Hepatoprotective and antioxidant activities of the aqueous extract from the rhizome of Phragmites australis.

The rhizome of Phragmites australis has long been used for the treatment of hepatitis in traditional Chinese medicine. In this study, the hepatoprotective and antioxidant activities of an aqueous extract from the rhizome of P. australis (AE-PA) were evaluated. The acute toxicity test in mice showed that AE-PA was nontoxic since a dose of 2000 mg/kg body weight (b.w.) did not cause toxic symptoms or mortality. The prolongation of hexobarbital-induced sleeping time by carbon tetrachloride (CCl4) administration to mice was significantly reduced after pretreatment with AE-PA at 500 mg/kg b.w., proving the protective effect of the extract on microsomal drug-metabolizing enzyme. The oral administration of AE-PA to rats for 5 days before CCl4 intoxication caused a significant decrease in the CCl4-induced elevation of hepatic enzymes activities in serum, such as aspartate aminotransferase, alanine aminotransferase, and lactic acid dehydrogenase. This suggested that AE-PA had good hepatoprotective activity against CCl4-induced liver injury, which was confirmed by pathomorphological examination of the liver. Through evaluation of hydroxyl radical and superoxide anion radical scavenging activities, respectively, it was demonstrated that AE-PA had good antioxidant activity, which possibly contributed to its hepatoprotective activity. More research is needed to study the bio-active compounds in P. australis and to identify the potential hepatoprotective and antioxidant agents.