en Biotechnology Biotechnology پژوهشي Orginal research papers <p dir="ltr" style="text-align: justify;">The antioxidant activities of<em> Ulva faciata</em>,<em> Nizimuddinia zanardinii </em>and<em> Gracilaria corticata</em> were investigated in Chabahar, Iran. Methanol extract and n-hexane, dichloromethane and ethylacetate fractions used for antioxidative properties test by the total antioxidative activity, 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) &nbsp;free radical scavenging activity, reduction power, metal chelating activity and inhibition of lipid peroxidation methods. The methanolic extracts of three seaweed species showed lower antioxidative properties. The most effective antioxidant properties were observed from the EA fractions of <em>G. corticata </em>and<em> U. faciata</em>. dichloromethane (<em>DCM</em>), fraction of <em>N. zanardinii </em>showed significantly higher total antioxidative activity, DPPH radical scavenging and power reduction in comparison to its n-hexane, EA fractions and crude MeOH extract. There was a strong correlation between the reduction power (r²=0.94) and the total phenolic content of the seaweeds extracts and fractions. The results indicate <em>U. faciata</em> and <em>G. corticata </em>can be potential sources of natural antioxidants and may be efficiently used as nutraceuticals.</p> Antioxidative activity, Phenolic contents, Ulva faciata, Nizimuddinia zanardinii, Gracilaria corticata 802 817 http://jifro.ir/browse.php?a_code=A-10-1272-196&slc_lang=en&sid=1 A. Taheri taherienator@gmail.com 100319475328460016631 100319475328460016631 Yes