Staphylococcus aureus membrane-damaging activities of four phenolics

Use of a product based on wood vinegar of Eucalyptus clone I144 used in the control of bovine mastitis

Bovine mastitis is one of the most frequent diseases in dairy cattle worldwide. The use of antiseptics in milking, if properly used, can lead to a reduction in potentially pathogenic microorganisms and their transmission between herds. Several medicinal plants have antiseptic potential, including eucalyptus (Eucalyptus spp.). Therefore, the objective of this study was to evaluate the effectiveness of wood vinegar from Eucalyptus urograndis clone GG I144 (EU) as an antiseptic in vitro and in vivo; in addition, to its cytotoxicity and antimicrobial resistance. Fifteen bovines were used, lactating females 3-6 years of age and divided into three groups of five animals each. The wood vinegar was placed in the teats of the animal for 28 days and collections of cellular debris were performed every 7 days. At the Veterinary Microbiology Laboratory (LAMIV) of UFERSA, the samples were processed and serial dilution was performed in Petri plates with plate count agar (PCA) at 37 °C. Cytotoxicity was verified based on morphological alterations and metabolic activity. Morphological changes were not observed in all cells incubated with 1 % pyroligneous extract. The in vitro data demonstrated antimicrobial activity against S. aureus, S. agalactiae, Salmonella, E. coli and P. aeruginosa. The bacteria of the genus Staphylococcus and Corynebacterium were resistant to penicillin (PEN), rifampicin (RIF), nitrofurantoin (NIT), erythromycin (ERI), and ciprofloxacin (CIP). The extract was used in vivo in the post-dipping of dairy cows, which reduced the microbiological load present in the mammary glands from 4.74 to 2.54 CFU, indicating its future use as an antiseptic.

Antifungal Annona muricata L. (soursop) extract targets the cell envelope of multi-drug resistant Candida albicans

ETNOPHARMACOLOGICAL RELEVANCE

Annona muricata L. (soursop) is traditionally used in the treatment of inflammatory diseases, cancer, and infections caused by fungi. The therapeutic activity explored by its medicinal use is generally associated with its phytoconstituents, such as acetogenins and alkaloids. However, its potential antifungal bioactivity as well as its mechanism of action remains to be established.

AIM OF THE STUDY

To evaluate the antifungal activity of the ethanolic extract of A. muricata leaves against multidrug-resistant Candida albicans (ATCC® 10231).

MATERIAL AND METHODS

Phytoconstituents were detected by UFLC-QTOF-MS. The minimum inhibitory concentration was determined, followed by the determination of the minimum fungicidal concentration. For planktonic cells, the growth curve and cell density were evaluated. Studies to understand the mechanism of action on the cell envelope involved crystal violet permeability, membrane extravasation, sorbitol protection, exogenous ergosterol binding assay, metabolic activity, and cell viability. Furthermore, mitochondrial membrane potential was assessed.

RESULTS

Our analyses demonstrated a significant inhibitory effect of A. muricata, with the ability to reduce fungal growth by 58% and cell density by 65%. The extract affected both the fungal plasma membrane and cell wall integrity, with significant reduction of the cell viability. Depolarization of the fungal mitochondrial membrane was observed after treatment with A. muricata. Rutin, xi-anomuricine, kaempferol-3O-rutinoside, nornuciferine, xylopine, atherosperminine, caffeic acid, asimilobine, s-norcorydine, loliolide, annohexocin, annomuricin, annopentocin, and sucrose were identified as extract bioactive components.

CONCLUSIONS

Our findings show that the A. muricata extract is a source of chemical diversity, which acts as a potential antifungal agent with promising application to the therapy of infections caused by C. albicans.