RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Parastrephia lucida (Meyen) Cabrera is used in the traditional medicine of Argentinean highlands as an antiseptic and anti-inflammatory medicinal plant. To give scientific support to the ethnopharmacological claim of Parastrephia lucida as an anti-inflammatory crude drug the effect of Parastrephia lucida extracts and fractions was assessed on key enzymes of the biosynthesis of pro-inflammatory eicosanoids mediators from arachidonic acid (AA). MATERIALS AND METHODS: A bio-guided fractionation of the plant extract was carried out to find out the compounds or mixtures responsible for the anti-inflammatory effect. The extracts and fractions were tested in vitro for their ability to inhibit the enzymes cyclooxygenase (COX)-1 and COX-2, lipoxygenase (LOX) and phospholipase (sPLA2). Fractions were analyzed by HPLC-MS, HPLC-ESI-MS/MS and NMR to relate the effect with groups of secondary metabolites. RESULTS: Parastrephia lucida was more effective inhibiting COX and sPLA2 than LOX. Assay-guided isolation led to the active fractions C and F which showed different effect on the selected enzymes. The fraction C was more effective inhibiting LOX while fraction F showed better activity against sPLA2 and COX-2. Both fractions were further worked-up following the isolation of the anti-inflammatory agents with the selected enzyme assays. The main compounds identified in the most active fractions were 5,4'-dihydroxi-7-methoxyflavanone, apigenin, apigenin methyl ether and apigenin trimethyl ether, methyl and dimethyl ethers from quercetin, kaempferol and luteolin methyl ether, ferulic acid esters, cinnamic acid and vanillin. CONCLUSIONS: Parastrephia lucida extract inhibit AA metabolism via several enzymes. The results give support to the traditional use of this plant for the treatment of inflammatory disorders.
Assuntos
Anti-Inflamatórios/farmacologia , Asteraceae , Inibidores de Ciclo-Oxigenase/farmacologia , Inibidores de Lipoxigenase/farmacologia , Inibidores de Fosfolipase A2/farmacologia , Extratos Vegetais/farmacologia , Ácido Araquidônico/metabolismo , Argentina , Benzotiazóis/metabolismo , Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Ferro/metabolismo , Lipoxigenase/metabolismo , Medicina Tradicional , Fosfolipases A2/metabolismo , Componentes Aéreos da Planta , Ácidos Sulfônicos/metabolismoRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: The Argentinean highland plant Parastrephia lucida (Meyen) Cabrera is used in traditional medicine as an antiseptic and anti-inflammatory crude drug. AIM OF THE STUDY: To relate the antimicrobial effect of the crude drug with the constituents of the active fractions and traditional use. MATERIALS AND METHODS: Assay-guided isolation of the methanol (MeOH) plant extract was carried out using bacteria and yeasts as target organisms. Both ATCC and local strains were included in the study. The antimicrobial fractions and compounds were detected by bioautographic assays. Minimum inhibitory concentrations (MIC) of each extract and fraction were determined and compared with reference antibiotics. Fractions were analyzed by HPLC-DAD, GC-MS, (1)H NMR and (13)C NMR. RESULTS: From the MeOH extract of the plant, assay-guided isolation of the antimicrobial constituents led to 12 phenylpropanoids and two simple phenolics. Most of the compounds occurring in the active fractions were E-caffeoyl or E-cinnamoyl esters including prenyl and phenethyl derivatives. The MIC values of the most active fractions ranged between 12.5 and 200 µg/mL against reference strains and local isolates of Staphylococcus aureus and Enterococcus faecalis. CONCLUSIONS: The antimicrobial effect found in the crude drug was associated with mixtures of phenylpropanoids, including prenyl and phenethyl esters of caffeic and cinnamic acids. The results support at least in part the traditional use of the plant as local antiseptic.