Anti-inflammatory and analgesic effects of Bi-yuan-ling granules

Bi-yuan-ling granule (BLG) is a traditional Chinese medicine compound composed mainly of baicalin and chlorogenic acid. It has been demonstrated to be clinically effective for various inflammatory diseases such as acute rhinitis, chronic rhinitis, atrophic rhinitis and allergic rhinitis. However, the underlying mechanisms of BLG against these diseases are not fully understood. This study aimed to explore the anti-inflammatory and analgesic activities of BLG, and examine its protective effects on mouse acute lung injury (ALI). The hot plate test and acetic acid-induced writhing assay in Kunming mice were adopted to evaluate the pain-relieving effects of BLG. The anti-inflammatory activities of BLG were determined by examining the effects of BLG on xylene-caused ear swelling in Kunming mice, the cotton pellet-induced granuloma in rats, carrageenan-induced hind paw edema and lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. The results showed that BLG at 15.5 mg/g could significantly relieve the pain by 82.5% (P<0.01) at 1 h after thermal stimulation and 91.2% (P<0.01) at 2 h after thermal stimulation. BLG at doses of 7.75 and 15.5 mg/g reduced the writhing count up to 33.3% (P<0.05) and 53.4% (P<0.01), respectively. Additionally, the xylene-induced edema in mice was markedly restrained by BLG at 7.75 mg/g (P<0.05) and 15.5 mg/g (P<0.01). BLG at 5.35 and 10.7 mg/g significantly reduced paw edema by 34.8% (P<0.05) and 37.9% (P<0.05) at 5 h after carrageenan injection. The granulomatous formation of the cotton pellet was profoundly suppressed by BLG at 2.68, 5.35 and 10.7 mg/g by 15.4%, 38.2% (P<0.01) and 58.9% (P<0.001), respectively. BLG also inhibited lung W/D ratio and the release of prostaglandin E2 (PGE2) in ALI mice. In addition, the median lethal dose (LD50), median effective dose (ED50) and half maximal inhibitory concentration (IC50) of BLG were found to be 42.7, 3.2 and 12.33 mg/g, respectively. All the findings suggest that BLG has significantly anti-inflammatory and analgesic effects and it may help reduce the damage of ALI.