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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The Flavonols Quercetin, Myricetin, Kaempferol, and Galangin Inhibit the Net Oxygen Consumption by Immune Complex-Stimulated Human and Rabbit Neutrophils

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Author(s):
Figueiredo-Rinhel, Andrea S. G. [1] ; Santos, Everton O. L. [1] ; Kabeya, Luciana M. [1] ; Azzolini, Ana Elisa C. S. [1] ; Simoes-Ambrosio, Livia M. C. [1] ; Lucisano-Valim, Yara M. [1]
Total Authors: 6
Affiliation:
[1] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Quim & Fis, BR-14040903 Ribeirao Preto, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: ZEITSCHRIFT FUR NATURFORSCHUNG SECTION C-A JOURNAL OF BIOSCIENCES; v. 69, n. 7-8, p. 346-356, JUL-AUG 2014.
Web of Science Citations: 7
Abstract

Stimulated human neutrophils exhibit increased net oxygen consumption (NOC) due to the conversion of O-2 into the superoxide anion by the NADPH oxidase enzymatic complex during the respiratory burst. In several inflammatory diseases, overproduction of these oxidants causes tissue damage. The present study aims to: (a) optimize the experimental conditions used to measure the NOC in serum-opsonized zymosan (OZ)- and insoluble immune complex (i-IC)-stimulated human and rabbit neutrophils; and (b) compare the effect of four flavonols (quercetin, myricetin, kaempferol, and galangin) on this activity. We used a Clark-type oxygen electrode to measure the NOC of stimulated neutrophils. Eliciting the neutrophil respiratory burst with OZ and i-IC yielded similar maximum O-2 uptake levels within the same species, but the human neutrophil NOC was almost four times higher than the rabbit neutrophil NOC. The optimal experimental conditions established for both cell types were 4 . 10(6) neutrophils mL(-1), 2 mg mL(-1) OZ, and 240 mu g mL(-1) i-IC. Upon stimulation with OZ or i-IC, the tested flavonols reduced the human and rabbit neutrophil NOC in the same order of potency quercetin and galangin were the most and the least potent, respectively. These compounds were around four times more effective in inhibiting the rabbit as compared to the human neutrophil NOC, respectively. The four flavonols were not toxic to human or rabbit neutrophils. The experimental conditions used are suitable for both the determination of human and rabbit neutrophil NOC and for the assessment of the modulatory effects of natural compounds on these activities. The relationship between the level of NOC and the inhibitory potency of the flavonols suggests that rabbit neutrophils can be useful experimental models to predict the effect of drugs on immune complex-stimulated human neutrophils. (AU)

FAPESP's process: 07/00840-8 - Study of the mechanism of action of coumarin derivatives on the myeloperoxidase activity: investigation about metabolization of these compounds to phenoxyl free radicals, implications on the oxidative stress and modulation of leukocyte functions
Grantee:Luciana Mariko Kabeya
Support Opportunities: Scholarships in Brazil - Post-Doctoral