RESUMEN
Eragrostis plana (Nees) (Tough Lovegrass) shows ability to interfere with other plants, a phenomenon known as allelopathy. This chemical interaction between plants occurs due to the release of compounds into the environment. Thus, a phytotoxicity study was carried out with E. plana roots collected during each season throughout the year, and the compounds were extracted with solvents of increasing polarity. The data from the bioassays were analyzed by GLM and PCA. In addition, a fingerprint of these extracts was obtained by HPLC-DAD. The extracts in petroleum ether from roots collected in the winter and summer showed greater phytotoxicity on Ipomoea grandifolia germination and growth. The PCA obtained from the chromatogram of the crude extract showed that the extracts in petroleum ether were chemically different from the extracts in ethyl acetate and methanol. Thus, continuing this study in order to develop a new generation of bio-herbicides is essential.
Asunto(s)
Eragrostis , Alelopatía , Bioensayo , Cromatografía Líquida de Alta Presión , Extractos Vegetales/toxicidad , Raíces de PlantasRESUMEN
The objective of this study was to determine the chemical profile and to evaluate the antibacterial activity of the essential oils of Piper species and modulation of the antibiotic activity, using the microdilution method to determine the minimum inhibitory concentration. The chemical components were characterized by gas chromatography coupled to mass spectrometry, which revealed ß-copaen-4-α-ol (31.38%), spathulenol (25.92%), and germacrene B (21.53%) as major constituents of the essential oils of Piper arboreum, Piper aduncum, and Piper gaudichaudianum, respectively. The essential oils analyzed in this study did not present a clinically relevant activity against standard and multiresistant Escherichia coli. However, in the case of multiresistant Staphylococcus aureus, there was a significant activity, corroborating with reports in the literature, where Gram-positive bacteria are more susceptible to antimicrobial activity. The essential oils modulated the effect of the antibiotics norfloxacin and gentamicin, having on the latter greater modulating effect; however, for erythromycin, no statistically significant effect was observed. In conclusion, the results obtained in this study demonstrated that the essential oils of the analyzed Piper species present an inhibitory effect against S. aureus and modulate antibiotic activity, most of which presents synergistic activity.
Asunto(s)
Antibacterianos/química , Aceites Volátiles/química , Piper/química , Aceites de Plantas/química , Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Aceites Volátiles/farmacología , Aceites de Plantas/farmacología , Sesquiterpenos/análisis , Sesquiterpenos de Germacrano/análisis , Staphylococcus aureus/efectos de los fármacosRESUMEN
The indiscriminate use of antibiotics has made bacterial resistance an important public health problem, since many antibiotics have become ineffective. Phototherapy can be considered an alternative to reduce the abusive use of antimicrobials, thus impacting microbial resistance. The objective of this study was to determine the chemical profile and to evaluate the effect of blue LED lights on the antibacterial activity of essential oils from Piper species, as well as their aminoglycoside antibiotic activity modulation using the microdilution method to determine the Minimum Inhibitory Concentration (MIC). The antibiotic activity modulating effect of these oils was also determined using the broth microdilution method with 96-well plates which were exposed to LED light for 20â¯min. Chemical components were characterized by gas chromatography coupled to mass spectrometry, revealing ß-copaen-4-α-ol, germacrene A and germacrene B as major essential oil constituents for Piper arboreum (OEPar), Piper aduncum (OEPad) and Piper gaudichaudianum (OEPg), respectively. OEPar obtained a MIC of 512⯵g/mL against Staphylococcus aureus and a MICâ¯≥â¯1024⯵g/mL against Escherichia coli. OEPad and OEPg showed MIC valuesâ¯≥â¯1024⯵g/mL against the utilized strains. The essential oils modulated the effect of the antibiotics amikacin and gentamicin, with this effect being potentiated when exposed to blue LED. The blue LED light in the absence of the essential oil also showed an ability to modulate aminoglycoside antibiotic activity in this study, presenting mostly synergistic effects. In conclusion, the results obtained in this study demonstrate that photodynamic therapy using blue LED light interferes with the antibacterial action of P. arboreum, P. aduncum and P. gaudichaudianum essential oils and aminoglycoside antibiotic activity.
Asunto(s)
Antibacterianos/química , Aceites Volátiles/química , Fotoquimioterapia/métodos , Piper/química , Extractos Vegetales/química , Aceites de Plantas/química , Amicacina/farmacología , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Sinergismo Farmacológico , Gentamicinas/farmacología , Luz , Pruebas de Sensibilidad Microbiana , Aceites Volátiles/farmacología , Extractos Vegetales/farmacología , Aceites de Plantas/farmacologíaRESUMEN
Phytochemical investigation of the bark of Guatteria friesiana afforded 12 new aporphines (1-12), along with nine known alkaloids (13-21). The structures of the new alkaloids were determined on the basis of spectroscopic data interpretation. The cytotoxic activity of the isolated compounds against a small panel of tumor cell lines was assessed using the Alamar blue assay.
Asunto(s)
Alcaloides/aislamiento & purificación , Antineoplásicos Fitogénicos/aislamiento & purificación , Aporfinas/aislamiento & purificación , Guatteria/química , Corteza de la Planta/química , Alcaloides/química , Alcaloides/farmacología , Animales , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/farmacología , Aporfinas/química , Aporfinas/farmacología , Brasil , Ensayos de Selección de Medicamentos Antitumorales , Células HL-60 , Células Hep G2 , Humanos , Ratones , Estructura Molecular , Resonancia Magnética Nuclear BiomolecularRESUMEN
Phytochemical investigation of the bark of Guatteria hispida afforded three new alkaloids, 9-methoxy-O-methylmoschatoline (1), 9-methoxyisomoschatoline (2), and isocerasonine (3), along with 10 known alkaloids, 8-oxopseudopalmatine (4), O-methylmoschatoline (5), lysicamine (6), liriodenine (7), 10-methoxyliriodenine (8), nornuciferine (9), anonaine (10), xylopine (11), coreximine (12), and isocoreximine (13). The major compounds, 2, 6, 12, and 13, showed significant antioxidant capacity in the ORAC(FL) assay. Compounds 5, 6, and 7 were active against S. epidermidis and C. dubliniensis, with MIC values in the range 12.5-100 microg mL(-1).