Antioxidant and anti‐inflammatory activities of water distillate and its dichloromethane extract from licorice root (Glycyrrhiza uralensis) and chemical composition of dichloromethane extract

BACKGROUND: Licorice root is one of the most widely used medicinal herbs and its medicinal properties, such as antibacterial, anti‐ulcer, anti‐tumorigenic and anti‐atherosclerotic activities, have been widely reported. However, there are only a few reports on basic chemical and biological studies of the water distilled components of licorice root. RESULTS: Chinese licorice root was water distilled and the distillate was subsequently extracted with dichloromethane. Residual aqueous solution from the extraction was fractionated using column chromatography. A total of 127 chemicals were identified in the dichloromethane extract, which inhibited hexanal oxidation by over 90% for 45 days at the level of 50 µg mL^?1. A fraction eluted from the residual aqueous solution with acetone exhibited potent antioxidant activities both in a thiobarbituric acid assay and in a malonaldehyde/gas chromatography assay. The acetone fraction also exhibited strong anti‐inflammatory activity (77.9% inhibition at the level of 62 µg mL^?1) in a lipoxygenenase inhibitor screening anti‐inflammatory assay. CONCLUSION: This study demonstrated the antioxidant and anti‐inflammatory activities of the water distillate obtained from Chinese licorice root. Some volatile chemicals among the many components identified in the water distillate exhibited antioxidant activity, suggesting that many medicinal compounds escape with water vapor into the ambient air during the preparation of herbal medicine. Copyright © 2008 Society of Chemical Industry