In vitro antifungal activity and phytochemical characterization of Eugenia uniflora, Libidibia ferrea and Psidium guajava

The aim of this study was evaluate the in vitro antifungal activity of crude extracts from Eugenia uniflora, Libidibia ferrea and Psidium guajava. The extracts were obtained by turbo-extraction using water (AQ) or acetone-water (AC-W) (7:3, v/v) as solvents and lyophilized to obtain the crude extracts (CE). The CE were characterized by UV-Vis, TLC and HPLC. The activity of CEs was investigated against clinical isolates of Candida spp. and the Minimum Inhibitory Concentration (MIC), MIC50 and MIC90 were determinated. The analysis by TLC showed that all CEs presented polyphenols (flavonoids and tannins). The CEs from E. uniflora showed higher amount of polyphenols (30.35 ± 2.15%, AC-W) and the HPLC analysis revealed the tannins in all extracts. The CEs of E. uniflora showed MIC range from 1.9 to 500.0 µg/mL, and lower values of MIC50 and MIC90 against non-albicans Candida isolates. Regarding L. ferrea and P. guajava, the results showing MIC from 3.9 to 1000.0 µg/mL (CE-AQ) against C. albicans. The results demonstrate antifungal performance from CE against various species of Candida spp., suggesting that the herbal species may be use as new potential antifungal agents. Additionally, the polyphenol content can play a pivotal role in the antifungal properties of CE.

Effect of the crude extract of Eugenia uniflora in morphogenesis and secretion of hydrolytic enzymes in Candida albicans from the oral cavity of kidney transplant recipients.

BACKGROUND: Candida albicans is a diploid yeast that in some circumstances may cause oral or oropharyngeal infections. Yeasts virulence factors contribute for both the maintenance of colonizing strains in addition to damage and cause tissue invasion, thus the establishment of infection occurs. The limited arsenal of antifungal drugs for the treatment of candidiasis turn the investigation of natural products mandatory for the discovery of new targets for antifungal drug development. Therefore, tropical countries emerge as important providers of natural products with potential antimicrobial activity. This study aimed to investigate morphogenesis and secretion of hydrolytic enzymes (phospholipase and proteinase) in the presence of the CE of Eugenia uniflora. METHODS: The isolates were tested for their ability to form hyphae in both solid and liquid media under three different conditions: YPD + 20% FBS, Spider medium and GlcNac and the ability to secrete phospholipase and proteinase in the presence of 2000 µg/mL of E. uniflora. RESULTS: The CE of E. uniflora inhibited hypha formation in both liquid and solid media tested. It also impaired hydrolytic enzymes production. CONCLUSIONS: This was the first study to describe the interaction of a natural product with the full expression of three different factors in C. albicans. E. uniflora may be an alternative therapeutic for oral candidiasis in the future.