Abstract
Yeast-like fungi from the Candida genus are predominantly harmless commensals that colonize human skin and mucosal surfaces, but under conditions of impaired host immune system change into dangerous pathogens. The pathogenicity of these fungi is typically accompanied by increased adhesion and formation of complex biofilms, making candidal infections challenging to treat. Although a variety of antifungal drugs have been developed that preferably attack the fungal cell wall and plasma membrane, these pathogens have acquired novel defense mechanisms that make them resistant to standard treatment. This causes an increase in the incidence of candidiasis and enforces the urgent need for an intensified search for new specifics that could be helpful, alone or synergistically with traditional drugs, for controlling Candida pathogenicity. Currently, numerous reports have indicated the effectiveness of plant metabolites as potent antifungal agents. These substances have been shown to inhibit growth and to alter the virulence of different Candida species in both the planktonic and hyphal form and during the biofilm formation. This review focuses on the most recent findings that provide evidence of decreasing candidal pathogenicity by different substances of plant origin, with a special emphasis on the mechanisms of their action. This is a particularly important issue in the light of the currently increasing frequency of emerging Candida strains and species resistant to standard antifungal treatment.
Highlights
Humans have co-evolved with millions of fungal species [1] of which only several hundred can be infectious, most severely affecting individuals with immature or defective immune system—neonates and elderly, individuals with hematological malignancies, acquired immunodeficiency syndrome or congenital immunodeficiencies, and patients after prolonged treatment with broad-spectrum antibiotics
Of more than two hundred species of the Candida genus, about twenty present important medical significance, with most prevalent C. albicans that accounts for nearly half of the diagnosed superficial and systemic candidiases in humans [24,25]
The distribution of particular species among different groups of susceptible patients varies noticeably depending on the geographical region and specific risk factors predisposing to candidal infection that include a variety of conditions based on the weakening of the host immune defense and shifting the balance from the harmless commensal fungus to the dangerous pathogen
Summary
Humans have co-evolved with millions of fungal species [1] of which only several hundred can be infectious, most severely affecting individuals with immature or defective immune system—neonates and elderly, individuals with hematological malignancies, acquired immunodeficiency syndrome or congenital immunodeficiencies, and patients after prolonged treatment with broad-spectrum antibiotics. All Candida species are susceptible to polyenes, the treatment of candidiasis caused by C. krusei and C. glabrata requires a maximal safe dose of drugs; the usage of polyenes is limited by their nephrotoxicity [58] This adverse effect results from the affinity of polyenes to cholesterol located in the membrane of host cells, affecting the permeability of the renal tubules [63,64]. The resistance to polyenes was described for some Candida strains isolated from infected patients, with fungal cells overcoming polyene action by reducing the amount of ergosterol in the plasma membrane This is implemented by some defects in the ERG3 and ERG6 genes encoding enzymes of ergosterol biosynthesis, or its substitution by non-ergosterol cytoplasmic sterols and lipids [65,67]. The harmful side effects of currently used drugs, the increase in resistance to applied treatments, and formation of the protective biofilm structure demonstrate an urgent need for directly targeting and controlling different fungal virulence factors and selecting new types of drugs to limit the resistance as an effective method of combating fungal infection
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
