Macroalgal activity against fungal urinary tract infections: in vitro screening and evaluation study

Application of antimicrobial botanical extracts and other natural products is receiving increasing attention. The present study aimed to evaluate the antifungal activities of some macroalgae collected from Alexandria beach, Egypt for treatment of fungal urinary tract infections (UTIs). Methanol extracts of Ulva lactuca showed the highest recorded antifungal activity against Aspergillus flavus and Aspergillus niger, while Enteromorpha linza showed the highest antifungal activity against Candida tropicalis. In addition, methanol extracts of both macroalgae showed a significant urease inhibition of the corresponding fungi. Lineweaver-Burk plots indicated a reversible non-competitive mechanism for U. lactuca extract, whereas E. linza extract showed a reversible competitive inhibition. Fatty acids profile of methanol extracts of U. lactuca and E. linza showed predominance of octadecanoic acid and hexadecanoic acid (48.4% and 62.9% of total fatty acids, respectively). In addition, GC/MS results showed significant proportions of the biologically active compounds; benzodioxoles such as piperonylbutoxide, organochlorines such as p,p'-dichlorodiphenyltrichloroethane (DDT) in U. lactuca and phytosterols such as stigmastan derivatives in E. linza. The present study represents an advancement in the knowledge of the chemistry and antifungal potential of macroalgae against UTIs and offers promising trend for drug discovery from marine macroalgae.