Effects of associations of tannins from Anacardium occidentale and Anadenanthera colubrina with cephalosporin against bovine Staphylococcus aureus isolates

ABSTRACT: The association of natural compounds isolated from medicinal plants with conventional antibiotics, both with similar mechanisms of action, have become a viable alternative strategy to overcome the problem of drug resistance. This study aimed to evaluate the in vitro antimicrobial activity of tannic substances present in the bark of Anacardium occidentale and Anadenanthera colubrina against samples of Staphylococcus aureus when in combination with cephalexin. These combinations were evaluated by determining the minimum inhibitory concentration (MIC). For this purpose, tannins and cephalexin were serially dissolved in distilled water at concentrations ranging from 0.976 mg/mL to 500 mg/mL and 2 mg/mL to 512 mg/mL, respectively. When combined, the compounds inhibited S. aureus growth forming halos ranging from 0.9 to 46 mm with an MIC of 7.8 mg/mL (tannins) and 4 µg/mL (cephalexin). The resulting effect of the combination of natural and synthetic substances with similar mechanisms of action presented better results than when tested alone. Thus, the conclusion is that both the tannins and cephalexin had their antimicrobial action enhanced when used in combination, enabling the use of lower concentrations while maintaining their antibacterial effect against strains of S. aureus

Immunocompetent host develops mild intestinal inflammation in acute infection with <i>Toxoplasma gondii</i> - Fig 5

<p>Myeloperoxidase activity in duodenum (A), jejunum (B) and ileum (C) and nitrite dosage as an indirect way to measure nitric oxide in the duodenum (D), jejunum (E) and ileum (F) at different times of early infection with oocysts of <i>T</i>. <i>gondii</i>. Data are mean ± S.E.M., * <i>p</i> < 0.05, compared to the control group (ANOVA, Tukey’s test). CG (Control group), G6, G12, G24 G48 and G72 (rats infected for 6, 12, 24, 48 or 72 hours with oocysts of ME 49 strain of <i>T</i>. <i>gondii</i>, respectively).</p

Representative photomicrographs of rat mesenteric microcirculation.

<p>CG (Control group), G6, G12 and G24 (infected for 6, 12 and 24 hours with oocysts of ME 49 strain of <i>T</i>. <i>gondii</i>). Increased number of rolling leukocytes was observed in the G6 and G12 and number of adherent in G24 in comparison with CG. Leukocytes (arrow). Final magnification: 3400x.</p

Representative photomicrograph and graphs for immunohistochemical evaluation of the expression of ICAM-1, PECAM-1 and P-selectin molecules on the mesenteric vascular endothelium of rats orally infected with <i>T</i>. <i>gondii</i> oocysts (ME49).

<p>Data are mean ± S.E.M. * <i>p</i> < 0.05, compared to the control group (ANOVA, Tukey’s test). CG (Control group), G6, G12, G24 G48 and G72 (rats infected for 6, 12, 24, 48 or 72 hours with oocysts of ME 49 strain of <i>T</i>. <i>gondii</i>, respectively).</p

Real-time quantitative PCR assay in the small intestine of <i>T</i>. <i>gondii</i> infected rats.

<p>Real-time quantitative PCR assay in the small intestine of <i>T</i>. <i>gondii</i> infected rats.</p