RESUMEN
Lactuca indica (Compositae) is an edible wild vegetable, used as a folk medicine in anti-inflammatory, antibacterial, and other medications in Asia. This is the first scientific evaluation of the chemopreventive therapeutic properties of L. indica using five antioxidation assay systems. An extract from L. indica was found to possess significant free radical scavenging activity, effectively protecting phix174 supercoiled DNA against strand cleavage and reducing oxidative stress in human promyelocytic leukemia HL-60 cells. Moreover, extracts of L. indica almost totally inhibited nitric oxide production and the mRNA expression of inducible nitric oxide synthase, at a dosage of 100 microg/mL, in LPS-stimulated macrophage RAW264.7 cells. Bioactivity-guided chromatographic fractionation and metabolite profiling coupled with spectroscopic analyses revealed that the six phenolic compounds, that is, protocatechulic acid (1), methyl p-hydroxybenzoate (2), caffeic acid (3), 3,5-dicaffeoylquinic acid (4), luteolin 7-O-beta-glucopyranoside (5), and quercetin 3-O-beta-glucopyranoside (6), are the major antioxidative constituents in the L. indica extract.
Asunto(s)
Antioxidantes/análisis , Lactuca/química , Extractos Vegetales/análisis , Antioxidantes/farmacología , Línea Celular , Cromatografía Líquida de Alta Presión , Daño del ADN/efectos de los fármacos , Depuradores de Radicales Libres/análisis , Depuradores de Radicales Libres/farmacología , Expresión Génica/efectos de los fármacos , Células HL-60 , Humanos , Radical Hidroxilo/farmacología , Macrófagos/enzimología , Óxido Nítrico Sintasa/genética , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Estrés Oxidativo/efectos de los fármacos , Fenoles/análisis , Fenoles/farmacología , Extractos Vegetales/farmacología , ARN Mensajero/análisis , Superóxidos/químicaRESUMEN
Phytochemical characteristics and antioxidant activities of the crude and fractionated plant extracts of Anoectochilus formosanus were evaluated using five different assay systems. An acid-treatment (2 N HCl in 95% ethanol) was employed to treat a butanol fraction (BuOH), creating an acid-hydrolyzed BuOH fraction. The IC(50) values for DPPH radicals in the BuOH and acid-hydrolyzed BuOH fractions were 0.521 and 0.021 mg/mL, respectively. The acid-hydrolyzed BuOH exhibited approximately 5-fold higher activity in scavenging superoxide anion than catechin. The acid-hydrolyzed BuOH fraction also effectively protected phi x174 supercoiled DNA against strand cleavage induced by H(2)O(2) and reduced oxidative stress in HL-60 cells. Metabolite profiling showed that the aglycones of flavonoid glycosides in BuOH were produced after acid hydrolytic treatment, and this resulted in a significant increase in antioxidant activities of acid-hydrolyzed BuOH. One new diarylpentanoid, kinsenone, and three known flavonoid glycosides and their derivatives were identified for the first time from A. formosanus, with strong antioxidant properties.