ABSTRACT
AIMS: The objective of this study was to investigate the effectiveness of (+)-ß-pinene inhibition on Candida spp. growth, aiming at elucidation of the mechanism of action; to determine fungal cell enzyme binding activity (through molecular docking simulations) and its effects on biofilm reduction. METHODS: Candida strains (n=25) from referenced and clinical origins, either susceptible or resistant to standard clinical antifungals, were tested for determination of Minimum Inhibitory Concentration (MIC); Minimum Fungicidal Concentration (MFC); and microbial death curves upon treatment with (+)-ß-pinene; the effects of (+)-ß-pinene on the cell wall (sorbitol assay), membrane ergosterol binding, and effects on biofilm were evaluated by microdilution techniques. We also evaluated the interactions between (+)-ß-pinene and cell wall and membrane enzymes of interest. RESULTS: The MIC values of (+)-ß-pinene ranged from <56.25 to 1800 µmol/L. The MIC of (+)-ß-pinene did not increase when ergosterol was added to the medium, however it did increase in the presence of sorbitol, leading to a doubled MIC for C. tropicalis and C. krusei. The results of the molecular docking simulations indicated better interaction with delta-14-sterol reductase (-51 kcal/mol). (+)-ß-pinene presents anti-biofilm activity against multiples species of Candida. CONCLUSION: (+)-ß-pinene has antifungal activity and most likely acts through interference with the cell wall; through molecular interaction with Delta-14-sterol reductase and, to a lesser extent, with the 1,3-ß- glucan synthase. This molecule was also found to effectively reduce Candida biofilm adhesion.
Subject(s)
Antifungal Agents/pharmacology , Bridged Bicyclo Compounds/pharmacology , Candida/drug effects , Monoterpenes/pharmacology , Antifungal Agents/chemistry , Bicyclic Monoterpenes , Biofilms/drug effects , Bridged Bicyclo Compounds/chemistry , Microbial Sensitivity Tests , Molecular Docking Simulation , Monoterpenes/chemistry , StereoisomerismABSTRACT
This paper provides a comparative account of the essential oil chemical composition and biological activities of five Brazilian species of Baccharis (Asteraceae), namely B. microdonta, B. pauciflosculosa, B. punctulata, B. reticularioides, and B. sphenophylla. The chemical compositions of three species (B. pauciflosculosa, B. reticularioides, and B. sphenophylla) are reported for the first time. Analyses by GC/MS showed notable differences in the essential oil compositions of the five species. α-Pinene was observed in the highest concentration (24.50%) in B. reticularioides. Other major compounds included α-bisabolol (23.63%) in B. punctulata, spathulenol (24.74%) and kongol (22.22%) in B. microdonta, ß-pinene (18.33%) and limonene (18.77%) in B. pauciflosculosa, and ß-pinene (15.24%), limonene (14.33%), and spathulenol (13.15%) in B. sphenophylla. In vitro analyses for antimalarial, antitrypanosomal, and insecticidal activities were conducted for all of the species. B. microdonta and B. reticularioides showed good antitrypanosomal activities; B. sphenophylla showed insecticidal activities in fumigation bioassay against bed bugs; and B. pauciflosculosa, B. reticularioides, and B. sphenophylla exhibited moderate antimalarial activities. B. microdonta and B. punctulata showed cytotoxicity. The leaves and stems of all five species showed glandular trichomes and ducts as secretory structures. DNA barcoding successfully determined the main DNA sequences of the investigated species and enabled authenticating them.
Subject(s)
Antimalarials/chemistry , Baccharis/classification , Insecticides/chemistry , Oils, Volatile/chemistry , Trypanocidal Agents/chemistry , Animals , Antimalarials/pharmacology , Baccharis/chemistry , Baccharis/genetics , Bedbugs/drug effects , Bicyclic Monoterpenes , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/pharmacology , DNA Barcoding, Taxonomic , Gas Chromatography-Mass Spectrometry , Insecticides/pharmacology , Limonene/chemistry , Limonene/pharmacology , Monocyclic Sesquiterpenes , Monoterpenes/chemistry , Monoterpenes/pharmacology , Oils, Volatile/pharmacology , Plant Leaves/chemistry , Plant Oils/chemistry , Plant Oils/pharmacology , Plant Stems/chemistry , Sesquiterpenes/chemistry , Sesquiterpenes/pharmacology , Trypanocidal Agents/pharmacologyABSTRACT
In this study, we aimed to determine whether seasonality affects the content, chemical composition, and antimicrobial activity of essential oils (EOs) from the leaves of three species of Nectandra (Nectandra megapotamica, Nectandra grandiflora, and Nectandra lanceolata) native to the Atlantic rainforest, Sao Paulo state, Brazil. In addition, we identified the compounds potentially related to the antimicrobial activity. Leaves were randomly collected in the middle of winter (August), spring (November), summer (February), and autumn (May). The influence of seasonality on the content and chemical composition of EOs from the Nectandra species was evident in this study. The EOs from N. lanceolata and N. grandiflora were characterized by similarities in the chemical composition and had a higher relative proportion of oxygenated sesquiterpenes. N. megapotamica presented a different chemical profile, with plenty of monoterpenic and sesquiterpenic hydrocarbons. Changes in the EO chemical profile because of seasonality were shown by the similarities between the EOs obtained in spring and autumn and the differences between the EOs obtained in summer and winter. The EO from the leaves of N. megapotamica harvested in winter and spring showed the highest control of the growth of Escherichia coli, and this antimicrobial action can be related to the monoterpenes α-pinene and ß-pinene as well as myrcene and limonene. The minimum inhibitory concentration (MIC) of the EO from the leaves of N. lanceolata harvested in summer and autumn was lower against the gram-positive bacterium Staphylococcus aureus and can be related to the sesquiterpene hydrocarbons isobicyclogermacrenal, epi-zizanone, and germacrene B.
Subject(s)
Anti-Infective Agents/chemistry , Lauraceae/chemistry , Oils, Volatile/chemistry , Sesquiterpenes/chemistry , Acyclic Monoterpenes , Aldehydes/chemistry , Alkenes/chemistry , Anti-Infective Agents/pharmacology , Bicyclic Monoterpenes , Brazil , Bridged Bicyclo Compounds/chemistry , Escherichia coli/drug effects , Escherichia coli/pathogenicity , Monoterpenes/chemistry , Oils, Volatile/pharmacology , Plant Leaves/chemistry , Seasons , Sesquiterpenes/pharmacology , Staphylococcus aureus/drug effects , Staphylococcus aureus/pathogenicityABSTRACT
DNA gyrases are enzymes that control the topology of DNA in bacteria cells. This is a vital function for bacteria. For this reason, DNA gyrases are targeted by widely used antibiotics such as quinolones. Recently, structural and biochemical investigations identified a new class of DNA gyrase inhibitors called NBTIs (i.e., novel bacterial topoisomerase inhibitors). NBTIs are particularly promising because they are active against multi-drug resistant bacteria, an alarming clinical issue. Structural data recently demonstrated that these NBTIs bind tightly to a newly identified pocket at the dimer interface of the DNA-protein complex. In the present study, we used molecular dynamics (MD) simulations and docking calculations to shed new light on the binding of NBTIs to this site. Interestingly, our MD simulations demonstrate the intrinsic flexibility of this binding site, which allows the pocket to adapt its conformation and form optimal interactions with the ligand. In particular, we examined two ligands, AM8085 and AM8191, which induced a repositioning of a key aspartate (Asp83B), whose side chain can rotate within the binding site. The conformational rearrangement of Asp83B allows the formation of a newly identified H-bond interaction with an NH on the bound NBTI, which seems important for the binding of NBTIs having such functionality. We validated these findings through docking calculations using an extended set of cognate oxabicyclooctane-linked NBTIs derivatives (~150, in total), screened against multiple target conformations. The newly identified H-bond interaction significantly improves the docking enrichment. These insights could be helpful for future virtual screening campaigns against DNA gyrase.
Subject(s)
Anti-Bacterial Agents/chemistry , Aspartic Acid/chemistry , Bridged Bicyclo Compounds/chemistry , DNA Gyrase/chemistry , Protein Subunits/chemistry , Staphylococcus aureus/chemistry , Topoisomerase Inhibitors/chemistry , Amino Acid Motifs , Anti-Bacterial Agents/metabolism , Aspartic Acid/metabolism , Binding Sites , Bridged Bicyclo Compounds/metabolism , DNA Gyrase/genetics , DNA Gyrase/metabolism , Escherichia coli/chemistry , Escherichia coli/enzymology , Gene Expression , Hydrogen Bonding , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Binding , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , Protein Multimerization , Protein Subunits/antagonists & inhibitors , Protein Subunits/genetics , Protein Subunits/metabolism , Staphylococcus aureus/enzymology , Topoisomerase Inhibitors/metabolismABSTRACT
The metal-organic framework [(La0.9 Sm0.1 )2 (DPA)3 (H2 O)3 ]∞ was synthetized and characterized by X-ray diffractometry, differential thermogravimetric analysis, and infrared spectroscopy. The material was tested for the development and validation of a matrix solid-phase dispersion procedure for extraction of atrazine, bifenthrin, bromuconazole, clofentezine, fenbuconazole, flumetralin, procymidone, and pirimicarb, from peppers, with analysis using gas chromatography with mass spectrometry in the selected ion monitoring mode. The method developed was linear over the range tested (50.0-1000.0 µg/kg for procymidone and 200.0-1000.0 µg/kg for all other pesticides), with correlation coefficients ranging from 0.9930 to 0.9992. Experiments were carried out at 250.0, 500.0, and 1000.0 µg/kg fortification levels, and resulted in recoveries in the range of 52.7-135.0%, with coefficient of variation values between 5.2 and 5.4%, respectively, for [(La0.9 Sm0.1 )2 (DPA)3 (H2 O)3 ]∞ sorbent. Detection and quantification limits ranged from 16.0 to 67.0 µg/kg and from 50.0 to 200.0 µg/kg, respectively, for the different pesticides studied. The results were compared with literature data. The developed and validated method was applied to real samples. The analysis detected the presence of residues of pesticides procymidone, fenbuconazole, flumetralin, clofentezine, atrazine, and bifenthrin.
Subject(s)
Capsicum/chemistry , Lanthanoid Series Elements/chemistry , Metal-Organic Frameworks/chemistry , Pesticides/isolation & purification , Solid Phase Extraction , Aniline Compounds/chemistry , Aniline Compounds/isolation & purification , Atrazine/chemistry , Atrazine/isolation & purification , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/isolation & purification , Carbamates/chemistry , Carbamates/isolation & purification , Chlorobenzenes/chemistry , Chlorobenzenes/isolation & purification , Furans/chemistry , Furans/isolation & purification , Gas Chromatography-Mass Spectrometry , Metal-Organic Frameworks/chemical synthesis , Nitriles/chemistry , Nitriles/isolation & purification , Pesticides/chemistry , Pyrethrins/chemistry , Pyrethrins/isolation & purification , Pyrimidines/chemistry , Pyrimidines/isolation & purification , Triazoles/chemistry , Triazoles/isolation & purificationABSTRACT
PDE3s belong to the phosphodiesterases family, where the PDE3A isoform is the major subtype in platelets involved in the cAMP regulation pathway of platelet aggregation. PDE3A inhibitors have been designed as potential antiplatelet agents. In this work, a homology model of PDE3A was developed and used to obtain the binding modes of bicyclic heteroaromatic pyridazinones and pyrazolones. Most of the studied compounds adopted similar orientations within the PDE3A active site, establishing hydrogen bonds with catalytic amino acids. Besides, the structure-activity relationship of the studied inhibitors was described by using a field-based 3D-QSAR method. Different structure alignment strategies were employed, including template-based and docking-based alignments. Adequate correlation models were obtained according to internal and external validations. In general, QSAR models revealed that steric and hydrophobic fields describe the different inhibitory activities of the compounds, where the hydrogen bond donor and acceptor fields have minor contributions. It should be stressed that structural elements of PDE3A inhibitors are reported here, through descriptions of their binding interactions and their differential affinities. In this sense, the present results could be useful in the future design of more specific and potent PDE3A inhibitors that may be used for the treatment of cardiovascular diseases.
Subject(s)
Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/pharmacology , Cyclic Nucleotide Phosphodiesterases, Type 3/drug effects , Phosphodiesterase 3 Inhibitors/pharmacology , Pyrazolones/chemistry , Pyrazolones/pharmacology , Pyridones/chemistry , Pyridones/pharmacology , Molecular Docking Simulation , Quantitative Structure-Activity RelationshipABSTRACT
Bicycloalkyl groups have been previously described as phenyl group bioisosteres. This article describes the synthesis of new building blocks allowing their introduction into complex molecules, and explores their use as a means to modify the physicochemical properties of drug candidates and improve the quality of imaging agents. In particular, the replacement of an aromatic ring with a bicyclo[1.1.1]pentane-1,3-diyl (BCP) group improves aqueous solubility by at least 50-fold, and markedly decreases nonspecific binding (NSB) as measured by CHI(IAM), the chromatographic hydrophobicity index on immobilized artificial membranes. Structural variations with the bicyclo[2.2.2]octane-1,4-diyl group led to more lipophilic molecules and did not show the same benefits regarding NSB or solubility, whereas substitutions with cubane-1,4-diyl showed improvements for both parameters. These results confirm the potential advantages of both BCP and cubane motifs as bioisosteric replacements for optimizing para-phenyl-substituted molecules.
Subject(s)
Bridged Bicyclo Compounds/chemistry , Membranes, Artificial , Aniline Compounds/chemistry , Bridged Bicyclo Compounds/chemical synthesis , Carboxylic Acids/chemistry , Hydrophobic and Hydrophilic Interactions , Ligands , SolubilityABSTRACT
The lesser mealworm, Alphitobius diaperinus Panzer 1797 (Coleoptera: Tenebrionidae), is a cosmopolitan insect pest affecting poultry production. Due to its cryptic behavior, insecticide control is usually not efficient. Thus, sustainable and effective methods would have an enormous and positive impact in poultry production. The aim of this study was to confirm the identity of the male-produced aggregation pheromone for a Brazilian population of A. diaperinus and to evaluate its biological activity in behavioral assays. Six male-specific compounds were identified: (R)-limonene (1), (E)-ocimene (2), 2-nonanone (3), (S)-linalool (4), (R)-daucene (5), all described before in an American population, and a sixth component, (E,E)-α-farnesene (6), which is apparently exclusive to a Brazilian population. Y-Tube bioassays confirmed the presence of a male-produced aggregation pheromone and showed that all components need to be present in a similar ratio and concentration as emitted by male A. diaperinus to produce a positive chemotactic response.
Subject(s)
Chemotaxis , Pheromones/chemistry , Tenebrio/drug effects , Acyclic Monoterpenes , Alkenes/chemistry , Animals , Behavior, Animal , Brazil , Bridged Bicyclo Compounds/chemistry , Chromatography, Gas , Cyclohexenes/chemistry , Female , Gas Chromatography-Mass Spectrometry , Ketones/chemistry , Limonene , Male , Monoterpenes/chemistry , Olfactometry , Sesquiterpenes/chemistry , Terpenes/chemistry , Volatile Organic Compounds/chemistryABSTRACT
A head space solid-phase microextraction method combined with gas chromatography-mass spectrometry was developed and optimised to extract and analyse volatile compounds of Melipona beecheii geopropolis. Seventy-three constituents were identified using this technique in the sample of geopropolis collected. The main compounds detected include ß-fenchene (14.53-15.45%), styrene (8.72-9.98%), benzaldehyde (7.44-7.82%) and the most relevant volatile components presents at high level in the geopropolis were terpenoids (58.17%).
Subject(s)
Gas Chromatography-Mass Spectrometry/methods , Propolis/analysis , Solid Phase Microextraction/methods , Volatile Organic Compounds/analysis , Animals , Bees , Benzaldehydes/analysis , Benzaldehydes/chemistry , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/isolation & purification , Camphanes , Mexico , Propolis/chemistry , Styrene/analysis , Styrene/chemistry , Terpenes/analysis , Volatile Organic Compounds/chemistryABSTRACT
CONTEXT: Nectandra (Lauraceae) species have been used in folk medicine as an antidiarrheal, analgesic, antifungal, etc., and have many pharmacological proprieties. OBJECTIVE: Investigation of the chemical composition and cytotoxicity of essential oil from Nectandra leucantha Nees & Mart. leaves. This is the first study involving N. leucantha reported in the literature. MATERIAL AND METHODS: The essential oil of N. leucantha leaves was obtained by hydrodistillation. Its chemical composition was determined using a combination of GC/FID, GC/MS, and determination of Kovats index (KI). In vitro cytotoxic activity was evaluated against six cancer cell lines - murine melanoma (B16F10-Nex2), human glioblastome (U-87), human cervical carcinoma (HeLa), human colon carcinoma (HCT), human breast adenocarcinoma (MCF7), and human cervical tumor (Siha) as well as against one non-tumorigenic cell line - human foreskin fibroblast (HFF). RESULTS: Thirty-three compounds were identified primarily sesquiterpenes (81.41%), the main compounds being bicyclogermacrene (28.44%), germacrene A (7.34%), spathulenol (5.82%), and globulol (5.25%). Furthermore, monoterpenes were also found in the analyzed oil (12.84%), predominantly α- and ß-pinenes (6.59 and 4.57%, respectively). The crude essential oil displayed significant cytotoxic activity against B16F10-Nex2 (IC50 33 ± 1 µg/mL) and U87 (IC50 75.95 ± 0.03 µg/mL) and HeLa (IC50 60 ± 12 µg/mL) cell lines. The main identified compound, bicyclogermacrene, displayed IC50 ranging from 3.1 ± 0.2 to 21 ± 6 µg/mL. DISCUSSION AND CONCLUSION: The results indicate that the crude oils from leaves of N. leucantha displayed cytotoxic activity being bicyclogermacrene, the main compound identified in the crude oil responsible, at least in part, for this potential.
Subject(s)
Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Lauraceae/chemistry , Oils, Volatile/chemistry , Oils, Volatile/pharmacology , Plant Oils/chemistry , Plant Oils/pharmacology , Animals , Antineoplastic Agents, Phytogenic/isolation & purification , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/isolation & purification , Bridged Bicyclo Compounds/pharmacology , Cell Line, Tumor , Cell Survival/drug effects , Humans , Mice , Molecular Structure , Oils, Volatile/isolation & purification , Plant Leaves/chemistry , Plant Oils/isolation & purification , Sesquiterpenes, Germacrane/chemistry , Sesquiterpenes, Germacrane/isolation & purification , Sesquiterpenes, Germacrane/pharmacologyABSTRACT
The essential oils from Mangifera indica var. Rosa and Espada latex were obtained by hydrodistillation and analyzed using GC-FID and GC-MS. Twenty-seven components were identified. The main compound in the essential oil from M. indica var. Espada (EOMiE) was terpinolene (73.6%). The essential oil of M. indica var. Rosa (EOMiR) was characterized by high amounts of ß-pinene (40.7%) and terpinolene (28.3%). In the test for leishmanicidal activity against promastigotes forms of L. amazonensis, EOMiR and EOMiE showed IC50 (72 h) of 39.1 and 23.0 µg/mL, respectively. In macrophages, EOMiR and EOMiE showed CC50 of 142.84 and 158.65 µg/mL, respectively. However, both were more specific to the parasite than macrophages, with values of selectivity index of 6.91 for EOMiE and 3.66 for EOMiR. The essential oils were evaluated for their cytotoxicity against the human tumor cells HEp-2, HT-29, NCI-H292, and HL-60. The EOMiR and EOMiE were most effective against the HL-60, with IC50 values of 12.3 and 3.6 µg/mL, respectively. The results demonstrated that the essential oils of M. indica can destroy L. amazonensis and inhibit tumor cell growth. These findings contribute to the knowledge of the Brazilian biodiversity as a source of potential therapeutic agents.
Subject(s)
Leishmania/drug effects , Mangifera/chemistry , Oils, Volatile/administration & dosage , Oils, Volatile/chemistry , Bicyclic Monoterpenes , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/isolation & purification , Cell Proliferation/drug effects , Cyclohexane Monoterpenes , HT29 Cells , Humans , Leishmaniasis/drug therapy , Leishmaniasis/pathology , Monoterpenes/chemistry , Monoterpenes/isolation & purification , Neoplasms/drug therapy , Neoplasms/pathology , Terpenes/chemistry , Terpenes/isolation & purificationABSTRACT
Clusianone is a member of the polycyclic polyprenylated acylphloroglucinol family of natural products; its cytotoxic mechanism is unknown. Clusianone is a structural isomer of nemorosone, which is a mitochondrial uncoupler and a well-known cytotoxic anti-cancer agent; thus, we addressed clusianone action at the mitochondria and its potential cytotoxic effects on cancer cells. In the HepG2 hepatocarcinoma cell line, clusianone induced mitochondrial membrane potential dissipation, ATP depletion and phosphatidyl serine externalization; this later event is indicative of apoptosis induction. In isolated mitochondria from rat liver, clusianone promoted protonophoric mitochondrial uncoupling. This was evidenced by the dissipation of mitochondrial membrane potential, an increase in resting respiration, an inhibition of Ca(2+) influx, stimulation of Ca(2+) efflux in Ca(2+)-loaded mitochondria, a decrease in ATP and NAD(P)H levels, generation of ROS, and swelling of valinomycin-treated organelles in hyposmotic potassium acetate media. The cytotoxic and uncoupling actions of clusianone were appreciably less than those of nemorosone, likely due to the presence of an intra-molecular hydrogen bond with the juxtaposed carbonyl group at the C15 position. Therefore, clusianone is capable of pharmacologically increasing the leakage of protons from the mitochondria and with favorable cytotoxicity in relation to nemorosone.
Subject(s)
Benzophenones/chemistry , Biological Products/chemistry , Biological Products/pharmacology , Bridged Bicyclo Compounds/pharmacology , Mitochondria, Liver/drug effects , Mitochondria, Liver/metabolism , Uncoupling Agents/chemistry , Adenosine Triphosphate/metabolism , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Benzophenones/pharmacology , Benzoquinones , Biological Transport/drug effects , Bridged Bicyclo Compounds/chemistry , Calcium/metabolism , Cell Death/drug effects , Cell Respiration/drug effects , Hep G2 Cells , Humans , Membrane Potential, Mitochondrial/drug effects , NAD/metabolism , Osmotic Pressure/drug effects , Rats , Reactive Oxygen Species/metabolism , Stereoisomerism , Structure-Activity Relationship , Uncoupling Agents/pharmacologyABSTRACT
Research has been conducted on the biotransformation of (8S,9R)-isocaryolan-9-ol (4a) and (1S,2S,5R,8S)-8-methylene-1,4,4-trimethyltricyclo[6.2.1.0(2,5)]undecan-12-ol (5a) by the fungal phytopathogen Botrytis cinerea. The biotransformation of compound 4a yielded compounds 6-9, while the biotransformation of compound 5a yielded compounds 10-13. The activity of compounds 4a and 5a against B. cinerea has been evaluated. (8R,9R)-Isocaryolane-8,9-diol (6), a major metabolite of compound 4a, shows activity compared to its parent compound 4a, which is inactive. The effect of isocaryolanes 3, 4a, and 5a, together with their biotransformation products 6-8, 10, and 14-17, on the germination and radicle and shoot growth of Lactuca sativa (lettuce) has also been determined. Compounds 7-13 are described for the first time.
Subject(s)
Botrytis/metabolism , Fungicides, Industrial/chemistry , Fungicides, Industrial/pharmacology , Sesquiterpenes/chemistry , Sesquiterpenes/pharmacology , Aldehydes/chemistry , Aldehydes/metabolism , Biotransformation , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/metabolism , Lactuca/growth & development , Lactuca/physiology , Molecular Structure , Stereoisomerism , Structure-Activity RelationshipABSTRACT
A method based on the differential reactivity of thiol and thiolate with monobromobimane (mBBr) has been developed to measure nucleophilicity and acidity of protein and low-molecular-weight thiols. Nucleophilicity of the thiolate is measured as the pH-independent second-order rate constant of its reaction with mBBr. The ionization constants of the thiols are obtained through the pH dependence of either second-order rate constant or initial rate of reaction. For readily available thiols, the apparent second-order rate constant is measured at different pHs and then plotted and fitted to an appropriate pH function describing the observed number of ionization equilibria. For less available thiols, such as protein thiols, the initial rate of reaction is determined in a wide range of pHs and fitted to the appropriate pH function. The method presented here shows excellent sensitivity, allowing the use of nanomolar concentrations of reagents. The method is suitable for scaling and high-throughput screening. Example determinations of nucleophilicity and pK(a) are presented for captopril and cysteine as low-molecular-weight thiols and for human peroxiredoxin 5 and Trypanosoma brucei monothiol glutaredoxin 1 as protein thiols.
Subject(s)
Bridged Bicyclo Compounds/chemistry , Sulfhydryl Compounds/chemistry , Cysteine/chemistry , Fluorescence , Glutaredoxins/chemistry , Humans , Hydrogen-Ion Concentration , Peroxiredoxins/chemistry , Trypanosoma brucei brucei/enzymologyABSTRACT
The structure of naturally-occurring cinerin C [systematic name: (7S,8R,3'R,4'S,5'R)-Δ(8')-4'-hydroxy-5,5',3'-trimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan], isolated from the ethanol extract of leaves of Pleurothyrium cinereum (Lauraceae), has previously been established by NMR and HRMS spectroscopy, and its absolute configuration established by circular dichroism measurements. For the first time, its crystal structure has now been established by single-crystal X-ray analysis, as the monohydrate, C(22)H(26)O(7)·H(2)O. The bicyclooctane moiety comprises fused cyclopentane and cyclohexenone rings which are almost coplanar. An intermolecular O-H···O hydrogen bond links the 4'-OH and 5'-OCH(3) groups along the c axis.
Subject(s)
Bridged Bicyclo Compounds/chemistry , Lauraceae/chemistry , Lignans/chemistry , Plant Leaves/chemistry , Bridged Bicyclo Compounds/isolation & purification , Circular Dichroism , Crystallography, X-Ray , Lignans/isolation & purification , Magnetic Resonance Spectroscopy , Molecular Structure , StereoisomerismABSTRACT
Plants are promising sources of new bioactive compounds. The aim of this study was to investigate the cytotoxic potential of nine plants found in Brazil. The species studied were: Annona pickelii Diels (Annonaceae), Annona salzmannii A. DC. (Annonaceae), Guatteria blepharophylla Mart. (Annonaceae), Guatteria hispida (R.âE. Fr.) Erkens & Maas (Annonaceae), Hancornia speciosa Gomes (Apocynaceae), Jatropha curcas L. (Euphorbiaceae), Kielmeyera rugosa Choisy (Clusiaceae), Lippia gracilis Schauer (Verbenaceae), and Hyptis calida Mart. Ex Benth (Lamiaceae). Different types of extractions from several parts of plants resulted in 43 extracts. Their cytotoxicity was tested against HCT-8 (colon carcinoma), MDA-MB-435 (melanoma), SF-295 (glioblastoma), and HL-60 (promielocitic leukemia) human tumor cell lines, using the thiazolyl blue test (MTT) assay. The active extracts were those obtained from G. blepharophylla, G. hispida, J. curcas, K. rugosa, and L. gracilis. In addition, seven compounds isolated from the active extracts were tested; among them, ß-pinene found in G. hispida and one coumarin isolated from K. rugora showed weak cytotoxic activity. In summary, this manuscript contributes to the understanding of the potentialities of Brazilian plants as sources of new anticancer drugs.
Subject(s)
Bridged Bicyclo Compounds/pharmacology , Coumarins/pharmacology , Magnoliopsida/chemistry , Monoterpenes/pharmacology , Oils, Volatile/pharmacology , Plant Extracts/pharmacology , Annonaceae/chemistry , Antineoplastic Agents, Phytogenic , Apocynaceae/chemistry , Bicyclic Monoterpenes , Brazil , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/isolation & purification , Cell Line, Tumor , Cell Survival , Clusiaceae/chemistry , Coumarins/chemistry , Coumarins/isolation & purification , Humans , Hyptis/chemistry , Jatropha/chemistry , Latex/chemistry , Lippia/chemistry , Monoterpenes/chemistry , Monoterpenes/isolation & purification , Oils, Volatile/chemistry , Oils, Volatile/isolation & purification , Plant Components, Aerial/chemistry , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plants, Medicinal/chemistryABSTRACT
The antimicrobial activities of the isomers and enantiomers of pinene were evaluated against bacterial and fungal cells. The agar diffusion test showed that only the positive enantiomers of the α- and ß-isomers of pinene were active. The minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MMC) of these monoterpenes were also determined, confirming that the positive enantiomers exhibited microbicidal activity against all fungi and bacteria tested with MICs ranging from 117 to 4,150 µg/mL. However, no antimicrobial activity was detected with the negative enantiomers up to 20 mg/mL. Time-kill curves showed that (+)-α-pinene and (+)-ß-pinene were highly toxic to Candida albicans, killing 100% of inoculum within 60 min. By contrast, the bactericidal effect occurred after 6 h in methicillin-resistant Staphylococcus aureus (MRSA). In combination with commercial antimicrobials, ciprofloxacin plus (+)-α-pinene or (+)-ß-pinene presented synergistic activity against MRSA whereas an indifferent effect against all fungi was detected when amphotericin B was combined with the positive enantiomers of pinene. The potential of (+)-α-pinene and (+)-ß-pinene to inhibit phospholipase and esterase activities was also evaluated, and the best inhibition results were obtained with Cryptococcus neoformans. C. albicans biofilm formation was prevented with the MIC concentration of (+)-α-pinene and twice the MIC value of (+)-ß-pinene. Finally, the cytotoxicity of the positive enantiomers of pinene to murine macrophages was evaluated, and 250 µg/mL of (+)-α-pinene and (+)-ß-pinene reduced the cell viability to 66.8% and 57.7%, respectively.
Subject(s)
Anti-Infective Agents/pharmacology , Bridged Bicyclo Compounds/pharmacology , Monoterpenes/pharmacology , Animals , Anti-Bacterial Agents/pharmacology , Anti-Infective Agents/chemistry , Antifungal Agents/pharmacology , Bacteria/drug effects , Bacteria/metabolism , Bicyclic Monoterpenes , Biofilms/drug effects , Bridged Bicyclo Compounds/chemistry , Drug Synergism , Esterases/antagonists & inhibitors , Fungi/drug effects , Fungi/metabolism , Macrophages/drug effects , Mice , Microbial Sensitivity Tests , Monoterpenes/chemistry , Phospholipases/antagonists & inhibitorsABSTRACT
This work reports isolation of an unusual lignan with a bicyclic [2.2.2] octene skeleton, named rufescenolide (1), from stems of Cordia rufescens, along with ß-sitosterol, stigmasterol, syringaldehyde, 3-ß-O-D-glucopyranosyl-sitosterol, methyl caffeate, 4-methoxy-protocatechuic acid and methyl rosmarinate. Structural characterizations employed IR spectroscopic, ESIHRMS and mono and dimensional NMR spectroscopy.
Subject(s)
Bridged Bicyclo Compounds/isolation & purification , Caffeic Acids/chemistry , Cordia/chemistry , Lignans/chemistry , Octanes/chemistry , Bridged Bicyclo Compounds/chemistry , Hydroxybenzoates/chemistry , Lignans/isolation & purification , Magnetic Resonance Spectroscopy , Molecular Structure , Octanes/isolation & purification , Plant Stems/chemistry , Sitosterols/chemistry , Sitosterols/isolation & purification , Stigmasterol/chemistry , Stigmasterol/isolation & purificationABSTRACT
The composition of three samples of essential oil (EO) extracted from the leaves and flowers of Hyptis fruticosa (Lamiaceae) were investigated by GC/MS and GC-FID. The variability of the constituents and biological activity were evaluated in the oil samples. Acetic acid-induced abdominal constrictions and formalin-induced pain tests in mice were used for screening the antinociceptive activity. The possible antagonism of the essential oils or morphine (MOR) antinociceptive effects by pretreatment with naloxone, showed no influence on the antinociceptive action of the oils in the acetic acid-induced writhing test. All examined oil samples presented antinociceptive activity. The oil sample obtained from the leaves collected during the vegetative growth stage, near São Cristóvão at Sítio Tujubeba exhibited the highest effect. The same oil sample had a main percentage of 1,8-cineole (18.70%). Nevertheless, the oil obtained from flowers collected at the same location, showed a significant difference (p < 0.05) in the response intensity in the first phase of paw licking (100 mg/kg) possibly due to the higher contents of α-pinene (20.51%) and ß-pinene (13.64%). The results provide evidence for the use of H. fruticosa by traditional medicine practitioners in the management of pain.
Subject(s)
Analgesics/pharmacology , Hyptis/chemistry , Nociception/drug effects , Oils, Volatile/pharmacology , Acetic Acid , Animals , Bicyclic Monoterpenes , Bridged Bicyclo Compounds/chemistry , Flowers/chemistry , Formaldehyde , Male , Mice , Monoterpenes/chemistry , Oils, Volatile/analysis , Plant Extracts/pharmacology , Plant Leaves/chemistryABSTRACT
The main objective of this work is to present the optimization of the biotransformation of R-(+)-limonene and (-)-ß-pinene aiming at the production of α-terpineol by strains of fungal and yeasts previously isolated by our research group using the methodology of experimental design. New optimized experimental data on α-terpineol production by the biotransformation of R-(+)-limonene and (-)-ß-pinene using newly isolated microorganisms are reported in this work. Conversion of about 1,700 mg/L was achieved when R-(+)-limonene was used as substrate and the newly isolated strain 05.01.35 as microorganism at the central point of the experimental design, corresponding to a substrate concentration of 1.75%, mass of inoculum of 2 g, and substrate to ethanol volume ratio of 1:1. The same experimental condition led to higher conversions when (-)-ß-pinene was used as substrates and the strains coded as 04.05.08 and 01.04.03 as microorganism. Here, conversions of about 770 mg/L were achieved.