Insight into the Antifungal Effects of Propolis and Carnosic Acid—Extension to the Pathogenic Yeast Candida glabrata: New Propolis Fractionation and Potential Synergistic Applications

Abstract

Fungi have traditionally been considered opportunistic pathogens in primary infections caused by virulent bacteria, protozoan, or viruses. Consequently, antimycotic chemotherapy is clearly less developed in comparison to its bacterial counterpart. Currently, the three main families of antifungals (polyenes, echinocandins, and azoles) are not sufficient to control the enormous increase in life-threatening fungal infections recorded in recent decades. Natural substances harvested from plants have traditionally been utilized as a successful alternative. After a wide screening of natural agents, we have recently obtained promising results with distinct formulations of carnosic acid and propolis on the prevalent fungal pathogens Candida albicans and Cryptococcus neoformans. Here, we extended their use to the treatment against the emerging pathogenic yeast Candida glabrata, which displayed lower susceptibility in comparison to the fungi mentioned above. Taking into account the moderate antifungal activity of both natural agents, the antifungal value of these combinations has been improved through the obtention of the hydroethanolic fractions of propolis. In addition, we have demonstrated the potential clinical application of new therapeutical designs based on sequential pre-treatments with carnosic/propolis mixtures, followed by exposure to amphotericin B. This approach increased the toxic effect induced by this polyene.

Natural Substances as Valuable Alternative for Improving Conventional Antifungal Chemotherapy: Lights and Shadows

“…Although individually CA and PP show weak antifungal activity [96,101], we found a significant in vitro antifungal activity with specific combinations of both extracts, recording a synergistic action at appropriate CA/PP ratios. Successful results have been obtained against several prevalent fungal pathogens, like C. albicans [40], C. glabrata [102], C. neoformans [41], and A. fumigatus [80], and our preliminary evidence from A. flavus was also satisfactory. Data from Candida spp.…”

Bio‐guided isolation of aromatic abietane diterpenoids from Salvia canariensis as biopesticides in the control of phytopathogenic fungi

“…Naturally occurring aromatic abietane diterpenoids exhibit a broad range of biological properties. 31 Particularly, carnosic acid and carnosol are known to possess potent antioxidant, 32,33 anti-inflammatory, 34 anticancer 35 and anti-fungal [36][37][38] properties, among others, and the literature is full of works on their therapeutic mechanisms and potential clinical applications. However, only a few works have been reported on their potential on crops protection.…”

Transcriptional Reprogramming of Candida tropicalis in Response to Isoespintanol Treatment

“…Regrettably, the three principal antifungal drug classes (polyenes, echinocandins, and azoles) have been unable to stem the surge in life-threatening fungal infections observed over the past few decades [22]. In response to this pressing clinical challenge, compounds derived from botanical sources have gained traction as a promising alternative [23][24][25].…”