Secoiridoid content and hepatoprotective activity of Gentiana cruciata L. root extract

Abstract

Gentiana plants are best known for their bitter taste that is due to the secoiridoids (e.g. swertiamarin, gen­tiopicrin, sweroside and amarogentin). Secoiridoid glucosides, gentiopicrin, swertiamarin and sweroside, are present in various traditional medicine preparations and are reported to have hepatoprotective activity. Many Gentiana species are known for their pharmaceutical values, such as Gentiana cruciata L., commonly called cross gentian. The dried roots and above-ground parts of G. cruciata are consumed in the Balkan region as herbal tea or a medicinal wine for loss of appetite, as a stomachic and component in preparations showing benefi­cial effects in gall and liver diseases. This study using in vivo model investigates hepatoprotective activity of the methanol extract of G. cruciata root (GCR) against carbon tetrachloride-induced liver injury in rats. Wistar rats were orally pretreated with GCR (100, 200, and 400 mg/kg) and silymarin (100 mg/kg) for seven days be­fore they were treated with CCl4 (1 ml/kg, 1 :1 mixture in olive oil) which caused liver injury. Pretreatment with GCR dose-dependently and significantly (p < 0.001) decreased levels of serum transaminases, alkaline phos­phatase and total bilirubin, where as an increase was found in the level of total protein compared with CCl4-treated group. In the liver tissue antioxidant studies, we found a significant increase in the levels of catalase, superoxide dismutase and reduced glutathione, whereas there was marked reduction in the levels of thiobar­bituric acid-reactive substances, as compared to CC14 treated group. Histological analyses also show that GCR reduced the incidence of liver lesions including necrosis, ballooning degeneration and micro- and macrove­sicular changes induced by CC14 in rats. The main secoiridoid compounds (sweroside, swertiamarin and gen­tiopicrin) present in GCR were identified and quantified to gain an insight into the compounds responsible for its hepatoprotective effects. The HPLC assay clearly indicated that GCR contained the greatest concentra­tion of gentiopicrin (5.45%), whereas concentration of sweroside (0.29%) and swertiamarin (0.09%) were lower.