Candida is a common agent of infection in humans, which has a wide distribution and is a colonizer fungus of the body, occasionally assuming the role of a pathogen. The type of treatment depends on the site of infection and the clinical condition of the patient. Superficial infections, such as mucosal infections, can be treated with topical medications. So-called alternative therapies have rarely been studied, although the literature records the effectiveness of some treatments, especially as complementary therapy. The aims of this review were to analyze evidence of the anti-Candida inhibitory activity of essential oils of the Citrus, Cupressus, Litsea, and Melaleuca species; in addition to addressing the chemical composition, probable mechanisms of antifungal action and studies of toxicity, cytotoxicity, and genotoxicity were included. The literature from Medline/PubMed, Science Direct, Scopus, Web of Science, and the Brazilian database Periodic Capes was reviewed. Thirty-eight articles were selected, which included two articles on Litsea spp., seven on Cupressus spp., thirteen articles on Citrus spp., and twenty-one articles on Melaleuca spp. In conclusion, this study showed in vitro evidence for the use of essential oils of the plant species evaluated for the treatment of infections caused by different Candida species.

Fungal infections by Candida spp. are opportunistic and most often occur in individuals with some predisposing factor. Essential oils (EO) have anti-Candida potential, being a therapeutic alternative to be explored, especially for superficial and mucosal candidiasis. The objective was to analyze the synergistic potential between the EO of Citrus limon, Cupressus sempervirens, Litsea cubeba and Melaleuca alternifolia, and each of them with clotrimazole, to inhibit in vitro the formation and eradication of Candida spp. biofilms. Added to this, the survival of Caenorhabditis elegans was evaluated after exposure to EO, clotrimazole and their synergistic combinations. Anti-Candida activity was determined by microdilution for the substances alone and in EO–EO and EO–clotrimazole combinations. The combinations were performed by the checkerboard method, and the reduction in the metabolic activity of biofilms was determined by the viability of MTT/menadione. C. elegans larvae survival was evaluated after 24 h of exposure to EO, clotrimazole and synergistic combinations. The minimum inhibitory concentration (MIC) of EO ranged from 500 to >4000 µg/mL. The lowest MIC (500 µg/mL) was for C. sempervirens and L. cubeba on a C. krusei isolate; for clotrimazole, the MIC ranged from 0.015 to 0.5 µg/mL. Biofilm inhibition and eradication both ranged from 1000 to >4000 µg/mL. The lethal concentration (LC₅₀) of C. limon, L. cubeba and M. alternifolia was 2000 µg/mL for C. elegans, while for C. sempervirens and clotrimazole, it was not determined within the concentration limits tested. In combination, more than 85% of the larvae survived M. alternifolia–clotrimazole, M. alternifolia–L. cubeba, C. sempervirens–clotrimazole and C. sempervirens–C. limon combinations. This study is the first, to our knowledge, to present a synergistic relationship of EO–EO and EO–clotrimazole combinations on Candida spp. biofilms.

Background: Nanotechnology offers innovative approaches to combat drug-resistant diseases. Silver nanoparticles (AgNPs) have emerged as potent antimicrobial agents in vitro and in vivo. Green synthesis methods, which leverage the bioactive components of the water-soluble fractions of Brazilian kefir (whole water-soluble fraction and smaller than 10 kDa fraction), provide sustainable alternatives to conventional nanoparticles production. However, despite the documented therapeutic benefits of kefir, its potential in nanomedicine remains underexplored. Results: The successful synthesis of silver nanoparticles using water-soluble fractions of kefir was confirmed by UV-Visible spectroscopy and Fourier-transform infrared analyses. The hydrodynamic radius of nanoparticles derived from the entire water-soluble fraction was 1300 nm, while those from the smaller than 10 kDa fraction displayed a radius of 400 nm. All synthesized AgNPs exhibited a zeta potential of -30 mV. The disk diffusion method demonstrated the antimicrobial efficacy of our AgNPs against a range of multidrug-resistant bacteria and Candida fungi (p<0.0001), with no observed toxicity on Drosophila melanogasteron a long-term treatment. Conclusion:This study highlights the potential of these AgNPs as effective antimicrobial agents, particularly against drug-resistant pathogens. Future research is needed to evaluate the minimum inhibitory concentrations of our AgNPs and enhance specificity through conjugation with other compounds. Additionally, further investigations into electron microscopy analysis and various applications, such as disinfectant solutions, wound healing, and antibiotic production, will advance the utilization of kefir-derived AgNPs in healthcare.