Yimam et al. flavonoids were detected using a UV detector at 275 nm and identified based on retention time by comparison with known flavonoid standards. 158 Animals Purpose bred male CD-1 mice (7–9 weeks), weighing 25–30 g and male Wistar rats weighing 145–160 g were purchased from US Department of Agriculture (USDA) approved laboratory animal vendor (Charles River Laboratories, Inc., Wilmington, MA). Animals were acclimated upon arrival for a week before being assigned ran- domly to their respective groups. Mice (5/cage) and rats (3/cage) were housed in a polypropylene cage and individually identified by numbers on their tail. Each cage was covered with wire bar lid and filtered top (Allentown, NJ). Individual cage was identified with a cage card indicating project number, test article, dose level, group, and an animal number. The Harlan T7087 soft cob beddings were used and changed at least twice weekly. Animals were provided with fresh water and rodent chow diet # T2018 (Harlan Teklad, 370W, Kent, WA) ad libitum and were housed in a temper- ature controlled room (22.2◦C) on a 12 hr light-dark cycle. All animal experiments were conducted according to institutional guidelines congruent with guide for the care and use of laboratory animals. Carrageenan-Induced Inflammation Local inflammation was induced by intraplantar injection of carrageenan λ (Sigma, St. Louis, MO; 100 µ l of 1% [w/v] in saline) into the plantar surface of right hind paw of sedated rat (with 2.5% isoflurane) at time 0 (T = 0) (Gamache et al., 1986; Guay, Bateman, Gordon, Mancini, & Riendeau, 2004; Huang, Lee, & Yang, 2006; dos Santos, Almeida, Lopes, & de Souza, 2006). Rats were placed under an inverted plexiglass cages on a wire mesh rack and allowed to acclimate for 20–30 min before each measurement was taken. Allodynia was evaluated by measuring responsive- ness to a semiflexible tip applied through the mesh floor perpendicular to the central plantar surface of the right hind paw. The tip was gradually applied with sufficient force to cause slight buckling of the filament against the paw. A positive response to the applied tactile pressure, noted by sharp withdrawal of the paw, was recorded automatically by an electronic Von Frey Anesthesiometer (2390 series Electrovon- frey, IITC, Woodland Hills, CA) (Vivancos, et al., 2003). Mechanical allodynia was evaluated before carrageenan inoculation, and thereafter 1 hr, 2 hr, 4 hr, and 6 hr. Paw edema was measured with the use of Plethysmometer (IITC, Woodland Hills, CA; Model 520) at time 0 (before carrageenan), 1 hr, 2 hr, 4 hr, and 6 hr af- ter carrageenan injection. Animals (N = 12 per group) were orally gavaged with a positive control ibuprofen (Sigma, St. Louis, MO; lot # 037K1345) (150 mg/kg); test articles: UP446 (Unigen, Lacey WA; lot #UV07080) (150 mg/kg), and vehicle control (propylene glycol) 30 min before carrageenan induction. Nociceptive Behavior Elicited by Intraplantar Injection of Formalin in Mice Mice (N = 12 per group) were habituated under an inverted Plexiglas observation chamber for 30 min to allow them to acclimatize to their surroundings. Animals were treated orally with 100 mg/kg of UP446, 100 mg/kg of ibuprofen, or vehicle control (propylene glycol) 30 min before intraplantar injection of formalin (20 µ l of 2.5% solution) into the right hind paw of restrained mice using Hamilton syringe