Relaxant Effects of Quercetin and Rutin on Human Isolated Bronchus

Increasing epidemiological evidence supports the view, that quercetin has protective roles in a multitude of disease states in human who have a high intake of polyphenols. To investigate the ability of quercetin and its rutinoside, rutin, to modulate the relaxation of human airways smooth muscle and to determine the mechanism (s) of such relaxation, isolated human bronchus rings were suspended in individual organ baths, precontracted with acetylcholine or with histamine and the relaxing effects of quercetin and rutin were determined by measurement of isometric tension. Quercetin induced concentration-dependent relaxant responses on acetylcholine or histamine precontracted human bronchial rings and with almost equal effectiveness. In terms of potency (pD2) and efficacy (Emax), quercetin is more potent than rutin on relaxant responses of human bronchus. K+ and Ca2+ concentration-dependent contraction curves were inhibited after incubation with increasing concentrations of quercetin. Quercetin potentiated in a concentration-dependent manner the relaxant effects of isoprenaline or sodium nitroprusside. Rutin had no effect on K+-induced contraction and on relaxant activity of isoprenaline or sodium nitroprusside. Our results suggest that the bronchodilator effects of quercetin are modulated by an increase in cyclic nucleotide levels as well as an alteration in availability of Ca2+ to the contractile machinery.

Antihymolytic and Antioxidant Effects of Medicinal Plant Capparis spinosa L.

Capparis spinosa L. is a traditionally used plant in Algerian folk medicine to treat asthma, rheumatism and other free radicals related disorders such inflammatory. The present study was designated to study the antioxidant activity of aerial and root parts of Capparis spinosa L.. Total polyphenol content was determined, after extraction with solvents in five subfractions; methanol （CE）, Hexan （HE） chloroform （CHE）, ethyl acetate （EAE） and aqueous extracts （AE）, employing the ＂Prussian blue assay＂. The results showed that EAE containing the highest concentration of phenolic compounds and Flavonoids followed by those of CHE of aerial and root parts, repectively. The antioxidant protective effects of extracts were determined by measuring the erythrocyte membrane resistance to free radical-induced. The results demonstrated that all the extracts exhibited a protective effect against t-BHP induced oxidative damages in human erythrocytes, the most potents wer CEs and CHEs with 86.55%, 85.81%, 74.59%, and 68.70%, for aerial and root parts, respectively, which were more effective than used standards： Quercetin （65.46%） and rutin （59.62%）. In order to more clarify the previous antioxidants activity of the extracts through other mechanisms, the iron chelating ability assays were realized. The results showed that the iron chelating ability of Aerial and root extracts were very considerable; the CE showed an excellent chelating with ICs0 of 0.197 ± 0.031 μM/quercetin equivalent, higher than that used standard EDTA, with approximately 0.34 folds. These results show that Capparis spinosa L. extracts have strong anti-oxidant effects and may have some clinical benefits.

Inhibitory Activity on Xanthine Oxidase and Antioxidant Properties of <i>Teucrium polium</i>

The antioxidative activities of subfractions;methanol (CE), chloroform (CHE) and ethyl acetate (EAE) of Teucrium polium extracts (TPE) were investigated. HPLC analysis of the plant revealed the existence of procyanidins B1 and B2, gallic acid, catechin and epicatechin. All the extracts showed inhibitory properties on xanthine oxidase, with IC50 ranging from 0.80 ± 0.07 to 11.76 ± 0.50 μM/quercetin equivalent. In the cellular system, all the extracts showed a protec-tive effect greater than those of quercetin, rutin and gallic acid against t-BHP induced oxidative damages in human erythrocytes. These results were clearly confirmed by a modified thiobarbituric acid-reactive species (TBARS), and β-carotene/linoleic acid assay which demonstrated that CHE possess an inhibition ratio of the linoleic acid oxidation (83.11%) close to that of BHT (96.77%). In addition, the results showed that the extracts possess a potent DPPH radical scavenging activity and gave a reduction power greater than rutin, quercetin, gallic acid and ascorbic acid in FRAP assay. These results show that Teucrium polium extracts have strong antioxidant effects and may have some clinical benefits.