Antimicrobial potential of actinobacteria isolated from the rhizosphere of the Caatinga biome plant Caesalpinia pyramidalis Tul.

Actinobacteria are known to produce various secondary metabolites having antibiotic effects. This study assessed the antimicrobial potential of actinobacteria isolated from the rhizosphere of Caesalpinia pyramidalis Tul. from the Caatinga biome. Sixty-eight actinobacteria isolates were evaluated for antimicrobial activity against different microorganisms by disk diffusion and submerged fermentation, using different culture media, followed by determination of minimum inhibitory concentration (MIC) and chemical prospecting of the crude extract. Of the isolates studied, 52.9% of those isolated at 37°C and 47.05% of those isolated at 45°C had activity against Bacillus subtilis, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Fusarium moniliforme, and Candida albicans. When compared with others actinobacteria, the isolate C1.129 stood out with better activity and was identified by 16S rDNA gene analysis as Streptomyces parvulus. The crude ethanol extract showed an MIC of 0.97 µg/mL for MRSA and B. subtilis, while the ethyl acetate extract showed MIC of 3.9 µg/mL for S. aureus and MRSA, showing the greatest potential among the metabolites produced. Chemical prospecting revealed the presence of mono/sesquiterpenes, proanthocyanidin, triterpenes, and steroids in both crude extracts. This study evaluates S. parvulus activity against multi-resistant microorganisms such as MRSA. Thus, it proves that low-fertility soil, as is found in the Caatinga, may contain important microorganisms for the development of new antimicrobial drugs.

Antimicrobial activity of prodigiosin isolated from Serratia marcescens UFPEDA 398.

Prodigiosin is an alkaloid and natural red pigment produced by Serratia marcescens. Prodigiosin has antimicrobial, antimalarial and antitumor properties and induces apoptosis in T and B lymphocytes. These properties have piqued the interest of researchers in the fields of medicine, pharmaceutics and different industries. The aim of the present study was to evaluate the antimicrobial activity of prodigiosin against pathogenic micro-organisms. The red pigments produced by S. marcescens exhibited absorption at 534 nm, Rf of 0.59 and molecular weight of 323 m/z. Antimicrobial activity was tested against oxacillin-resistant Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes, Acinetobacter sp. and oxacillin-resistant S. aureus. The standard antibiotics employed were ampicillin, chloramphenicol, gentamicin and oxacillin. The disc-diffusion tests demonstrated significant inhibition zones for S. aureus (35 ± 0.6), E. faecalis (22 ± 1.0) and S. pyogenes (14 ± 0.6). However, prodigiosin showed resistance to E. coli, P. aeruginosa and acinetobacter, where no significant formation of inhibitory halos were observed. We determined the inhibitory minimum concentrations and bactericidal for 20 strains of oxacillin-resistant S. aureus (ORSA). The pattern was the antibiotic oxacillin. The minimum inhibitory concentrations observed ranged from 1, 2 and 4.0 µg/mL, respectively, while the minimum bactericidal concentrations ranged from 2, 4, 8 and 16 µg/mL. The S. marcescens prodigiosin produced by showed bactericidal and bacteriostatic effect showing promising antimicrobial activity and suggesting future studies regarding its applicability in antibiotics therapies directed ORSA.

Avaliação biológica de Foeniculum vulgare (Mill. ) (Umbelliferae/Apiaceae) / Biological evaluation of Foeniculum vulgare (Mill. ) (Umbelliferae/Apiaceae)

Foeniculum vulgare Mill. é espécie herbácea da família Umbelliferae, nativa da região do Mediterrâneo e da Ásia Menor, amplamente distribuída em todo o território brasileiro. É conhecida popularmente como funcho ou erva-doce e usada na medicina como analgésico, digestivo, carminativo, diurético, expectorante, lactígeno, anti-inflamatório, e antiespasmódico. O extrato bruto etanólico para a verificação das atividades biológicas foi preparado a partir de sementes compradas no comércio. Para a realização do perfil fitoquímico foi utilizada a cromatografia em camada delgada analítica; a atividade antimicrobiana foi determinada pelo teste de difusão em disco de papel e da concentração inibitória mínima (CIM); a atividade antinociceptiva foi realizada pelo método de contorções abdominais em cobaias. Os micro-organismos testados foram isolados clínicos multirresistentes obtidos do Setor de Bacteriologia do Hospital das Clínicas de Pernambuco. O estudo fitoquímico identificou a maioria dos compostos secundários presentes na fração metanólica das sementes, sendo eles: triterpenos, glicosídeos de flavanóides, terpenos menores (monoterpenóides, sesquiterpenóide e diterpenóides), e açúcares redutores. Os resultados obtidos mostraram que o extrato etanólico apresentou maior atividade frente à Micrococcus spp. (CIM=250µg/mL). Os resultados da avaliação da atividade antinociceptiva demonstraram que apenas a dosagem de 298 mg/Kg quando comparado com o padrão indometacina conseguiu uma redução significativa no número de contorções abdominais dos animais. Estudos posteriores deverão ser realizados para a identificação e isolamento de alguns compostos secundários, bem como a realização de outros protocolos de analgesia.

Foeniculum vulgare Mill. (Umbelliferae) is a herbaceous plant of the family Umbelliferae, native to the Mediterranean and Asia Minor region and widely distributed all over the Brazilian territory. It is commonly known as fennel or "erva-doce" and has been used in medicine as analgesic, digestive, carminative, diuretic, expectorant, lactigenous, anti-inflammatory, and antispasmodic agent. Crude ethanolic extract for the verification of biological activities was prepared from seeds bought in the market. For the phytochemical profile, analytical thin-layer chromatography was used; the antimicrobial activity was determined by the paper disc diffusion test and minimum inhibitory concentration (MIC); the antinociceptive activity was verified by the method of abdominal writhings in the animals. The tested microorganisms were multiresistant clinical isolates obtained from the Bacteriology Sector of the Clinical Hospital of Pernambuco. The phytochemical study identified the majority of secondary compounds present in the methanolic fraction of seeds, as follows: triterpenes, flavanoid glycosides, smaller terpenes (monoterpenoids, sesquiterpenoids and diterpenoids) and reducing sugars. The obtained results showed that the ethanolic extract had greater activity against Micrococcus spp. (MIC=250µg/mL). Results of the evaluation of the antinociceptive activity demonstrated that only the dosage of 298 mg/Kg, compared to the indomethacin pattern, led to a significant reduction in the number of abdominal writhings in the animals. Further studies will be carried out for the identification and isolation of some secondary compounds, as well as other analgesic protocols.