ABSTRACT
This study evaluated the impact of pH [7.4 and 6.5], bovine serum albumin [BSA], and human serum albumin [HSA] on Curcumin activity against 2 reference, 1 clinical, and 10 environmental strains of Staphylococcus aureus [S. aureus]. Minimal inhibitory concentrations [MICs] of Curcumin against S. aureus were statistically indifferent [p>0.05] at pH7.4 and pH6.5. Activity of Curcumin against S. aureus was reduced by two folds in the presence of 1.25-5% BSA/HAS
ABSTRACT
Antibacterial effect is one of the major therapeutic activities of plant-derived Curcumin. This work evaluated the effect of serum albumin, human plasma, and whole blood on the in vitro activity of Curcumin against eight clinical bacterial isolates by standard broth micro dilution and plate-counting methods. Toxicological effects of Curcumin towards human red blood cells [RBCs] and peripheral blood mononuclear cells [PBMCs] were also investigated. Curcumin exhibited weak activity against gram-negative bacteria, except Escherichia coli and Shigella flexneri were susceptible and was most active against gram-positive bacteria: Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis. The antibacterial activity was impaired in the presence of bovine serum albumin [BSA], human plasma and whole blood. Curcumin was not toxic to PBMCs and RBCs at 200micro g/mL. Furthermore, Curcumin showed synergistic activity in combination with antibiotics: Ciprofloxacin, Gentamicin, Vancomycin and Amikacin against Staphylococcus aureus. This study demonstrated that the interaction of Curcumin with plasma proteins diminishes its in vitro antibacterial activity. Curcumin derivatives with reduced affinity for plasma protein may improve the bioavailability and antibacterial activities
ABSTRACT
Peptides derived from HIV-1 transmembrane proteins have been extensively studied for antimicrobial activities, and they are known as antimicrobial peptides [AMPs]. These AMPs have also been reported to potently combat the drug-resistant microbes. In this study, we demonstrated that peptide no. 6383 originated from HIV-1 MN strain membrane-spanning domain of gp41 was active [2-log reductions] at 100 micro g/mL [56.5 micro M] against methicillin-resistant Staphylococcus aureus [MRSA] in 10% and 50% human plasma-supplemented phosphate buffered saline [PBS]. The activity was further enhanced [3-log reductions] in the presence of 5% human serum albumin [HSA] alone. All bactericidal activities were achieved within 6 hours. At 100 micro g/mL, the peptide showed only 13% toxicity against human erythrocytes. This peptide can serve as an attractive template for a design of a novel peptide antibiotic against drugresistant bacteria. By sequence-specific engineering or modifications, we anticipated that the bactericidal activity and the reduced toxicity against human erythrocytes will be improved
ABSTRACT
This study evaluated the synergistic antibacterial activity of Curcumin with 8 different antibiotic groups. Two reference, one clinical and ten environmental strains of Staphylococcus aureus [S. aureus] were tested. Disc diffusion assay with 25[micro]g/mL Curcumin demonstrated synergism in combination with a majority of tested antibiotics against S. aureus. However, checkerboard micro dilution assay only showed synergism, fractional inhibitory concentration index [FICI] <0.5 in three antibiotics i.e. Gentamicin, Amikacin, and Ciprofloxacin. Other antibiotics showed indifferent interactions but no antagonism was observed. In time-kill curve, appreciable reduction of bacterial cells was also observed in combination therapy [Curcumin + antibiotics] compared to monotherapy [Curcumin or antibiotic[s] alone]. The antibiotics with higher synergistic interaction with Curcumin are arranged in a decreasing order: Amikacin > Gentamicin > Ciprofloxacin