Screening of flavonoid "quercetin" from the rhizome of Smilax china Linn. for anti-psoriatic activity.

OBJECTIVE

To assess anti-psoriatic activity of the methanol extract and the isolated flavonoid quercetin from the rhizome of Smilax china (S. china) Linn.

METHODS

Mouse tail test was used for the evaluation of anti-psoriatic activity. Methanol extract (100 and 200 mg/kg b.w.) and isolated flavonoid quercetin (25 and 50 mg/kg b.w.) were tested in Swiss albino mice. Parameters studied in the mouse tail test were changes in epidermal thickness and percentage orthokeratotic values. The anti-inflammatory role of the methanol extract and isolated flavonoid quercetin was evaluated using carrageenan-induced pleurisy in rats. In vitro antiproliferant assay on HaCaT cell lines was also carried out.

RESULTS

The isolated flavonoid quercetin from the rhizome of S. china produced significant orthokeratosis (P<0.01) in the mouse tail test. In epidermal thickness, a significant reduction with respect to control was observed in groups treated with retinoic acid and isolated flavonoid quercetin. The methanol extract (200 mg/kg) and isolated flavonoid quercetin (50 mg/kg) showed anti-inflammatory effect in terms of significant inhibition (P<0.001) in leukocyte migration. Maximum antiproliferant activity was shown by isolated flavonoid quercetin (IC50, 62.42±10.20 µg/mL).

CONCLUSIONS

From the above data, the flavonoid quercetin shows significant orthokeratosis, anti-inflammatory and maximum antiproliferant activities. To our knowledge, this is the first report on the anti-psoriatic effect of the flavonoid quercetin which is promising for further investigations to prove its anti-psoriatic activity.