RESUMEN
Chemical investigation of the ethanol extract from the whole plant of Plectranthus glandulosus led to the isolation of a new nor-triterpenoid (1) along with seventeen known compounds (2-18) including seven triterpenoids, nine flavonoids and one steroid. Their structures were established on the basis of 1D- and 2D-NMR, IR, and MS experiments, and by comparison of their spectroscopic data with those of similar compounds reported in the literature. The EtOH extract and some isolated triterpenoids (1-4 and 13) were subjected to in vitro antimicrobial assays against a panel of pathogenic microorganisms, including Gram-positive and Gram-negative bacteria, and fungi using broth microdilution method. The EtOH extract displayed moderate activity (MIC = 512 µg/mL) against Staphylococcus aureus MSSA1, Shigella flexneri SDINT and Cryptococcus neoformans H99. Compounds 1, 4 and 13 showed the most potent antimicrobial effect with MICs of 32-256 µg/mL.
Asunto(s)
Antiinfecciosos , Lamiaceae , Plectranthus , Triterpenos , Antibacterianos/química , Antiinfecciosos/química , Antiinfecciosos/farmacología , Bacterias Gramnegativas , Bacterias Grampositivas , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/química , Extractos Vegetales/farmacología , Plectranthus/química , Triterpenos/farmacologíaRESUMEN
The local botanical Imperata cylindrica in Cameroon was investigated for its antibacterial potency. The methanol extract afforded a total of seven compounds, including five hitherto unreported compounds comprising three flavonoids (1-3) and two C-15 isoprenoid analogues (4 and 5) together with known derivatives (6 and 7). The novelty of the flavonoids was related to the presence of both methyl and prenyl groups. The potential origin of the methyl in the flavonoids is discussed, as well as the chemophenetic significance of our findings. Isolation was performed over repeated silica gel and Sephadex LH-20 column chromatography and the structures were elucidated by (NMR and MS). The crude methanol extract and isolated compounds showed considerable antibacterial potency against a panel of multi-drug resistant (MDR) bacterial strains. The best MIC values were obtained with compound (2) against S. aureus ATCC 25923 (32 µg/mL) and MRSA1 (16 µg/mL).
Asunto(s)
Antibacterianos/farmacología , Flavonoides/farmacología , Poaceae/química , Prenilación , Terpenos/farmacología , Espectroscopía de Resonancia Magnética con Carbono-13 , Flavonoides/química , Flavonoides/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Espectroscopía de Protones por Resonancia Magnética , Terpenos/química , Terpenos/aislamiento & purificaciónRESUMEN
The isolation and spectroscopic data of a hitherto undescribed polyketide (1) from Hypericum roeperianum Schimp. (Hypericaceae) together with six known compounds (2-7) is herein reported. The structure elucidation is based on extensive 1D- and 2D-NMR, infrared, UV and MS experiments. The structures of the known compounds were confirmed by comparison of their spectroscopic data with those of similar reported compounds in the literature. Some of the isolated compounds had a significant activity against a panel of multidrug-resistant bacterial strains.Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1677655.
Asunto(s)
Hypericum/química , Corteza de la Planta/química , Policétidos/aislamiento & purificación , Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Policétidos/químicaRESUMEN
A new caffeate derivative from the ethanol extract of the stem bark of Cassia sieberiana DC. is described herein along with the known secondary metabolites spectaline (2), iso-6-cassine (3), 3-O-methyl-chiro-inositol (4), monobehenin (5), octyl nonadecyloate (6), ß-sitosterol (7), stigmasterol (8) and sitosterol 3-O-ß-D-glucopyranoside (9). The chemical structures were elucidated by means of various spectroscopic and spectrometric techniques. Extract and isolated compounds were devoid of inhibitory action against the herein selected bacterial strains (MICs > 256 µg/mL) but showed capacities to reduce 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (EC50 < 3 µg/mL) considerably better than the "gold standard" trolox (EC50 6.47 ± 0.48 µg/mL).
Asunto(s)
Ácidos Cafeicos/farmacología , Cassia , Depuradores de Radicales Libres/farmacología , Piperidinas/farmacología , Ácidos Cafeicos/aislamiento & purificación , Cassia/química , Depuradores de Radicales Libres/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Fitoquímicos/aislamiento & purificación , Fitoquímicos/farmacología , Piperidinas/aislamiento & purificación , Corteza de la Planta/química , Extractos VegetalesRESUMEN
Five new triterpenoids, caloncobic acids A and B (1 and 2), caloncobalactones A and B (3 and 4), and glaucalactone (5), along with the known compounds 3ß,21ß-dihydroxy-30-nor-(D:A)-friedo-olean-20(29)-en-27-oic acid (6) and acetyltrichadenic acid B (7), were isolated from the leaves of Caloncoba glauca. The structures of 1-5 were elucidated using spectroscopic methods. Compounds 1-7 were evaluated for their inhibitory activities against two isozymes of 11ß-hydroxysteroid dehydrogenase (11ß-HSD1 and 11ß-HSD2). Compounds 1 and 2 exhibited strong inhibitory activities against mouse (EC(50) 132 and 13 nM) and human (EC(50) 105 and 72 nM) 11ß-HSD1.