The effects of Ocimum basilicum ethanol extract on carrageenan induced paw inflammation in rats

Background: Traditionally, Ocimum basilicum has been used for its anti-inflammatory activity. Here, the effect of O. basilicum ethanol extract was evaluated on carrageenan induced paw edema in male Wistar rats. Methods: O. basilicum ethanol extract was achieved through maceration procedure. Next, the paw inflammation was induced with 1% carrageenan, subcutaneous, to all groups after 1h of the intrapritoneal injection of O. basillicum extracts (0, 2.5, 5 and 10mg/kg; respectively). The paw thickness was measured at hourly intervals for 4h. Finally, histological examination and Myeloperoxidase (MPO) activity was assessed in the inflamed paw at the 4thh. Moreover, total phenolic and flavonoid content of the extract was determined. Besides, different in vitro antioxidant activities were detected by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, nitric oxide radical inhibition and reducing power methods. Results: The extract diminished paw inflammation as indexed by reduction paw thickness (p<0.001) as well as MPO activity (p<0.001), which was associated with a marked decrease in tissue edema and leukocyte infiltration. In addition, values for the total phenolic and flavonoids were calculated as 266 mg gallic acid equivalent and 65 mg quercetin equivalent per 100g of O. basilicum fresh plant material. Furthermore, the RC50 values for DPPH and nitric oxide antioxidant activity of the extract was determined as 118µg/mL and 929.7µg/ml. Conclusions: Ethanol extract of O. basilicum significantly decreased the inflammatory reaction induced by carrageenan which could be related to its antioxidant effects.