Effects of flavonoids on interleukin-1β.

L Villaescusa1, C Zaragozá1, C Mantecón1, T Martín1, J Monserrat2, F Zaragozá1, M Álvarez de Mon2. 1Universidad de Alcalá, Pharmacolgy 28871, Spain, 2Universidad de Alcalá, Medicine 28871, Spain

Background: Flavonoids exhibit both phlebotonic and anti-inflammatory properties than could be correlated. However, there may be differences between the effects of the heterosides and those of the corresponding genins.

Aims: to compare the effects of two glycosides (naringin and rutin) with those of their genins (naringenin and quercetin) on whole blood production of IL-1β.

Methods: Whole blood was collected into 3.8% (wt/vol) sodium citrate from healthy adult donors (n = 40). First, blood preserved from light was incubated with the flavonoids and the antraquinone derivative rhein was used as a positive control for 30 min at 37°C in a bath with constant stirring. LPS (10mg/ml) is then added and samples incubated at 37°C 6h in the dark; afterwards samples were centrifuged at 4000 rpm for 10 min, the supernatant collected and homogenized samples were tested simultaneously in duplicate. IL-1 β was measured with specific immunoassay techniques (the detection limits was 10pg/ml). All samples were tested simultaneously in duplicate at appropriate dilutions.

Results: LPS induced the release of IL-1β as compared to control blood. Rhein-induced inhibition of IL-1β release (positive control) was 41.0 ± 7.3%. Inhibition induced at 0.5, 1 and 2 mM quercetin averaged 35.9 ± 2, 61.1 ± 2.9 and 87.1 ± 3.8, with naringenin 22,8 ± 5.4, 57.1 ± 4,5 and 73.6 ± 5.8 and with naringin 27.1 ± 6.4, 34.2 ± 7.9 and 44.2 ± 7.5, respectively. However, rutin did not modify the relase of IL-1β.

Conclusión: Inhibition of IL-1β release caused by these drugs justifies its anti-inflammatory activity.