RESUMO
We have synthesized twenty-three 1,4-dihydropyridine derivatives (1,4-DHPs) by using a microwave-assisted one-pot multicomponent Hantzsch reaction and evaluated their antibacterial activity against a representative panel of cariogenic bacteria and their inâ vitro antileishmanial activity against Leishmania (L.) amazonensis promastigotes and amastigotes. Thirteen compounds were moderately active against Streptococcus sanguinis, Streptococcus mitis, and Lactobacillus paracasei. Compound 22 (diethyl 4-(3-methoxy-4-hydroxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate) displayed moderate antibacterial activity against S. mitis and S. sanguinis, with a Minimum Inhibitory Concentration (MIC) of 500â µg/mL); compounds 8 (ethyl 2,7,7-trimethyl-4-(3-chlorophenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate) and 10 (ethyl 2,7,7-trimethyl-4-(3-nitrophenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate) were moderately active against S. sanguinis (MIC=500â µg/mL) and very active against L. amazonensis promastigotes (IC50=43.08 and 34.29â µM, respectively). Among the eight 1,4-DHPs that were active (IC50 <50â µM) against L. amazonensis promastigotes, compound 13 (ethyl 2,7,7-trimethyl-4-(3,4,5-trimethoxyphenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate) was the most active (IC50=24.62â µM) and had a Selectivity Index (SI) higher than 4 compared to GM07492â A cells. On the other hand, compounds 7 (ethyl 2,7,7-trimethyl-4-(3-fluorophenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate) and 9 (ethyl 2,7,7-trimethyl-4-(2-nitrophenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate) were the most active against L. amazonensis amastigotes (IC50=12.53 and 13.67 µM, respectively; SI>7.9 and >7.3, respectively) after 24â h of treatment. Our results indicated that asymmetric 1,4-DHPs derived from dimedone exhibit antileishmanial potential.
RESUMO
The study aimed to assess the chemical composition of Miconia ibaguensis leaves extracts and fractions obtained from the ethanolic extract (EE), along with evaluating their antifungal, antibacterial, antidiabetic, and antioxidant activities. The ethyl acetate fraction (EAF) exhibited potent antifungal activity against Candida spp (1.95-3.90â µg mL-1) and potent antioxidant activity in the DPPH (1.74±0.07â µg mL-1), FRAP (654.01±42.09â µmol ETrolox/gsample), and ORAC (3698.88±37.28â µmol ETrolox/gsample) methods. The EE displayed inhibition against the α-amylase enzyme (8.42±0.05â µg mL-1). Flavonoids, hydrolysable tannins, triterpenoids, and phenolic acids, identified in the EE and fractions via (-)-HPLC-ESI-MS/MS analysis, were found to contribute to the species' biological activity potentially. These findings suggest promising avenues for further research and potential applications in pharmacology and natural products, offering new possibilities in the fight against global health issues.
Assuntos
Antibacterianos , Antifúngicos , Antioxidantes , Hipoglicemiantes , Melastomataceae , Testes de Sensibilidade Microbiana , Extratos Vegetais , Folhas de Planta , Folhas de Planta/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Extratos Vegetais/isolamento & purificação , Melastomataceae/química , Antioxidantes/farmacologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antifúngicos/farmacologia , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Hipoglicemiantes/farmacologia , Hipoglicemiantes/química , Hipoglicemiantes/isolamento & purificação , Candida/efeitos dos fármacos , alfa-Amilases/antagonistas & inibidores , alfa-Amilases/metabolismo , Flavonoides/química , Flavonoides/farmacologia , Flavonoides/isolamento & purificação , Cromatografia Líquida de Alta PressãoRESUMO
This updated review article covers the literature between 2011 and 2021 on the antibacterial activity of EOs against the main bacteria that cause caries and periodontal diseases. The criteria to classify the inâ vitro antibacterial activity of EOs is updated and the most promising results are addressed.
Assuntos
Óleos Voláteis , Antibacterianos/farmacologia , Bactérias , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologiaRESUMO
Brazilian green and red propolis stand out as commercial products for different medical applications. In this article, we report the antimicrobial activities of the hydroalcoholic extracts of green (EGP) and red (ERP) propolis, as well as guttiferone E plus xanthochymol (8) and oblongifolinâ B (9) from red propolis, against multidrug-resistant bacteria (MDRB). We undertook the minimal inhibitory (MIC) and bactericidal (MBC) concentrations, inhibition of biofilm formation (MICB50 ), catalase, coagulase, DNase, lipase, and hemolysin assays, along with molecular docking simulations. ERP was more effective by displaying MIC and MBC values <100â µg mL-1 . Compoundsâ 8 andâ 9 displayed the lowest MIC values (0.98 to 31.25â µg mL-1 ) against all tested Gram-positive MDRB. They also inhibited the biofilm formation of S. aureus (ATCC 43300 and clinical isolate) and S. epidermidis (ATCC 14990 and clinical isolate), with MICB50 values between 1.56 and 6.25â µg mL-1 . The molecular docking results indicated thatâ 8 andâ 9 might interact with the catalase's amino acids. Compounds 8 and 9 have great antimicrobial potential.
Assuntos
Anti-Infecciosos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Própole/química , Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Benzofenonas/química , Benzofenonas/isolamento & purificação , Benzofenonas/metabolismo , Benzofenonas/farmacologia , Sítios de Ligação , Biofilmes/efeitos dos fármacos , Brasil , Catalase/química , Catalase/metabolismo , Domínio Catalítico , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Própole/metabolismo , Própole/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologiaRESUMO
A new method of screening was developed to generate 770 organic and water-soluble fractions from extracts of nine species of marine sponges, from the growth media of 18 species of marine-derived fungi, and from the growth media of 13 species of endophytic fungi. The screening results indicated that water-soluble fractions displayed significant bioactivity in cytotoxic, antibiotic, anti-Leishmania, anti-Trypanosoma cruzi, and inhibition of proteasome assays. Purification of water-soluble fractions from the growth medium of Penicillium solitum IS1-A provided the new glutamic acid derivatives solitumine A (1), solitumine B (2), and solitumidines A-D (3-6). The structures of compounds 1-6 have been established by analysis of spectroscopic data, chemical derivatizations, and vibrational circular dichroism calculations. Although no biological activity could be observed for compounds 1-6, the new structures reported for 1-6 indicate that the investigation of water-soluble natural products represents a relevant strategy in finding new secondary metabolites.
Assuntos
Glutamatos/química , Regiões Antárticas , Fungos/química , Estrutura Molecular , Penicillium/química , ÁguaRESUMO
Considering our previous findings on the remarkable activity exhibited by cobalt(III) with 2-acetylpyridine-N(4)-R-thiosemicarbazone (Hatc-R) compounds against Mycobacterium tuberculosis, the present study aimed to explored new structure features of the complexes of the type [Co(atc--R)2]Cl, where R = methyl (Me, 1) or phenyl (Ph, 2) (13C NMR, high-resolution mass spectrometry, LC-MS/MS, fragmentation study) together with its antibacterial and antiviral biological activities. The minimal inhibitory and minimal bactericidal concentrations (MIC and MBC) were determined, as well as the antiviral potential of the complexes on chikungunya virus (CHIKV) infection in vitro and cell viability. [Co(atc-Ph)2]Cl revealed promising MIC and MBC values which ranged from 0.39 to 0.78 µg/mL in two strains tested and presented high potential against CHIKV by reducing viral replication by up to 80%. The results showed that the biological activity is strongly influenced by the peripheral substituent groups at the N(4) position of the atc-R1- ligands. In addition, molecular docking analysis was performed. The relative binding energy of the docked compound with five bacteria strains was found in the range of -3.45 and -9.55 kcal/mol. Thus, this work highlights the good potential of cobalt(III) complexes and provide support for future studies on this molecule aiming at its antibacterial and antiviral therapeutic application.
Assuntos
Cobalto/farmacologia , Tiossemicarbazonas/química , Antibacterianos/farmacologia , Antivirais/farmacologia , Bactérias/efeitos dos fármacos , Febre de Chikungunya/tratamento farmacológico , Vírus Chikungunya/efeitos dos fármacos , Cromatografia Líquida/métodos , Cobalto/química , Complexos de Coordenação/farmacologia , Ligantes , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Espectrometria de Massas em Tandem/métodos , Tiossemicarbazonas/farmacologiaRESUMO
The species Inga laurina is native to the Brazilian Cerrado. There are no studies about the chemical composition and biological activities of extracts of this endangered species. The ethanolic extract and its successive fractions are rich in phenolic compounds and presented good antifungal activities. HPLC/MS-MS/MS and H1/C13 analysis led to the identification of seventeen compounds, most of which are gallic acid derivatives, myricetin and quercetin glycosides. The ethyl acetate fraction (EAF) contained high levels of total phenolics, expressed in milligrams of gallic acid equivalents per gram of extract (475.3 ± 1.9 mg GAE gextract -1) and flavonoids expressed in milligrams of quercetin equivalents per gram of extract (359.3 ± 10.6 mg QE gextract -1). This fraction was active against fungi of the Candida genus. The EAF showed MIC value 11.7 µg mL-1 against C. glabrata and a selectivity index of 1.6 against Vero cells. The flavonol glycoside myricetin-3-O-rhamnoside was isolated for the first time from the Inga laurina. These results make I. laurina a promising plant as a source of pharmaceutical and biological active antifungal compounds.
Assuntos
Antifúngicos/farmacologia , Citotoxinas/farmacologia , Fabaceae/química , Extratos Vegetais/farmacologia , Antifúngicos/química , Antifúngicos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Citotoxinas/química , Citotoxinas/isolamento & purificação , Flavonoides/química , Flavonoides/isolamento & purificação , Fenóis/química , Fenóis/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Proantocianidinas/química , Proantocianidinas/isolamento & purificação , Espectrometria de Massas em TandemRESUMO
Tooth decay is a major public health problem which affects a large number of people in several countries. Even though more than 700 bacterial species have been detected in the oral cavity, Streptococcus and Lactobacillus stand out as the genera that cause tooth decay and other periodontal diseases. In this study, essential oils from Citrus aurantifolia leaves (CL-EO) and fruit peel (CP-EO) were obtained by hydrodistillation by a Clevenger-type apparatus whereas their chemical composition was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Limonene (77.5 %), linalool (20.1 %), citronellal (14.5 %) and citronellol (14.2 %) were the main constituents found in the essential oils from C. aurantifolia leaves and fruit peel. Antibacterial activity of essential oils was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method in 96-well microplates. Both CL-EO and CP-EO displayed some activity against all oral pathogens under investigation; MIC values ranged from 20 to 200 µg/mL. CL-EO and CP-EO not only had promising activity against Streptococcus mutans (MIC = 20 µg/mL) and Lactobacillus casei (31.25 µg/mL), but also displayed antibacterial activity against all studied cariogenic bacteria. Efficacy of essential oils against S. mutans and L. casei is noteworthy and should be further investigated.
Assuntos
Antibacterianos , Citrus/química , Cárie Dentária/tratamento farmacológico , Óleos Voláteis , Extratos Vegetais , Folhas de Planta/química , Streptococcus/efeitos dos fármacos , Monoterpenos Acíclicos , Aldeídos/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Cicloexenos/química , Cromatografia Gasosa-Espectrometria de Massas , Lacticaseibacillus casei/efeitos dos fármacos , Limoneno , Testes de Sensibilidade Microbiana , Monoterpenos/química , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Óleos Voláteis/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Terpenos/químicaRESUMO
We evaluated the antimicrobial activity of 25 monoketone curcuminoids (MKCs) against a representative panel of cariogenic bacteria in terms of their minimum inhibitory concentration (MIC) values. Curcumin A (10) displayed promising activity against Streptococcus mutans (MIC = 50 µg/ml) and Streptococcus mitis (MIC = 50 µg/ml) as well as moderate activity against S. sanguinis (MIC = 100 µg/ml), Lactobacillus casei (MIC = 100 µg/ml), and Streptococcus salivarius (MIC = 200 µg/ml). Results indicated higher activity of compound 10 than that of its bis-ß-diketone analog. Additionally, compounds 3a (1,5-bis(4-methylphenyl)pentan-3-one) and 7b (1,5-bis(4-bromophenyl)pentan-3-ol) were moderately active against S. mitis (MIC = 100 µg/ml) and S. salivarus (MIC = 200 µg/ml).
Assuntos
Antibacterianos/farmacologia , Curcumina/farmacologia , Lacticaseibacillus casei/efeitos dos fármacos , Streptococcus/efeitos dos fármacos , Antibacterianos/química , Curcumina/análogos & derivados , Curcumina/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Many essential oils (EOs) of different plant species possess interesting antimicrobial effects on buccal bacteria and antioxidant properties. Eugenia klotzschiana Berg (pêra-do-cerrado, in Portuguese) is a species of Myrtaceae with restricted distribution in the Cerrado. The essential oils were extracted through the hydrodistillation technique using a modified Clevenger apparatus (2 hours) and chemically characterized by GC-MS. The major compounds were α-copaene (10.6 %) found in oil from leaves in natura, ß-bisabolene (17.4 %) in the essential oil from dry leaves and α-(E)-bergamotene (29.9 %) in oil from flowers. The antioxidant activity of essential oils showed similarities in both methods under analysis (DPPH and ABTSË+) and the results suggested moderate to high antioxidant activity. The antibacterial activity was evaluated by determining minimum inhibitory concentrations (MICs), using the microdilution method. MIC values below 400 µg/mL were obtained against Streptococcus salivarius (200 µg/mL), S. mutans (50 µg/mL), S. mitis (200 µg/mL) and Prevotella nigrescens (50 µg/mL). This is the first report of the chemical composition and antibacterial and antioxidant activities of the essential oils of E. klotzschiana. These results suggest that E. klotzschiana, a Brazilian plant, provide initial evidence of a new and alternative source of substances with medicinal interest.
Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Eugenia/química , Flores/química , Folhas de Planta/química , Prevotella/efeitos dos fármacos , Streptococcus/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Antioxidantes/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Testes de Sensibilidade MicrobianaRESUMO
Abnormal multiplication of oral bacteria causes dental caries and dental plaque. These diseases continue to be major public health concerns worldwide, mainly in developing countries. In this study, the chemical composition and antimicrobial activity of the essential oil of Vitex agnus-castus leaves (VACâEO) collected in the North of Brazil against a representative panel of cariogenic bacteria were investigated. The antimicrobial activity of VAC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by using the broth microdilution method in 96-well microplates. The chemical constituents of VAC-EO were identified by gas chromatography (GCâFID) and gas chromatographyâmass spectrometry (GCâMS). VACâEO displayed some activity against all the investigated oral pathogens; MIC values ranged from 15.6 to 200 µg/mL. VAC-EO had promising activity against Streptococcus mutans (MIC= 15.6 µg/mL), Lactobacillus casei (MIC= 15.6 µg/mL), and Streptococcus mitis (MIC= 31.2 µg/mL). The compounds 1,8-cineole (23.8%), (E)-ß-farnesene (14.6%), (E)-caryophyllene (12.5%), sabinene (11.4%), and α-terpinyl acetate (7.7%) were the major chemical constituents of VACâEO. VAC-EO displays antimicrobial activity against cariogenic bacteria. The efficacy of VAC-EO against S. mutans is noteworthy and should be further investigated.
Assuntos
Antibacterianos/farmacologia , Cárie Dentária/tratamento farmacológico , Lacticaseibacillus casei/efeitos dos fármacos , Lamiaceae/química , Extratos Vegetais/farmacologia , Sesquiterpenos/farmacologia , Vitex/química , Antibacterianos/isolamento & purificação , Brasil , Cromatografia Gasosa-Espectrometria de Massas , Óleos Voláteis/isolamento & purificação , Óleos Voláteis/farmacologia , Plantas Medicinais , Sesquiterpenos Policíclicos , Sesquiterpenos/classificação , Streptococcus mutansRESUMO
We have investigated the chemical composition and the antibacterial activity of the essential oil of Dysphania ambrosioides (L.) Mosyakin & Clemants (Chenopodiaceae) (DA-EO) against a representative panel of cariogenic bacteria. We have also assessed the in vitro schistosomicidal effects of DA-EO on Schistosoma mansoni and its cytotoxicity to GM07492-A cells in vitro. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) revealed that the monoterpenes cis-piperitone oxide (35.2%), p-cymene (14.5%), isoascaridole (14.1%), and α-terpinene (11.6%) were identified by as the major constituents of DA-EO. DA-EO displayed weak activity against Streptococcus sobrinus and Enterococcus faecalis (minimum inhibitory concentration (MIC) = 1000 µg/ml). On the other hand, DA-EO at 25 and 12.5 µg/ml presented remarkable schistosomicidal action in vitro and killed 100% of adult worm pairs within 24 and 72 h, respectively. The LC50 values of DA-EO were 6.50 ± 0.38, 3.66 ± 1.06, and 3.65 ± 0.76 µg/ml at 24, 48, and 72 h, respectively. However, DA-EO at concentrations higher than 312.5 µg/ml significantly reduced the viability of GM07492-A cells (IC50 = 207.1 ± 4.4 µg/ml). The selectivity index showed that DA-EO was 31.8 times more toxic to the adult S. mansoni worms than GM07492-A cells. Taken together, these results demonstrate the promising schistosomicidal potential of the essential oil of Dysphania ambrosioides.
Assuntos
Chenopodiaceae/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Esquistossomicidas/química , Esquistossomicidas/farmacologia , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Chenopodiaceae/metabolismo , Enterococcus faecalis/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Lacticaseibacillus casei/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Óleos Voláteis/isolamento & purificação , Óleos Voláteis/toxicidade , Esquistossomicidas/isolamento & purificação , Streptococcus/efeitos dos fármacosRESUMO
In this work, we used the Minimum Inhibitory Concentration (MIC) technique to evaluate the antibacterial potential of the apitoxin produced by Apis mellifera bees against the causative agents of tooth decay. Apitoxin was assayed in natura and in the commercially available form. The antibacterial actions of the main components of this apitoxin, phospholipase A2, and melittin were also assessed, alone and in combination. The following bacteria were tested: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis, Lactobacillus casei, and Enterococcus faecalis. The MIC results obtained for the commercially available apitoxin and for the apitoxin in natura were close and lay between 20 and 40 µg / mL, which indicated good antibacterial activity. Melittin was the most active component in apitoxin; it displayed very promising MIC values, from 4 to 40 µg / mL. Phospholipase A2 presented MIC values higher than 400 µg / mL. Association of mellitin with phospholipase A2 yielded MIC values ranging between 6 and 80 µg / mL. Considering that tooth decay affects people's health, apitoxin and its component melittin have potential application against oral pathogens.
Assuntos
Antibacterianos/farmacologia , Venenos de Abelha/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Lacticaseibacillus casei/efeitos dos fármacos , Streptococcus/efeitos dos fármacos , Animais , Venenos de Abelha/química , Venenos de Abelha/enzimologia , Meliteno/farmacologia , Testes de Sensibilidade Microbiana , Fosfolipases A2/farmacologiaRESUMO
We report herein the synthesis of six diterpene derivatives, three of which are new, generated through known organic chemistry reactions that allowed structural modification of the existing natural products kaurenoic acid (1) and copalic acid (2). The new compounds were fully characterized using high resolution mass spectrometry, infrared spectroscopy, ¹H- and (13)C-NMR experiments. We also report the evaluation of the anti-tuberculosis potential for all compounds, which showed some promising results for Micobacterium tuberculosis inhibition. Moreover, the toxicity for each of the most active compounds was also assessed.
Assuntos
Diterpenos/síntese química , Diterpenos/farmacologia , Antituberculosos/síntese química , Antituberculosos/química , Antituberculosos/farmacologia , Produtos Biológicos , Diterpenos/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
The seasonal chemical composition of essential oils from Inga laurina was determined by GC/MS. In the stem bark's essential oil extracted during the dry season, the presence of terpenoids (30.05%) stood out, and phytol (9.76%) was the major compound identified. For the stem bark oil obtained during the rainy season, in addition to terpenoids (26.63%), a large amount of fatty acids (46.84%) were identified, in particular palmitic acid (25.40%). Regarding the leaves' essential oil obtained in the dry season, esters (42.35%) were the main components. The main ester present was (Z)-hex-3-enyl benzoate (10.15%) and the major compound of this oil was (Z)-hex-3-en-1-ol (14.23%). Terpenoids (33.84%), long-chain alkanes (27.04%) and fatty acids (21.72%) were the main components of the essential oil from leaves in the rainy season. Phytol (33.21%), nonacosane (21.95%) and palmitic acid (15.20%) were the major compounds identified. The antimicrobial activity against aerobic and anaerobic oral bacteria was evaluated by the microdilution broth method and cytotoxic activity was carried out with Vero cells. The essential oils from the rainy season showed a better inhibition of the bacterial growth with Minimal Inhibitory Concentrations (MIC) values of 25 or 50 µg·mL⻹ for aerobic bacteria, and high selectivity against bacteria was observed. The large amount of fatty acids in rainy season oils may be related to the better inhibitory effects observed.
Assuntos
Anti-Infecciosos/química , Citotoxinas/química , Fabaceae/química , Óleos Voláteis/química , Óleos de Plantas/química , Animais , Anti-Infecciosos/farmacologia , Bactérias Aeróbias/efeitos dos fármacos , Bactérias Aeróbias/crescimento & desenvolvimento , Bactérias Anaeróbias/efeitos dos fármacos , Bactérias Anaeróbias/crescimento & desenvolvimento , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Citotoxinas/farmacologia , Ésteres , Ácidos Graxos/classificação , Ácidos Graxos/isolamento & purificação , Óleos Voláteis/farmacologia , Especificidade de Órgãos , Casca de Planta/química , Folhas de Planta/química , Óleos de Plantas/farmacologia , Estações do Ano , Terpenos/classificação , Terpenos/isolamento & purificação , Células VeroRESUMO
Callistemon viminalis has been widely known due to its therapeutic properties. Tuberculosis is a deadly infectious disease caused predominantly by Mycobacterium tuberculosis. Other respiratory diseases may also be caused by nontuberculous mycobacteria. Malassezia furfur causes dermal inflammation and tissue damage. This study aimed to evaluate in vitro inhibitory effects of essential oils (EOs) from C. viminalis leaves (EO-CL) and flowers (EO-CF) against M. tuberculosis, Mycobacterium kansasii, Mycobacterium avium and M. furfur strains. Their cytotoxic activity was evaluated by the brine shrimp assay. Resulting MIC values of all EOs under study were promising since they ranged from 50 to 100 µg/mL. Both EO-CL and EO-CF showed nontoxicity against Artemia salina by the brine shrimp assay (LC50 > 1000 µg/mL). GC-FID and GC-MS analyses showed that 1,8-cineole was the major component of both EOs. These results revealed the promising potential of EO-CL and EO-CF to develop new antibacterial and antifungal drugs.
RESUMO
Artepillin C, drupanin, and plicatin B are prenylated phenylpropanoids that naturally occur in Brazilian green propolis. In this study, these compounds and eleven of their derivatives were synthesized and evaluated for their in vitro antimicrobial activity against a representative panel of oral bacteria in terms of their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Plicatin B (2) and its hydrogenated derivative 8 (2',3',7,8-tetrahydro-plicatin B) were the most active compounds. Plicatin B (2) displayed strong activity against all the bacteria tested, with an MIC of 31.2 µg/mL against Streptococcus mutans, S. sanguinis, and S. mitis. On the other hand, compound 8 displayed strong activity against S. mutans, S. salivarius, S. sobrinus, Lactobacillus paracasei (MIC = 62.5 µg/mL), and S. mitis (MIC = 31.2 µg/mL), as well as moderate activity against Enterococcus faecalis and S. sanguinis (MIC = 125 µg/mL). Compounds 2 and 8 displayed bactericidal effects (MBC: MIC ≤ 4) against all the tested bacteria. In silico studies showed that the complexes formed by compounds 2 and 8 with the S. mitis, S. sanguinis, and S. mutans targets (3LE0, 4N82, and 3AIC, respectively) had energy score values similar to those of the native S. mitis, S. sanguinis, and S. mutans ligands due to the formation of strong hydrogen bonds. Moreover, all the estimated physicochemical parameters satisfied the drug-likeness criteria without violating the Lipinski, Veber, and Egan rules, so these compounds are not expected to cause problems with oral bioavailability and pharmacokinetics. Compounds 2 and 8 also had suitable ADMET parameters, as the online server pkCSM calculates. These results make compounds 2 and 8 good candidates as antibacterial agents against oral bacteria.
RESUMO
The present study describes the antimicrobial activity of five pimarane-type diterpenes obtained by fungal biotransformation against several nosocomial multidrug-resistant bacteria. Among the investigated metabolites, ent-8(14),15-pimaradien-3ß-ol was the most active compound, with very promising minimal inhibitory concentration values (between 8.0 and 25.0 µg mL(-1)). Time-kill assays using this metabolite against Staphylococcus aureus (HCRP180) revealed that this compound exerted its bactericidal effect within 24 h at all the evaluated concentrations (8.0, 16.0, and 24.0 µg mL(-1)). When this metabolite was associated with vancomycin at their minimal bactericidal concentration values, the resulting combination was able to drastically reduce the number of viable strains of S. aureus within the first 6 h, compared with these chemicals alone. The checkerboard assays conducted against this microorganism did not evidence any synergistic effects when this same combination was employed. In conclusion, our results point out that ent-8(14),15-pimaradien-3ß-ol is an important metabolite in the search for new effective antimicrobial agents.
Assuntos
Abietanos/farmacologia , Antibacterianos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Abietanos/química , Abietanos/isolamento & purificação , Antibacterianos/química , Antibacterianos/isolamento & purificação , Aspergillus ochraceus/metabolismo , Asteraceae/química , Biotransformação , Farmacorresistência Bacteriana Múltipla , Testes de Sensibilidade Microbiana , Raízes de Plantas/química , Vancomicina/farmacologiaRESUMO
We evaluated the antibacterial activity of three diterpenes isolated from natural sources against a panel of microorganisms responsible for bovine mastitis. ent-Copalic acid (CA) was the most active metabolite, with promising MIC values (from 1.56 to 6.25 µg mL-1) against Staphylococcus aureus (ATCC and clinical isolate), Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus dysgalactiae. We conducted time-kill assays of CA against S. aureus, a commensal organism considered to be a ubiquitous etiological agent of bovine mastitis in dairy farms worldwide. In the first 12 h, CA only inhibited the growth of the inoculums (bacteriostatic effect), but its bactericidal effect was clearly noted thereafter (between 12 and 24 h). In conclusion, CA should be considered for the control of several Gram-positive bacteria related to bovine mastitis.
Assuntos
Diterpenos/farmacologia , Mastite Bovina/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Bovinos , Diterpenos/química , Feminino , Mastite Bovina/microbiologia , Mikania/química , Extratos Vegetais/farmacologia , Staphylococcus aureus/patogenicidadeRESUMO
The chemical composition of the essential oils from leaves, bark and wood of Cassia bakeriana Craib. was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Alcohols, aldehydes and fatty acids were the major components in leaf and bark oil, while wood essential oil was rich in fatty acids. Terpenes such as linalool, (E)-nerolidol and phytol were present in low concentrations. The antimicrobial activity against aerobic and anaerobic oral bacteria was evaluated using the microdilution method, as was the cell viability test carried out with Vero cells. The oils from leaves and bark showed high antimicrobial activity, with minimum inhibitory concentrations between 62.5 and 125 µg·mL⻹ for most of the tested bacteria, including Streptococcus mutans, the main etiological agent of dental caries. Leaves oil displayed the lowest cytotoxic effect (EC50 of 153 µg·mL⻹), while wood oil exhibited the highest toxicity to Vero cells. C. bakeriana oils are thus a source of biologically active compounds against aerobic and anaerobic oral microorganisms. This study is the first report on the chemical composition, antimicrobial activity and cytotoxicity of C. bakeriana.