Effects of Scutellariae radix extract and its components (baicalein, baicalin, and wogonin) on the experimental elevation of aqueous flare in pigmented rabbits

Purpose: To evaluate the possible inhibitory effects of hot water extract o f Scutellariae radix and its major components (baicalein, baicalin, and wog onin) on experimental elevation of aqueous flare in pigmented rabbits. Methods: To produce aqueous flare elevation in rabbits, prostaglandin E-2 ( PGE(2)), 25 mug/mL, was applied to the cornea with the use of a glass cylin der, or lipopolysaccharides (LPS), 0.5 mug/kg, were injected into an ear ve in. Animals were pretreated by the oral administration of 150 g/day of food containing 0.029%, 0.07%, or 0.2% (w/w) extract of Scutellariae radix for 5 days, or by intravenous injection of baicalein, baicalin, or wogonin, 60 mug/kg or 600 mug/kg, 30 minutes before experimental uveitis was induced. A queous flare was measured with a laser flare-cell meter. Aqueous flare inte nsity was expressed as the area under the curve (AUC) in arbitrary units. Results: The AUC of PGE(2)- and LPS-induced aqueous flare elevation was 1,3 43 and 5,066 arbitrary units, respectively. Pretreatment by oral administra tion of 0.07% or 0.2% extract of Scutellariae radix did not inhibit PGE(2)- induced aqueous flare elevation (AUC: 1,252 and 1,210, respectively), but i t did inhibit LPS-induced aqueous flare elevation (AUC: 2,248 and 1,973, re spectively). Pretreatment by intravenous injection of 600 mug/kg of baicale in, baicalin, or wogonin inhibited LPS-induced aqueous flare elevation (AUC : 2,289, 2,163, and 1,509, respectively). Pretreatment with 60 mug/kg of wo gonin also inhibited LPS-induced aqueous flare elevation (AUC: 1,980). Conclusion: Hot water extract of Scutellariae radix may have an inhibitory effect on experimental anterior uveitis induced by LPS in pigmented rabbits . (C) 2001 Japanese Ophthalmological Society.