Objective: Though the initial etiologies of arthritis are multifactorial, clinically, patients share the prime complaints of the disease, pain. Here the authors assessed the analgesic and anti-inflammatory effects of UP1304, a composite that contains a standardized blend of extracts from the rhizome of Curcuma longa and the root bark of Morus alba, on rats with carrageenan-induced paw edema.
Methods: A plant library was screened for bradykinin receptor antagonists. In vivo, the anti-inflammatory and analgesic effects of the standardized composite, UP1304, were evaluated in rats with carrageenan-induced paw edema using oral dose ranges of 100-400 mg/kg. Ibuprofen, at a dose of 200 mg/kg, was used as a reference compound. In vitro, cyclooxygenase (COX) and lipoxygenase (LOX) inhibition assays were performed to evaluate the degree of inflammation.
Results: Statistically significant improvements in pain resistance and paw edema suppression were observed in animals treated with UP1304, when compared to vehicle-treated rats. Results from the highest dose of UP1304 (400 mg/kg) were similar to those achieved by ibuprofen treatment at 200 mg/kg. In vitro, UP1304 showed dose-dependent inhibition of the enzymatic activities of COX and LOX. A half-maximal inhibitory concentration of 9.6 μg/mL for bradykinin B1 inhibition was calculated for the organic extract of C. longa. Curcumin showed Ki values of 2.73 and 58 μg/mL for bradykinin receptors B1 and B2, respectively.
Conclusion: Data presented here suggest that UP1304, analgesic and anti-inflammatory agent of botanical origin, acted as a bradykinin receptor B1 and B2 antagonist, and inhibited COX and LOX enzyme activities. This compound should be considered for the management of symptoms associated with arthritis.