitration in skin. Experimental approach: Murine CHS was developed by means of sensitization and challenge with dinitrofluorobenzene (DNFB) or oxazolone. Ear swelling was measured 24 and 96 h after challenge. Interleukin (IL)-1b, IL-4, and tumour necrosis factor (TNF)-a were measured by ELISA; and the expression of in…
Cycloartane-type saponins from astragalus tmoleus var. tmoleus
2016
Five known cycloartane-type glycosides were isolated from the roots of A. tmoleus Boiss. var. tmoleus. The identification of these compounds was mainly achieved by 1D and 2D NMR spectroscopic techniques and FABMS. The results of our studies confirm that triterpene saponins with the cycloartane-type skeleton might be chemotaxonomically significant for the genus Astragalus.
Triterpene Saponins from the Roots of Achyranthes bidentata
2001
Three saponins, oleanolic acid-28- O -s-D-glucopyranoside (1), chikusetsusaponin V (2), and 3- O -s-D-glucopyranosyl-oleanolic acid-28- O -s-D-glucopyranoside (3) were isolated from the roots of Achyranthes bidentata Blume (Amaranthaceae). No activity was shown in the granulocyte phagocytosis test nor in the test of the potentiation of the cytotoxicity of cisplatin in human colon cancer cells. This is the first report of compounds 1, 2 and 3 isolated from Achyranthes species. Furthermore, the NMR data of 2 completed the partially published data.
Triterpene Saponins from Wisteria floribunda “macrobotrys” and “rosea”
2017
Five oleanane-type saponins were isolated from two cultivars of Wisteria floribunda (Willd.) DC. (Fabaceae): From the roots of Wisteria floribunda “macrobotrys”, one new oleanane derivative elucidated as 3- O-β-D-xylopyranosyl-(1→2)-β-D-glucuronopyranosyl-22- O-acetyl-3p,22p,24-trihydroxyolean-12-en-30-oic acid, and two known glycosides, and from the roots of Wisteria floribunda “rosea”, two known ones. Their structures were elucidated by a detailed 600 MHz NMR analysis including 1D and 2D NMR (1H, 13C, COSY, TOCSY, ROESY, HSQC, HMBC) experiments and mass spectrometry. Chemotaxonomic conclusions were proposed.