Gellan-Based Hydrogel as a Drug Delivery System for Caffeic Acid Phenethyl Ester in the Treatment of Oral Candida albicans Infections.

Candida albicans can cause various types of oral infections, mainly associated with denture stomatitis. Conventional therapy has been linked to high recurrence, toxicity, and fungal resistance, necessitating the search for new drugs and delivery systems. In this study, caffeic acid phenethyl ester (CAPE) and gellan gum (GG) were studied as an antifungal agent and carrier system, respectively. First, we observed that different GG formulations (0.6 to 1.0% wt/vol) were able to incorporate and release CAPE, reaching a controlled and prolonged release over 180 min at 1.0% of GG. CAPE-GG formulations exhibited antifungal activity at CAPE concentrations ranging from 128 to >512 µg/mL. Furthermore, CAPE-GG formulations significantly decreased the fungal viability of C. albicans biofilms at short times (12 h), mainly at 1.0% of GG (p < 0.001). C. albicans protease activity was also reduced after 12 h of treatment with CAPE-GG formulations (p < 0.001). Importantly, CAPE was not cytotoxic to human keratinocytes, and CAPE-GG formulations at 1.0% decreased the fungal burden (p = 0.0087) and suppressed inflammation in a rat model of denture stomatitis. Altogether, these results indicate that GG is a promising delivery system for CAPE, showing effective activity against C. albicans and potential to be used in the treatment of denture stomatitis.

In vitro effects of selective serotonin reuptake inhibitors on Cryptococcus gattii capsule and biofilm.

Infections caused by Cryptococcus gattii mainly affect immunocompetent individuals and the treatment presents important limitations. This study aimed to validate the efficacy of selective serotonin reuptake inhibitors (SSRI), fluoxetine hydrochloride (FLH), and paroxetine hydrochloride (PAH) in vitro against C. gattii. The antifungal activity of SSRI using the microdilution method revealed a minimal inhibitory concentration (MIC) of 31.25 µg/ml. The combination of FLH or PAH with amphotericin B (AmB) was analyzed using the checkerboard assay and the synergistic effect of SSRI in combination with AmB was able to reduce the SSRI or AmB MIC values 4-8-fold. When examining the effect of SSRI on the induced capsules, we observed that FLH and PAH significantly decreased the size of C. gattii capsules. In addition, the effects of FLH and PAH were evaluated in biofilm biomass and viability. The SSRI were able to reduce biofilm biomass and biofilm viability. In conclusion, our results indicate the use of FLH and PAH exhibited in vitro anticryptococcal activity, representing a possible future alternative for the cryptococcosis treatment.

Metal Nanoparticles to Combat Candida albicans Infections: An Update.

Candidiasis is an opportunistic mycosis with high annual incidence worldwide. In these infections, Candida albicans is the chief pathogen owing to its multiple virulence factors. C. albicans infections are usually treated with azoles, polyenes and echinocandins. However, these antifungals may have limitations regarding toxicity, relapse of infections, high cost, and emergence of antifungal resistance. Thus, the development of nanocarrier systems, such as metal nanoparticles, has been widely investigated. Metal nanoparticles are particulate dispersions or solid particles 10-100 nm in size, with unique physical and chemical properties that make them useful in biomedical applications. In this review, we focus on the activity of silver, gold, and iron nanoparticles against C. albicans. We discuss the use of metal nanoparticles as delivery vehicles for antifungal drugs or natural compounds to increase their biocompatibility and effectiveness. Promisingly, most of these nanoparticles exhibit potential antifungal activity through multi-target mechanisms in C. albicans cells and biofilms, which can minimize the emergence of antifungal resistance. The cytotoxicity of metal nanoparticles is a concern, and adjustments in synthesis approaches or coating techniques have been addressed to overcome these limitations, with great emphasis on green synthesis.

Antimicrobial and Immunomodulatory Activities of Dried Extracts of Echinacea Purpurea

Abstract The use of Echinacea purpurea (EP), a plant native from North America, is widely diffused throughout the world, presenting many pharmacological applications, mainly for the treatment of infections of respiratory and urinary tracts. Due to the widespread commercialization of EP-based products, an effective evaluation of their pharmacological properties is essential to assure efficacy during clinical use. In this study, in vitro tests were performed to evaluate the antimicrobial activity of dried extracts of EP by the microdilution method. In addition, a phagocytosis model was employed to assess the immunomodulatory potential of the extracts. The increase in reactive oxygen species production, as well as the intracellular proliferation rate of Cryptococcus gatti after phagocytosis by macrophages in the presence of EP dried extracts were also evaluated. The analyzed samples showed no significant antibacterial activity; however, a slight antifungal activity was verified. Positive effects of EP extracts on the modulation of cellular immune response were observed in different experiments, indicating that this mechanism may contribute to the control and treatment of infections.