Antifungal effect of the liposome encapsulation of the Trans- Caryophylene and its association with fluconazole.

Trans-Caryophyllene (TC), a sesquiterpene, with proven biological activities, which in this work was tested alone, encapsulated in liposomes and associated with Fluconazole in vitro in an attempt to enhance the effect of the drug. Liposomes were characterized from vesicle size, polydispersity index, and Zeta potential, and imaging by scanning electron microscopy. Antifungal assays were performed against Candida albicans, Candida tropicalis and Candida krusei by microdilution to determine the IC50 values and the viability curve. The Minimum Fungicidal Concentration (MFC) was performed by subcultivation in solid medium and the inhibitory effect of the association of TC and Fluconazole and tests to verify morphological changes was performed in micro-cultivation chambers based on concentrations on microdilution plates. The corresponding IC50 data of the substances ranged from 34.4 to 65249 µg/mL, considerably high values compared to the control (Fluconazole). The MFC of all compounds showing fungistatic effect. The performance of the compounds on the cell viability curve was similar in all tested strains, as they showed no antifungal potential when compared to the control (FCZ), when associated with FCZ they showed no significant antifungal activity. The free and liposomal TC also managed to restrict 100% of the fungal dimorphism, in both concentrations, against C. albicans, and against C. tropicalis the isolated TC did not show a significant inhibitory effect; however, against the C. krusei strain inhibited 100% in filamentous growth in both concentrations, which is statistically relevant. The liposomes were homogeneous, with vesicles with diameters of 185.46 nm for the control and 143.8 nm for the liposomal TC, and a surface charge potential of - 42.6 mV. By scanning microscopy, the spherical shapes of the vesicles were verified.

Antifungal activity of farnesol incorporated in liposomes and associated with fluconazole.

Candida infections represent a threat to human health. Candida albicans is the main causative agent of invasive candidiasis, especially in immunosuppressed patients. The emergence of resistant strains has required the development of new therapeutic strategies. In this context, the use of liposomes as drug carrier systems is a promising alternative in drug development. Thus, considering the evidence demonstrating that sesquiterpene farnesol is a bioactive compound with antifungal properties, this study evaluated the activity farnesol-containing liposomes against different Candida strains. The IC50 of farnesol and its liposomal formulation was assessed in vitro using cultures of Candida albicans, Candida tropicalis, and Candida krusei. The Minimum Fungicidal Concentration (MFC) was established by subculture in solid medium. The occurrence of fungal dimorphism was analyzed using optical microscopy. The effects on antifungal resistance to fluconazole were assessed by evaluating the impact of combined therapy on the growth of Candida strains. The characterization of liposomes was carried out considering their vesicular size, polydispersion index, and zeta medium potential, in addition to electron microscopy analysis. Farnesol exerted an antifungal activity that might be associated with the inhibition of fungal dimorphism, especially in Candida albicans. The incorporation of farnesol into liposomes significantly increased its antifungal activity against C. albicans, C. tropicalis, and C. krusei. In addition, liposomal farnesol potentiated the action of fluconazole against C. albicans and C. tropicalis. On the other hand, the association of unconjugated farnesol with fluconazole resulted in antagonistic effects. In conclusion, farnesol-containing liposomes have the potential to be used in antifungal drug development. However, further research is required to investigate how the antifungal properties of farnesol are affected by the interaction with liposomes, contributing to the modulation of antifungal resistance to conventional drugs.

Antifungal Properties of Nerolidol-Containing Liposomes in Association with Fluconazole.

(1) Background: Infections by Candida species represent a serious threat to the health of immunocompromised individuals. Evidence has indicated that nerolidol has significant antifungal properties. Nonetheless, its use is restricted due to a low water solubility and high photosensitivity. The incorporation into liposomes may represent an efficient alternative to improve the physicochemical and biopharmaceutical properties of this compound. The present study aimed to characterize the antifungal properties of liposomal nerolidol, alone or in combination with fluconazole. Of note, this is the first study reporting the antifungal activity of liposomal nerolidol and its potentiating effect in association with fluconazole. (2) Methods: The Inhibitory Concentration 50%-IC50 and minimum fungicide concentrations (MFC) of the substances against Candida albicans (CA), Candida tropicalis (CT), and Candida krusei (CK) were established by subculture in a solid medium. To evaluate the antifungal-enhancing effect, the MFC of fluconazole was determined in the presence or absence of subinhibitory concentrations of nerolidol (free or liposomal). The analysis of fungal dimorphism was performed through optical microscopy and the characterization of liposomes was carried out considering the vesicular size, polydispersion index, and zeta medium potential, in addition to a scanning electron microscopy analysis. (3) Results: The physicochemical characterization revealed that liposomes were obtained as homogenous populations of spherical vesicles. The data obtained in the present study indicate that nerolidol acts as an antifungal agent against Candida albicans and Candida tropicalis, in addition to potentiating (only in the liposomal form) the effect of fluconazole. However, the compound had little inhibitory effect on fungal dimorphism. (4) Conclusions: The incorporation of nerolidol into liposomes improved its antifungal-modulating properties.