ABSTRACT
Objective: The objective of the current study was to compare the phytochemical composition and to evaluate the antibacterial properties of Cissus qudrangularis, Cinnamomum zeylanicum and Trigonella foenum-graecum against the bacterial strains Escherichia coli and Bacillus circulans. Methods: Qualitative analysis and quantitative estimation of various phytochemical components were done using standard protocols. Antibacterial activity against gram-negative Escherichia coli and gram-positive Bacillus circulans was evaluated using standard protocol of agar well diffusion and disc diffusion assay. The zone of inhibition was calculated. Results: Preliminary phytochemical analysis showed the presence of alkaloids, saponins and tannins in all three plant extracts. In quantitative estimation, Cinnamomum zeylanicum showed high alkaloid content (22%), Cissus qudrangularis showed high saponin content (6%) Trigonella foenum-graecum showed a high concentration (4.65 mg/g) of tannin. All the three plants showed moderate antimicrobial activity. The water extract of Cinnamomum zeylanicum showed the highest zone of inhibition (13 mm) against Escherichia coli and the water extract of Trigonella foenum-graecum showed the highest zone of inhibition (11 mm) against Bacillus circulans. Conclusion: The result of this study supports the use of all the selected three medicinal plants as a source of antibacterial substance for the possible treatment of human pathogenic organisms. These plants can be further subjected to isolation of the therapeutic phytochemicals and further pharmacological evaluation.
ABSTRACT
Abstract Bacteriocins are peptides produced by various species of bacteria, especially lactic acid bacteria, which exhibit a large spectrum of action against spoilage bacteria and foodborne pathogens. Successful application of techniques for quantitative or qualitative bacteriocin determination relies not only on the sensitivity of the test-microorganisms, but also on the agar-medium employed. Cell free supernatants are routinely used to preliminary screen for antimicrobial activity of bacteria by means of the agar well diffusion method, but the supernatant may also include other molecules (such as medium components and/or intracellular compounds) accidentally released during cell free supernatant preparation, which may interfere with the assay. Reproducibility of bacteriocin activity against the same test-microorganisms is an important factor to be considered. Unfortunately, no specific information about bioassays standardization to determine bacteriocin activity is available in the literature. In this work, growth inhibition by means of the agar well diffusion assays were carried out on different agar-media showing a strong dependence on the agar-medium used, indicating that the inhibitory effects could also depend on the diffusion of exudates that are included in the cell-free supernatant. The results presented in this communication show that selection of the agar-medium is crucial for the bioassay response.
Subject(s)
Bacteriocins/analysis , Agar/analysis , Agar/pharmacokineticsABSTRACT
OBJECTIVE@#To characterize the bacteriocin-like inhibitory-substances (BLIS) activity of Streptococcus macedonicus MBF10-2 [named BLIS(MBF10-2)], a bacteriocinogenic strain isolated from an Indonesian tofu byproduct.@*METHODS@#BLIS(MBF10-2) was obtained by culturing the bacterium, and standard deferred antagonism assays were used to demonstrate its activity. The antibacterial testing of fractions collected by filtration using 3-30 kDa cut-off membrane sizes were carried out by performing well diffusion method.@*RESULTS@#The growth of Micrococcus luteus, Streptococcus pyogenes, Lactococcus lactis, Leuconostoc mesenteroides and Weissella confusa were inhibited by BLIS(MBF10-2). Interestingly, BLIS-containing fractions obtained from sequential application on ultrafiltration membranes indicated that this bacterium Streptococcus macedonicus MBF10-2 could produces at least two antimicrobial peptides activities, one of which is likely to be a lantibiotic peptide. Potential synergistic activity against certain Gram-positive (but not Gram-negative) species when partnered with antibiotics (ampicillin, tetracycline or kanamycin) were observed.@*CONCLUSION@#Combination of some BLIS(MBF10-2) active fractions with antibiotics (ampicillin, tetracycline or kanamycin) could demonstrate synergistic activities against certain Gram-positive species.
ABSTRACT
Objective To characterize the bacteriocin-like inhibitory-substances (BLIS) activity of Streptococcus macedonicus MBF10-2 [named BLIS(MBF10-2)], a bacteriocinogenic strain isolated from an Indonesian tofu byproduct. Methods BLIS(MBF10-2) was obtained by culturing the bacterium, and standard deferred antagonism assays were used to demonstrate its activity. The antibacterial testing of fractions collected by filtration using 3–30 kDa cut-off membrane sizes were carried out by performing well diffusion method. Results The growth of Micrococcus luteus, Streptococcus pyogenes, Lactococcus lactis, Leuconostoc mesenteroides and Weissella confusa were inhibited by BLIS(MBF10-2). Interestingly, BLIS-containing fractions obtained from sequential application on ultrafiltration membranes indicated that this bacterium Streptococcus macedonicus MBF10-2 could produces at least two antimicrobial peptides activities, one of which is likely to be a lantibiotic peptide. Potential synergistic activity against certain Gram-positive (but not Gram-negative) species when partnered with antibiotics (ampicillin, tetracycline or kanamycin) were observed. Conclusion Combination of some BLIS(MBF10-2) active fractions with antibiotics (ampicillin, tetracycline or kanamycin) could demonstrate synergistic activities against certain Gram-positive species.
ABSTRACT
The aim of the present study was to isolate and study about the antibacterial activity of astaxanthin from marine yeast. Astaxanthin a carotenoid present in marine yeast and crustaceans posses a wide range of pharmacological activity. Yeast strain was isolated from the marine sediments collected from Cochin, Kerala during the month of August 2012. The samples were collected in sterile plastic covers and brought to the laboratory without exposing to the external environment further. The marine sediment samples were directly inoculated in yeast malt. After effective screening the strains containing astaxanthin was refrigerated for further use. The strains were purified by TLC using petroleum hexane: acetone (3:1). A spectrophotometric assay was carried out by measuring absorbance at 200-500nm. The antibacterial activity was studied on several organisms like Bacillus Subtilis, Salmonella typhi, Staphylococcus aureus and Pseudomonas aeroginosa. The extracts showed excellent antibacterial activity than the standard chloramphenicol. Among this, Pseudomonas aeroginasa showed maximum inhibition.
ABSTRACT
The aim of the present study was to isolate and study about the antibacterial activity of astaxanthin from marine yeast. Astaxanthin a carotenoid present in marine yeast and crustaceans posses a wide range of pharmacological activity. Yeast strain was isolated from the marine sediments collected from Cochin, Kerala during the month of August 2012. The samples were collected in sterile plastic covers and brought to the laboratory without exposing to the external environment further. The marine sediment samples were directly inoculated in yeast malt. After effective screening the strains containing astaxanthin was refrigerated for further use. The strains were purified by TLC using petroleum hexane: acetone (3:1). A spectrophotometric assay was carried out by measuring absorbance at 200-500nm. The antibacterial activity was studied on several organisms like Bacillus Subtilis, Salmonella typhi, Staphylococcus aureus and Pseudomonas aeroginosa. The extracts showed excellent antibacterial activity than the standard chloramphenicol. Among this, Pseudomonas aeroginasa showed maximum inhibition.
ABSTRACT
On a global scale, people have used plants to treat diseases and infections, and this has raised interest on the plant biodiversity potencial in the search of antimicrobial principles. In this work, 75 crude n-hexanes, dichloromethane and methanol extracts from the aerial parts of 25 plants belonging to four botanical families (Asteraceae, Euphorbiaceae, Rubiaceae and Solanaceae), collected at the Natural Regional Park Ucumari (Risaralda, Colombia), were evaluated for their antibacterial and antifungal activities by the agar well diffusion method. The antibacterial activities were assayed against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, and three Gram-negative ones named, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. In addition, the same plant extracts were tested against the yeast Candida albicans and the fungi Aspergillus fumigatus and Fusarium solani. Overall, the plant extracts examined displayed better bactericide rather than fungicide activities. In general, the best antibacterial activity was showed by the plant extracts from the Rubiaceae family, followed in order by the extracts from the Euphorbiaceae and Solanaceae ones. It is important to emphasize the great activity displayed by the methanol extract of Alchornea coelophylla (Euphorbiaceae) that inhibited four out of five bacteria tested (B. Subtilis, P. aeruginosa, S. aureus and E. coli). Furthermore, the best Minimal Inhibitory Concentration for the extracts with antifungal activities were displayed by the dichloromethane extracts from Acalypha diversifolia and Euphorbia sp (Euphorbiaceae). The most susceptible fungus evaluated was F. Solani since 60% and 20% of the dichloromethane and methanol extracts evaluated inhibited the growth of this phytopathogenic fungus. The antimicrobial activity of the different plant extracts examined in this work could be related to the secondary metabolites contents and their interaction and susceptibility of pathogenic microorganism evaluated.
Alrededor del mundo, la gente ha usado las plantas para tratar enfermedades e infecciones, este potencial ha hecho que se incremente el interés en la biodiversidad vegetal como fuente de principios antimicrobianos. En este trabajo, se evaluaron 75 extractos crudos de n-hexano, diclorometano y metanol, obtenidos a partir de la parte aérea de 25 especies de plantas proveniente de cuatro familias botánicas (Asteraceae, Euphorbiaceae, Rubiaceae y Solanaceae), colectadas en el Parque Regional Natural Ucumari (Risaralda, Colombia); los cuales fueron evaluados por sus actividades antibacteriana y antifúngica a través del método de difusión en pozo. La actividad antibacteriana fue ensayada frente a las bacterias Gram-positivas Staphylococcus aureus y Bacillus subtilis, y las g-negativas Klebsiella pneumoniae, Escherichia coli y Pseudomonas aeruginosa. Adicionalmente, las mismas plantas fueron evaluadas frente a la levadura Candida albicans y los hongos Aspergillus fumigatus y Fusarium solani. En general, las plantas ensayadas mostraron mejor actividad antibacteriana que antifúngica; donde la familia Rubiaceae fue la que presentó mayor actividad antibacteriana, seguida por las familias Euphorbiaceae y Solanaceae. El extracto metanólico de Alchornea coelophylla (Euphorbiaceae) fue el que presentó mejor actividad antibacteriana al inhibir cuatro de las bacteria ensayadas (B. Subtilis, P. aeruginosa, S. aureus y E. coli); y los extractos de diclorometano de Acalypha diversifolia y Euphorbia sp. (Euphorbiaceae) fueron los que tuvieron la menor Concentración Mínima Inhibitoria en la actividad antifúngica. El hongo evaluado más susceptible fue F. Solani, el cual fue inhibido por el 60% y el 20% de los extractos de diclorometano y metanol, respectivamente. Se considera que la actividad biológica de estos extractos, se relaciona con los metabolitos secundarios que ellos contienen y las diferentes susceptibilidades de los microorganismos patogénicos evaluados.