Hepatoprotective Effect of Flavonoid Glycosides from Lespedeza cuneata against Oxidative Stress Induced by tert-Butyl Hyperoxide

• Published in: Phytotherapy research 2011-07, Vol.25 (7), p.1011-1017
• Main Authors: Kim, Sang Min, Kang, Kyungsu, Jho, Eun Hye, Jung, Yu-Jin, Nho, Chu Won, Um, Byung-Hun, Pan, Cheol-Ho
• Format: Article
• Language: English
• Subjects: avicularin; Biological and medical sciences; Chemical Fractionation; Flavonoids - isolation & purification; Flavonoids - pharmacology; Free Radical Scavengers - isolation & purification; Free Radical Scavengers - pharmacology; General pharmacology; Glycosides - isolation & purification; Glycosides - pharmacology; Hep G2 Cells; hepatoprotective effect; hirsutrin; Humans; Lespedeza - chemistry; Lespedeza cuneata; Medical sciences; Oxidative Stress - drug effects; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Plant Extracts - pharmacology; Protective Agents - isolation & purification; Protective Agents - pharmacology; quercetin; radical scavenging activity; tert-Butylhydroperoxide
• ISSN: 0951-418X; 1099-1573
• DOI: 10.1002/ptr.3387

The aerial parts of Lespedeza cuneata G. Don, perennial legume native to Eastern Asia, have been used therapeutically in traditional Asian medicine to protect the function of liver, kidneys and lungs. However, little is known about the pharmaceutical effect of extracts from this plant. In the present study, the aerial parts of L. cuneata were used to prepare an ethanol extract, which was then tested for hepatoprotective effects against injury by tert‐butyl hyperoxide (t‐BHP). At a dose of 20 μg/mL, the ethanol extract significantly protected HepG2 cells against the cytotoxicity of t‐BHP. Further fractionation of the extract with ethyl acetate allowed the isolation of five flavonoid compounds that were structurally identified by 1H and 13C NMR spectroscopy as isovitexin, hirsutrin, trifolin, avicularin and quercetin. Hirsutrin, avicularin and quercetin (10 μm) showed clear hepatoprotective activity against injury by t‐BHP in HepG2 cells, whereas isovitexin and trifolin showed no protective effects. The observed hepatoprotective effect of the investigated compounds showed a high correlation with radical scavenging activity, which followed the structure–activity relationships of the flavonoid aglycones. Copyright © 2011 John Wiley & Sons, Ltd.