Phenolic composition and medicinal usage of Psidium guajava Linn.: Antifungal activity or inhibition of virulence?

Abstract

is a Myrtaceae plant whose medicinal properties are recognized in several locations. The use of teas and tinctures prepared from their leaves has been used to combat infections caused by fungi of the genus . In this study, aqueous extracts of leaves and hydroethanolic were tested to verify the antifungal potential and its chemical composition has been investigated. The microbiological assays were performed by broth microdilution to determine the minimum inhibitory concentration (MIC) and from these the minimum fungicidal concentration was performed (MFC) by subculturing on solid media. A cell viability curve was obtained for demonstration of inhibition of fungal growth of strains of and . Tests to check morphological changes by the action of the extracts were performed in microcultive cameras depleted environment at concentrations of MIC/2, MIC and MIC × 2. Extracts analyzed by high performance liquid chromatography demonstrated flavonoids and phenolic acids. The extracts showed fungistatic effect and no fungicide with MIC>8192 μg/mL, MFC above 8192 μg/mL. The IC was calculated ranging from 1803.02 to 5623.41 μg/mL. It has been found that the extracts affect the morphological transition capability, preventing the formation of pseudohyphae and hyphae. Teas and tinctures, therefore, have the potential antifungal, by direct contact, causing inhibition of fungal multiplication and its virulence factor, the cell dimorphism, preventing tissue invasion. Further studies are needed to elucidate the biochemical pathways and genes assets involved in these processes.

Antibiotic Potential and Chemical Composition of the Essential Oil of Piper caldense C. DC. (Piperaceae)

“…ex DC. And Psidium guajava L., the former having medicinal properties and is used to combat infections caused by fungi of the genus Candida [6,27].…”

“…To obtain the initial concentration of 16,384 µg/mL, the stock solution was diluted in sterile distilled water so that the DMSO concentration in the natural product had no activity in the cells tested. The reference antifungal was fluconazole (Capsule-FLUCOMED), diluted in sterile water at the same oil concentration [27]. For microbiological assays, two Candida albicans strains were used: CA INCQS 40006 (standard strain), obtained from the Oswaldo Cruz Culture Collection of the National Institute for Quality Control in Health (INCQS) and CA URM 4387 (clinical isolate), provided by mycology collection of the Federal University of Recife (URM -University Recife Mycology).…”

Chemical composition, antifungal activity and potential anti-virulence evaluation of the Eugenia uniflora essential oil against Candida spp.

“…Virulence inhibition of Candida species has already been observed both by the action of extracts from other species belonging to the Myrtaceae family as well as by the action of plant products derived from other families. Morais-Braga et al (2016;2017) reported in their study that the aqueous and hydroethanolic extracts from Psidium guajava and Psidium brownianum (Myrtaceae) leaves affected the fungal virulence of C. albicans and C. tropicalis at the 16.384 μg/mL concentration. Brito et al (2015), showed that the C. krusei and C. tropicalis strains cultivated in culture medium in the presence of the Lippia sidoides (Verbenaceae) essential oil did not present pseudohyphae and hyphae at the 256 μg/mL concentration.…”

Peer Review #3 of "Effect of seasonality on chemical profile and antifungal activity of essential oil isolated from leaves Psidium salutare (Kunth) O. Berg (v0.2)"

“…The C. albicans was selected for association study, because, it is the most common pathogenic agent involved in systemic infections and the main strain responsible for infections caused by Candida fungi (Romani, 2012;Yapar, 2014). In previous studies, of our research group, with other species of this genus, P. brownianum and P. guajava extracts had their antifungal potential investigated, obtaining favorable results, where they also managed to affect the phenotypic plasticity of C. albicans and C. tropicalis, reducing the formation process of hyphae and pseudohyphae as their concentrations were increased (Morais- Braga et al, 2016bBraga et al, ,a, 2017. Candida albicans is a polymorphic fungus that can grow both in the yeast form (ovoid form), elongated ellipsoid cells with constrictions in the septa (pseudohyphae), or as true hyphae of parallel walls, as can be observed in Figure 2 -Growth Control (Berman, 2002).…”