In Vivo Effects of Papaya Seed Essential Oil on Systemic Candidiasis Model Mice Induced by Fluconazole-Sensitive and -Resistant Isolates of Candida albicans.

Systemic candidiasis caused by Candida albicans has become a serious issue due to high morbidity and mortality. It is very important to develop novel and effective antifungal agents due to the increasing resistance to commonly used drugs such as fluconazole (FLC). In our previous research, the essential oil of Carica papaya L. seed (PSEO) was extracted and in vitro studies demonstrated that PSEO exhibited strong antifungal activity against C. albicans. It is crucial to investigate the therapeutic effect of PSEO in vivo to develop it into a viable antifungal agent. This study aimed to investigate acute toxicity of PSEO and its in vivo effects on a systemic candidiasis model in mice induced with both FLC-sensitive and -resistant C. albicans. The results showed that PSEO showed no acute toxicity up to 100 mg/kg. PSEO and FLC can improve the water intake, food intake, and mental state of systemic candidiasis model mice. The body weight of the infected mice recovered, the survival rate and splenic index increased, the fungal burden decreased, and pathological damage was alleviated to varying degrees. Moreover, the higher the dose of PSEO, the more pronounced the effect. PSEO exhibited significantly better efficacy than FLC against FLC-resistant C. albicans-induced systemic candidiasis. These findings indicate that PSEO holds great promise as a natural, novel, and effective agent for clinical treatment of C. albicans infections, especially for drug-resistant C. albicans infections. This study provides a theoretical basis for the rational development and utilization of papaya seeds.