Antimicrobial and antioxidant activities of Cystoseira crinita Duby and Ulva intestinalis Linnaeus from the coastal region of Sinop,Turkey

Objective:To evaluate in vitro antimicrobial,antioxidant activities and total phenol contents of Cystoseira crinita and Ulva intestinalis species collected from the coastal region of Sinop.Methods:The antimicrobial activity of each methanolic algae sample was screened by using disc diffusion method against to 15 bacteria and 3 yeasts.The antioxidant potential of the extracts on the stable radical 1,1-diphenyl-2-picrylhydrazyl was determined.The total phenolic content of the 3 methanolic extracts of the seaweed samples were determined by the Folin-Ciocalteu method.Results:The results of antimicrobial assay showed that extracts were more effective against Gram-positive bacteria rather than Gram-negative.In addition,while the algal extracts had antifungal efficacy against Candida krusei,the other yeast strains were not affected at all.According to the findings of antioxidant activity,all methanolic extracts displayed good free radical scavenging activity ranging from IC_(50)=(32.19±0.08)mg/mL to the IC_(50)=(37.57±0.11)mg/mL.The total phenols content of the macroalgal extracts were found as between(5.10±0.16)mg gallic acid equivalent/g and(87.70±1.03)mg gallic acid equivalent/g.In this sense,our findings confirmed that there was a positive linear correlations(r=0.86)between total phenol contents and the IC_(50) values.Conclusions:The data gathered from this study suggested that the seaweeds can be used as a potential natural seafood sources owing to the antimicrobial efficiency and good antioxidant activity.