Abstract: The objective of this research was focused on investigating in vitro antimicrobial activity of Phellinus linteus fruiting body extracts on Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus. Phellinus linteus fruiting body was extracted with ethanol and ethyl acetate and was vaporized. The disc diffusion assay was used to assess antimicrobial activity against tested bacterial strains. Primary screening of chemical profile of crude extract was determined by using thin layer chromatography. The positive control and the negative control were used as erythromycin and dimethyl sulfoxide, respectively. Initial screening of Phellinus linteus crude extract with the disc diffusion assay demonstrated that only ethanol had greater antimicrobial activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus. The MIC assay showed that the lower MIC was observed with 0.5 mg/ml of Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus and 0.25 mg/ml. of Escherichia coli and Staphylococcus aureus, respectively. TLC chemical profile of extract was represented at Rf ≈ 0.71-0.76.
Abstract: For centuries humans have used the antimicrobial
properties of copper to their advantage. Yet, after all these years the
underlying mechanisms of copper mediated cell death in various
microbes remain unclear. We had explored the hypothesis that copper
mediated increased levels of lipid peroxidation in the membrane fatty
acids is responsible for increased killing in Escherichia coli. In this
study we show that in both gram positive (Staphylococcus aureus)
and gram negative (Pseudomonas aeruginosa) bacteria there is a
strong correlation between copper mediated cell death and increased
levels of lipid peroxidation. Interestingly, the non-spore forming
gram positive bacteria as well as gram negative bacteria show similar
patterns of cell death, increased levels of lipid peroxidation, as well
as genomic DNA degradation, however there is some difference in
loss in membrane integrity upon exposure to copper alloy surface.
Abstract: Antibacterial activity of Plumeria alba (Frangipani)
petals methanolic extracts were evaluated against Escherichia coli,
Proteus vulgaris,Staphylococcus aureus, Klebsiella pneumoniae,
Pseudomonas aeruginosa, Staphylococcus saprophyticus,
Enterococcus faecalis and Serratia marcescens by using disk
diffusion method. Concentration extracts (80 %) showed the highest
inhibition zone towards Escherichia coli (14.3 mm). Frangipani
extract also showed high antibacterial activity against
Staphylococcus saprophyticus, Proteus vulgaris and Serratia
marcescens, but not more than the zones of the positive control used.
Comparison between two broad specrum antibiotics to frangipani
extracts showed that the 80 % concentration extracts produce the
same zone of inhibition as Streptomycin. Frangipani extracts showed
no bacterial activity towards Klebsiella pneumoniae, Pseudomonas
aeruginosa and Enterococcus faecalis. There are differences in the
sensitivity of different bacteria to frangipani extracts, suggesting that
frangipani-s potency varies between these bacteria. The present
results indicate that frangipani showed significant antibacterial
activity especially to Escherichia coli.
Abstract: The present study has been taken to explore the
screening of in vitro antimicrobial activities of D-galactose-binding
sponge lectin (HOL-30). HOL-30 was purified from the marine
demosponge Halichondria okadai by affinity chromatography. The
molecular mass of the lectin was determined to be 30 kDa with a
single polypeptide by SDS-PAGE under non-reducing and reducing
conditions. HOL-30 agglutinated trypsinized and glutaraldehydefixed
rabbit and human erythrocytes with preference for type O
erythrocytes. The lectin was subjected to evaluation for inhibition of
microbial growth by the disc diffusion method against eleven human
pathogenic gram-positive and gram-negative bacteria. The lectin
exhibited strong antibacterial activity against gram-positive bacteria,
such as Bacillus megaterium and Bacillus subtilis. However, it did
not affect against gram-negative bacteria such as Salmonella typhi
and Escherichia coli. The largest zone of inhibition was recorded of
Bacillus megaterium (12 in diameter) and Bacillus subtilis (10 mm in
diameter) at a concentration of the lectin (250 μg/disc). On the other
hand, the antifungal activity of the lectin was investigated against six
phytopathogenic fungi based on food poisoning technique. The lectin
has shown maximum inhibition (22.83%) of mycelial growth of
Botrydiplodia theobromae at a concentration of 100 μg/mL media.
These findings indicate that the lectin may be of importance to
clinical microbiology and have therapeutic applications.