Antifungal Activity of Mexican Propolis on Clinical Isolates of Candida Species

Abstract

Infections caused by micro-organisms of the genus <i>Candida</i> are becoming a growing health problem worldwide. These fungi are opportunistic commensals that can produce infections-clinically known as candidiasis-in immunocompromised individuals. The indiscriminate use of different anti-fungal treatments has triggered the resistance of <i>Candida</i> species to currently used therapies. In this sense, propolis has been shown to have potent antimicrobial properties and thus can be used as an approach for the inhibition of <i>Candida</i> species. Therefore, this work aims to evaluate the anti-<i>Candida</i> effects of a propolis extract obtained from the north of Mexico on clinical isolates of <i>Candida</i> species. <i>Candida</i> species were specifically identified from oral lesions, and both the qualitative and quantitative anti-<i>Candida</i> effects of the Mexican propolis were evaluated, as well as its inhibitory effect on <i>C. albicans</i> isolate's germ tube growth and chemical composition. Three <i>Candida</i> species were identified, and our results indicated that the inhibition halos of the propolis ranged from 7.6 to 21.43 mm, while that of the MFC and FC₅₀ ranged from 0.312 to 1.25 and 0.014 to 0.244 mg/mL, respectively. Moreover, the propolis was found to inhibit germ tube formation (IC₅₀ ranging from 0.030 to 1.291 mg/mL). Chemical composition analysis indicated the presence of flavonoids, including pinocembrin, baicalein, pinobanksin chalcone, rhamnetin, and biochanin A, in the Mexican propolis extract. In summary, our work shows that Mexican propolis presents significant anti-<i>Candida</i> effects related to its chemical composition, and also inhibits germ tube growth. Other <i>Candida</i> species virulence factors should be investigated in future research in order to determine the mechanisms associated with antifungal effects against them.