Effect of Royal Jelly on Formalin Induced-Inflammation in Rat Hind Paw

Background: Royal Jelly (RJ), a food item secreted by worker honeybees, is a mixture that contains protein, glucose, lipid, vitamins, and minerals; it is widely used as a commercial medical product. Previous studies have shown that RJ has a number of physiological effects, such as anti-inflammatory, antitumor, antiallergic and antioxidant activities. Objectives: In the present study, the anti-inflammatory properties of RJ were investigated in formalin-induced rat paw edema. Materials and Methods: In this study, 30 male Wistar albino rats were divided into five equal groups (n = 6) as follows: test groups received different doses (25, 50 and 100 mg/kg, ip) of RJ and a negative control group received normal saline (5 mL/kg) and a positive control group received aspirin (300 mg/kg, i.p). Edema was induced on the right hind paw of the rat by a subplantar injection of 100 μL of formalin (2.5%) after 30 minutes. Paw edema was measured in the rats received the drugs, saline and aspirin before and after the formalin injection during 5 hours, using a plethysmometer. Results: The results showed that RJ has a dose-dependent anti-inflammatory effect and the highest anti-inflammatory effect was observed in the doses of 50 and 100 mg/kg. Conclusions: Royal jelly has potent anti-inflammatory effects compared to aspirin and it could be used in the treatment of inflammation. However, further studies are required to determine the active components in RJ responsible for this effect and its mechanism of action