Abstract

The active components and protective activity of Taraxacum coreanum from oxidative stress under in vitro and cellular system using LLC-PK₁ renal epithelial cells were investigated. T. coreanum was extracted with methanol (MeOH) and then fractionated into four different layers, n-hexane, trichloromethane (CHCl₃), ethyl acetate (EtOAc), and n-butanol (n-BuOH). In vitro, the scavenging activities of the extract and fractions from T. coreanum and its active components, luteolin and luteoloside, on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical (·OH) were measured. In LLC-PK₁cellular model, the protective activity of the EtOAc fraction, and the active components from oxidative stress induced by 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH), a generator of peroxyl radicals, were studied. Among the fractions, the EtOAc fraction and its active components, luteolin and luteoloside, exerted the strongest protective effect from DPPH and ·OH. Furthermore, the LLC-PK₁ cells showed a decrease in cell viability and an increase in lipid peroxidation by the treatment of AAPH. However, the EtOAc fraction and its active components led to the significant increases in the cell viability and inhibition in lipid peroxidation. The present results indicated that T. coreanum and its active components, luteolin and luteoloside, are promising antioxidants with the protective effect from oxidative stress induced by overproduction of free radical.

Key words: Oxidative stress, free radical, LLC-PK₁ cell, Taraxacum coreanum, luteolin, luteoloside.