RESUMO
Seventeen sesquiterpene lactones (SLs) isolated from five species of the tribe Vernonieae were evaluated for their in vitro activity against promastigotes of Leishmania amazonensis and Leishmania braziliensis. Additionally, a quantitative structure activity relationship has been made, since all these natural compounds were found to have potent to mild antileishmanial properties. The most active compounds against L. braziliensis were 16 and 17 (IC50 values 1.45 and 1.34 µM, respectively), followed by compound 15 with IC50 value of 1.60 µM against L. amazonensis. The three glaucolide-type SLs (4-6) were the least active against both parasites. The computational study allowed us to establish that lipophilicity and polarisability play an important role in the antiparasitic activity. This is the first report of the known germacradiendiolides 16 and 17 from Elephantopus mollis. The activity data of the compounds 1-17 assayed against Leishmania parasites are reported here for the first time.
RESUMO
CONTEXT: The use of many traditional medicinal plants is often hampered by the absence of a proper biochemical characterization, which is essential to identify the bioactive compounds present in it. The essential oils (EOs) of three native species from the La Rioja province were analyzed: Lippia turbinata Griseb and Lippia integrifolia (Griseb.) Hieron (Verbenaceae), and Clinopodium gilliesii (Benth.) Kuntze (Lamiaceae). OBJECTIVE: The aim of this study was to evaluate their EOs antioxidant activity (AA) and their chemical composition. MATERIALS AND METHODS: EOs were analyzed by gas chromatography-mass spectrometry (GC-MS). To enhance the aqueous solubilization of the EOs, EO-water emulsions were prepared (concentration range of 0.1-6 mg mL(-1)). AA was determined using ABTS, DPPH, and peroxyl radical scavenging assays, as well as by the ß-carotene bleaching test. RESULTS: Piperitenone oxide was a major constituent in L. turbinata, pulegone and piperitenone oxide in C. gilliesii, and ß-caryophyllene in L. integrifolia. Lippia turbinata EO was the most active ABTS and DPPH radical scavenger (SC50 values of 0.40 ± 0.14 and 0.74 ± 0.08 mg mL(-1), respectively). Clinopodium gilliesii EO exhibited the highest hydrogen peroxide scavenging activity (SC25 value = 1.52 ± 0.27 mg mL(-1)). In the ß-carotene assay, L. turbinata EO was more effective at inhibiting lipid peroxidation than the other two oils (IC25 value = 0.15 ± 0.04 mg mL(-1)). CONCLUSION: Our results suggest that the AA observed can be justified by the presence of oxygenated monoterpenes, mainly piperitenone oxide. Finally, L. turbinata EO might be used as a safe natural antioxidant and food preservative in the food and cosmetic industries.
Assuntos
Sequestradores de Radicais Livres/farmacologia , Lamiaceae/química , Lippia/química , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Óleos de Plantas/farmacologia , Verbenaceae/química , Argentina , Benzotiazóis/química , Compostos de Bifenilo/química , Relação Dose-Resposta a Droga , Emulsões , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Peroxidação de Lipídeos/efeitos dos fármacos , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Oxirredução , Fitoterapia , Picratos/química , Componentes Aéreos da Planta , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Óleos de Plantas/química , Óleos de Plantas/isolamento & purificação , Plantas Medicinais , Ácidos Sulfônicos/química , Fatores de Tempo , beta Caroteno/químicaRESUMO
Four fusicoccane-type diterpenoids (1-4), including the new 1 and 2; four pinguisane-type sesquiterpenoids (5-8); and two aromadendrane-type sesquiterpenoids (9 and 10) were isolated from an Argentine collection of the endemic liverwort Porella chilensis. The biofilm formation of the human pathogen Pseudomonas aeruginosa was inhibited by compounds 3 (53 and 47%), 9 (45 and 41%), and 10 (48 and 37%) at 50 and 5 µg/mL, respectively. Compounds 3, 9, and 10 also produced a slight decrease in bacterial growth and interfere with the process of quorum sensing at the same doses.