Chemical profile and anti-inflammatory activity of total flavonoids from Glycyrrhiza uralensis Fisch

Glycyrrhiza uralensis Fisch. (G. uralensis) is one of the most widely used herbal medicines for the treatment of cough, spasms, pain, inflammation and low immunity This study was designed to enrich total flavonoids (TFF) from G. uralensis and investigate the anti-inflammatory activity of TFF. The anti-inflammatory activity was evaluated by inflammatory models of dimethylbenzene (DMB)-induced ear vasodilatation in mice and carrageenan-induced paw edema in rats. The chemical profiling of TFF was identified by HPLC and colorimetric assay. The TFF mainly contained liquiritin apioside, liquiritin, isoliquiritin apioside, liquiritigenin and isoliquiritigenin without glycyrrhizic acid. Treatment with TFF showed significant anti-inflammatory activities at two models. In the rat paws with carrageenan, TFF at the dose of 500 mg/kg significantly inhibited the edema formation at 1 to 5 h compared to control group. But TFF at dose of 250 and 125 mg/kg only significantly decreased the edema at 2 to 5 h. Application of TFF (500 and 250 mg/kg) significantly reduced the expression of IL-1β and iNOS. TFF at all doses noticeably declined levels of NO and MDA into the site of inflammation, while only i. g. TFF at a dose of 500 mg/kg significantly decreased TNF-α levels in the carrageenan-injected paws. In addition, the increase of SOD level was showed by TFF at all doses. Our results revealed that TFF exhibited significant anti-inflammatory activity in acute inflammatory models. The activity maybe mainly contributed by liquiritin apioside, liquiritin, isoliquiritin apioside, liquiritigenin and isoliquiritigenin.