Chalcones from Myracrodruon urundeuva are efficacious in guinea pig ovalbumin-induced allergic conjunctivitis

The objective of the study was to verify the effects of dimeric chalcones (urundeuvines A, B, and C) from Myracrodruon urundeuva Allemao, Anacardiaceae (a Brazilian anti-inflammatory species), on an allergic conjunctivitis model. Male guinea-pigs were sensitized with two intraperitoneal injections of ovalbumin (10 mu g dissolved in 0.5 mL saline and emulsified in 0.5 mL Freund's adjuvant), at days 0 and 7. At day 24, the animals were submitted to an ocular instillation (right eyes) with ovalbumin. At the next day, the animals were treated with chalcones (0.5 mg, three times a day for 7 days), 0.1% fluormetalone acetate (0.05 mg, as the reference drug) or saline. After anesthesia of the animals, enucleations of their corneas and conjunctivas were carried out for morphometric and histological analyses, at days 1, 3 and 7. Their radical scavenging activity and action on myeloperoxidase were also determined. We demonstrated that chalcones from M. urundeuva stem barks presented anti-inflammatory and antioxidant effects, and drastically inhibited the MPO activity, pointing them as candidates for the treatment of allergic conjunctivitis and other inflammatory conditions.