Haematococcus pluvialis is green microalgae well known for its ability of astaxanthin accumulation. In the present investigation, H. pluvialis was culture for 12 days under salinity stress and astaxanthin was extracted from the encysted cells with acetone, methanol, DMSO, and hexane. HPLC analyses showed that astaxanthin was the major content of pigment, the crude extract was tested with the agar well diffusion method for their antibacterial against two Gram-positive bacteria (Staphylococcus

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... eus and Bacillus subtilis), two Gram-negative bacteria (Escherichia coli and P. aeruginosa) as well as for their antifungal activity against (Aspergillus fumigates and Candida albicans. The highest antibacterial activity was observed as 11 mm on S.aureus while as least antibacterial activity was found as 9 mm on P. aeruginosa and no antifungal activity. Astaxanthin crude extract was tested for its effectiveness as antioxidant activity. Also, the extract was screened for their anticancer activities against HepG-2 (hepatocellular carcinoma cells) . The results indicate that the HepG-2 was sensitive at (IC50) with 123.01 ± 2.97 µg/ml.