Potencial antimicrobiano do óleo essencial de folhas de Lippia Gracilis contra fungos do gênero Candida

Abstract

Fungi of the genus Candida are yeasts that naturally inhabit the human body but can cause infections under specific conditions, such as immunosuppression or prolonged antibiotic use. Candida albicans is associated with infections such as vulvovaginal candidiasis, while C. krusei stands out for causing candidemia and exhibiting intrinsic resistance to antifungals. C. parapsilosis, on the other hand, frequently infects patients using hospital catheters due to its ability to adhere to surfaces.Antifungal resistance, a problem related to the indiscriminate use of medications and inadequate treatments, has encouraged the search for alternative therapies. Among these, essential oils (EOs), particularly those extracted from medicinal plants, have shown promise. The genus Lippia includes approximately 1,035 species, including Lippia gracilis, which is widely used in traditional medicine. Its aromatic leaves produce essential oils rich in thymol and carvacrol, compounds with proven antibacterial and antifungal properties. This study investigated the antifungal potential of L. gracilis essential oil against Candida species, particularly resistant species such as C. krusei and those associated with medical devices, such as C. parapsilosis. The research highlights the potential of phytocompounds as a promising alternative to combat fungal infections and overcome the challenges posed by resistance to conventional antifungals. The study demonstrated that the essential oil was capable of inhibiting fungal growth and biofilms, with up to an 87.7% reduction in biomass at concentrations ranging from 10 to 1.25 mg/mL. Assays indicated that the oil's mechanism of action involved alterations in fungal membrane integrity, including interaction with ergosterol and significant morphological damage, such as cracks in the cell wall and loss of cellular content. However, the observed hemolytic effect, particularly at concentrations such as 1.25 mg/mL, may limit its application to topical use due to the risk of systemic toxicity. Additionally, low concentrations of the essential oil were found to induce oxidative stress in fungal cells. The study concluded that, despite its promising potential, further research on characterization, mechanism of action, and toxic effects in vitro and in vivo is necessary to ensure the safety of its therapeutic use.