en Biology & physiology Biology & physiology پژوهشي Orginal research papers <font face="Times New Roman"><span style="font-family: "Times New Roman","serif" font-size: 12pt mso-bidi-language: FA mso-fareast-font-family: "Times New Roman" mso-ansi-language: EN-US mso-fareast-language: EN-US"><em><font size="3"><span style="mso-spacerun: yes"> </span>Dunaliella salina</font></em></span><span style="font-family: "Times New Roman","serif" font-size: 12pt mso-bidi-language: FA mso-fareast-font-family: "Times New Roman" mso-ansi-language: EN-US mso-fareast-language: EN-US">, a green microalga, has been consumed as food and medicine for a long time.The anti-oxidant and anticancer effects are related to more production of β- carotene under stress conditions compared with normal circumstances.The scope of this study was survey of anticancer effect of the ethanol extract of <i>Dunaliella salina</i> algae <font size="3"><span style="mso-bidi-font-style: italic">under stress(EDSS) and normal (EDSN) conditions </span>on death rate of <span style="mso-bidi-font-style: italic">skin carcinoma cell line</span> A431 by MTT [3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide] method in vitro. Our results showed that the β-carotene amount in stress situation was 1.46 times more than in normal condition.The cytotoxic effect of EDSS exposed to 6.25, 12.5, 25, 50, 100 µg/ml in 6, 24, 48 h which was performed by MTT assay showed that there was a significant difference in the various time except in 6 h in both conditions.The results of compared death rate of A431cells exposed to various concentrations of EDSS and EDSN presented significant difference in 6, 24, and 48 h after exposure. <span style="mso-spacerun: yes"> </span>The LC</font>₅₀of EDSS in 24 and 48 h were 15.4 and 0.4 µg/ml , respectively and 478.6 and 46.4 µg/ml for EDSN.</span></font> Dunaliella salina, Anticancer, A431 cell line, MTT assay, β-carotene 283 293 http://jifro.ir/browse.php?a_code=A-10-1-155&slc_lang=en&sid=1 Mo. Emtyazjoo 10031947532846007878 10031947532846007878 No Z. Moghadasi Ziba_mg2000@yahoo.com 10031947532846007879 10031947532846007879 Yes M. Rabbani 10031947532846007880 10031947532846007880 No Ma. Emtyazjoo 10031947532846007881 10031947532846007881 No S. Samadi 10031947532846007882 10031947532846007882 No N. Mossaffa 10031947532846007883 10031947532846007883 No