Assuntos
Antibacterianos/biossíntese , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Macrolídeos , Micromonosporaceae , Família Multigênica/genética , Ácido 4-Aminobenzoico/antagonistas & inibidores , Antibacterianos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Macrolídeos/farmacologia , Micromonosporaceae/genética , Micromonosporaceae/metabolismoRESUMO
Investigation on the extracts of Hydnocarpus anthelminthica seeds led to the isolation of three new compounds, anthelminthicins A-C (1-3, resp.), and two known ones, namely chaulmoogric acid (4) and ethyl chaulmoograte (5). Their structures were determined mainly by using spectroscopic techniques. The absolute configuration at the cyclopentenyl moiety of compound 2 was rationalized by quantum calculations. Base hydrolysis, followed by optical-rotation comparison, allowed assignment of the configuration of chaulmoogric-acid moiety of compounds 3 and 5. Biological assays revealed that compounds 1-5 significantly inhibit Mycobacterium tuberculosis (MTB) growth with MIC values of 5.54, 16.70, 4.38, 9.82, and 16.80 microM, respectively. Compound 3 was found to inhibit the pathway between chorismate and para-aminobenzoic acid (pAba) with a MIC value of 11.3 microM, representing a new example of pAba inhibitor isolated from a natural source. All compounds were not toxic to Candida albicans SC5314 at a concentration up to 100 microM.
Assuntos
Ácido 4-Aminobenzoico/antagonistas & inibidores , Antituberculosos/química , Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Salicaceae/química , Sementes/química , Ácido 4-Aminobenzoico/química , Vias Biossintéticas/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Células Cultivadas , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Estrutura MolecularRESUMO
Several arylacridinyl sulfones have been synthesized and their antimalarial action was tested on Plasmodium falciparum. PABA (para-aminobenzoic acid) has no antagonistic effect with these compounds as opposed to the observed effect with dapsone and sulfonamides previously studied. A possible relationship between the ability of cleavage of the S-9C acridinic bond and activity is suggested.
Assuntos
Acridinas/farmacologia , Antimaláricos/farmacologia , Sulfonatos de Arila/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Ácido 4-Aminobenzoico/antagonistas & inibidores , Ácido 4-Aminobenzoico/farmacologia , Acridinas/síntese química , Animais , Antimaláricos/síntese química , Sulfonatos de Arila/síntese química , Dapsona/farmacologia , Estrutura Molecular , Testes de Sensibilidade Parasitária/estatística & dados numéricos , Relação Estrutura-Atividade , Sulfonamidas/farmacologiaRESUMO
A screening method was established to detect inhibitors of the biosynthetic pathways of aromatic amino acids and para-aminobenzoic acid, the precursor of folic acid, using an agar plate diffusion assay modified as an antagonism test. By this screening method, a family of three novel polycyclic polyketides named as abyssomicins was isolated from a marine strain of Verrucosispora. The main component abyssomicin C inhibits the pathway between chorismate and para-aminobenzoic acid and is strongly active against gram-positive bacteria, including multi-resistant clinical isolates of Staphylococcus aureus.
Assuntos
Ácido 4-Aminobenzoico/antagonistas & inibidores , Actinobacteria/metabolismo , Antibacterianos/isolamento & purificação , Macrolídeos/isolamento & purificação , Ácido 4-Aminobenzoico/metabolismo , Actinobacteria/química , Aminoácidos Aromáticos/antagonistas & inibidores , Aminoácidos Aromáticos/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Cromatografia Líquida de Alta Pressão , Fermentação , Sedimentos Geológicos/microbiologia , Macrolídeos/farmacologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , FilogeniaAssuntos
Ácido 4-Aminobenzoico/antagonistas & inibidores , Anti-Infecciosos/farmacologia , Di-Hidropteroato Sintase/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Sulfonamidas/farmacologia , Ácido 4-Aminobenzoico/farmacologia , Animais , Resistência a Medicamentos , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/crescimento & desenvolvimento , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/enzimologia , Plasmodium falciparum/crescimento & desenvolvimento , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Transaminases/antagonistas & inibidoresRESUMO
In air saturated suspensions of erythrocyte ghost membranes gamma-irradiation causes formation of lipid peroxides, measured as malonaldehyde, and a loss of membrane protein sulphydryl groups. Addition of N-(p-amino-benzoyl)-1-glutamate prevented peroxidation up to doses of 2 x 10(3) Gy, due to scavenging of hydroxyl radicals. Another hydroxyl scavenger sodium formate, also prevented peroxidation at low doses, but lost its protective effect at higher doses probably because of secondary reactions of the resulting superoxide radical anion. Two sulphur containing radioprotectants also were able to reduce the extent of lipid peroxidation. The enzymes catalase and superoxide dismutase were added to the irradiated suspensions in order to determine the contribution from hydrogen peroxide and superoxide to peroxidation. The extents of peroxidation are compared with structural modification of the membrane under the same conditions of irradiation.
Assuntos
Membrana Eritrocítica/efeitos da radiação , Eritrócitos/efeitos da radiação , Peróxidos Lipídicos/sangue , Ácido 4-Aminobenzoico/antagonistas & inibidores , Catalase , Membrana Eritrocítica/análise , Formiatos , Humanos , Iodoacetatos/farmacologia , Ácido Iodoacético , Peróxidos Lipídicos/efeitos da radiação , Protetores contra Radiação , Sódio , Superóxido DismutaseRESUMO
By CNDO (Complete Neglect of Differential Overlap) molecular orbital method, interatomic distances and XYZ cartesian corrdinates were calculated in five polymorphs (monohydrated, alpha, two beta, and gamma) of sulfanilamide. Interatomic distances thus obtained are very close to those originally presented by Bells & Roblin and support the mechanism of action postulated long algo for sulfa drugs as being competitive antagonism with p-aminobenzoic acid.