Natural cordiaquinones as strategies to inhibit the growth and biofilm formation of methicillin-sensitive and methicillin-resistant Staphylococcus spp

AIMS

The aim of this study was to investigate the antibacterial and antibiofilm potential of cordiaquinones B, E, L, N, and O against different Staphylococci strains, in addition to analyzing in silico the observed effect.

METHODS AND RESULTS

The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined according to CLSI guidelines. The inhibition of biofilm formation was investigated at sub-MICs. Atomic force microscopy (AFM) and density functional theory method were performed. The tested strains of Staphylococcus spp. were susceptible to cordiaquinones B, E, and L, among which cordiaquinone B exerted a bactericidal effect, confirmed by a bacterial growth curve study, against Staphylococcus saprophyticus. Cordiaquinones B and E showed lowest MBC values against S. saprophyticus. AFM revealed that cordiaquinone L reduced the mean cell size of S. saprophyticus. Cordiaquinones B and E inhibited the biofilm formation ability of S. aureus by ∼90%. The in silico analysis suggested that the antimicrobial activity of cordiaquinones is driven by their electron donation capability.

CONCLUSIONS

Cordiaquinones inhibit the growth and biofilm formation (virulence factor) of both methicillin-sensitive and methicillin-resistant Staphylococci strains, indicating their antimicrobial potential.

Theoretical UV-Vis spectra of tetracationic porphyrin: effects of environment on electronic spectral properties

Electronic and spectroscopic properties of tetracationic 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphyrin (TMPyP) were investigated in the framework of the density functional theory (DFT). Modeling of implicit solvent, charge effects, and medium acidity were performed and compared with experimental results. Various hybrid exchange correlation functionals in the Kohn-Sham Scheme of the DFT were employed and various porphyrin models were constructed, simulating different environmental conditions. Since porphyrins present several technological applications with a plethora of interacting systems and the optical spectra profiles are often used to characterize these macrocyclic compounds, the study performed here aims to stablish a correct description of the UV-Vis spectrum. These results allowed to reproduce, both qualitatively as well as quantitatively, the Soret band of the TMPyP.

Antifungal and anti-inflammatory potential of eschweilenol C-rich fraction derived from Terminalia fagifolia Mart

ETHNOPHARMACOLOGICAL RELEVANCE

Folk knowledge transmitted between generations allows traditional populations to maintain the use of medicinal plants for the treatment of several diseases. In this context, the species Terminalia fagifolia Mart., native to Brazil, is used for the treatment of chronic and infectious diseases. Plants rich in secondary metabolites, such as this species and their derivatives, may represent therapeutic alternatives for the treatment of diseases that reduce the quality of life of people.

AIM OF THE STUDY

The aim of this study was to evaluate the antifungal and anti-inflammatory potential of aqueous fraction from ethanolic extract of T. fagifolia, with in silico study of the major compound of the fraction.

MATERIAL AND METHODS

The phytochemical study of the aqueous fraction was performed by HPLC, LC/MS and NMR. The antifungal activity was evaluated against yeasts, by determination of the minimum inhibitory concentration and minimum fungicidal concentration. The effect on Candida albicans was analyzed by AFM. The antibiofilm potential against biofilms of C. albicans was also tested. The anti-inflammatory potential of the aqueous fraction was evaluated in vivo by the carrageenan-induced paw edema and peritonitis. A microglial model of LPS-induced neuroinflammation was also studied. Further insights on the activation mechanism were studied using quantum chemistry computer simulations. Toxicity was evaluated in the Galleria mellonella and human erythrocytes models.

RESULTS

Eschweilenol C was identified as the major constituent of the aqueous fraction of the ethanolic extract of T. fagifolia. The aqueous fraction was active against all Candida strains used (sensitive and resistant to Fluconazole) with MICs ranging from 1000 to 0.4 μg/mL. By AFM it was possible to observe morphological alterations in treated Candida cells. The fraction significantly (p < 0.05) inhibited paw edema and decreased levels of malondialdehyde induced by carrageenan. In a microglial cell model, aqueous fraction demonstrated the ability to inhibit NF-κB after induction with lipopolysaccharide. The theoretical studies showed structural similarity between eschweilenol C and indomethacin and an excellent antioxidant potential. The aqueous fraction did not present toxicity in the studied models.

CONCLUSION

The results indicate that the aqueous fraction of T. fagifolia has potential for biomedical applications with low toxicity. This finding can be attributed to the predominance of eschweilenol C in the aqueous fraction.