Antifungal activity of Gracilaria cervicornis (Turner) J. Agardh against Candida spp.

A B S T R A C T Candida species are considered opportunistic microorganisms present in the normal microbiota of the oral cavity and gastrointestinal and urogenital tracts of human beings. These infections are more common in individuals with compromised immune systems and their frequency has increased over the years. Re-garding bioproducts, recent research from natural sources suggest that algae are a promising group in providing new bioactive substances. The objective of this work is to evaluate the antifungal activity and the in vitro modifying potential of the dichloromethane/methanol extract of G. cervicornis against Can-dida spp. Tests were performed using broth microdilution method to determine the intrinsic activity of the products, and combination therapy with commercial drugs. The intrinsic activity of DMEGC showed fungistatic activity against all Candida species tested at the concentration of 1024 mu g/mL. DMEGC at subin-hibitory concentrations was able to modify the action of Fluconazole against isolated and standard C. kru-sei, reducing the amount of drug needed to inhibit the growth of the microorganism by 50% (IC50) by more than 12-fold. The results show that DMEGC can be used to treat C. krusei in combination therapy with commercial antifungals such as Fluconazole. In addition, its fungistatic activity is important to re-duce the development of drug resistance. Further studies are needed to verify which compounds isolated from the extract were responsible for its antifungal activity and which mechanisms of action.(c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.

Automated summary

This study evaluated the antifungal activity and in vitro modifying potential of the G. cervicornis extract against Candida spp. The extract showed fungistatic activity against all tested Candida species and was able to modify the action of Fluconazole against C. krusei. This research provides new possibilities for combination therapy using G. cervicornis extract to treat Candida infections.