International Journal of Agricultural Policy and Research Vol.2 (11), pp. 373-378, November 2014 Available online at http://www.journalissues.org/IJAPR/ http://dx.doi.org/10.15739/IJAPR.009 © 2014 Journal Issues ISSN 2350-1561 Original Research Article Phytochemical constituents and bioscreening activities of green algae (Ulva Lactuca ) Accepted 30 August, 2014 Dalia F. Abd Elmegeed, Doaa A. Ghareeb*, Muhammed Elsayed and Muhammad El-Saadani Biochemistry department, Faculty of Science, Alexandria University, Alexandria, Egypt. *Corresponding Author Email: d.ghareeb@yahoo.com Tel.: +201277291144 This study was carried out to investigate the phytochemical and biological screening of green algae (Ulva lactuca, UL) crude extract and polysaccharide (PS), U. lactuca was collected from Abu Kir Beach, Alexandria coast, Egypt. Phytochemical screening was assessed by chemical analysis, while the coagulatory effect was assessed by measuring prothrombin time (PT) and activated partial thromboplastin time (APTT). In addition, antioxidant property was measured in form of reduction in TBRSA formation in liver homogenate. Finally, the safety of extract was assessed by RBC toxicity test. Our results showed that, the green algae extract contained alkaloids, flavonoids and saponins that were 79.58, 2.36 and 0.03 mg/100 g algae dry weight, respectively, and the concentration of total phenols was 14.223 mg/100g dry algae tissue. The tested extracts showed antioxidant properties as it inhibited the induction of lipid peroxidation. The U. lactuca crude extract showed anticoagulation property while PS showed coagulation behavior. Finally, UL crude extract has non hemolytic effect on the red blood cells while PS solution has semi hemolytic effect on red blood cells. In conclusion, the UL extracts as natural product have high antioxidant activity due to the presence of total phenolic compounds and the coagulatory effect [assessed by measuring prothrombin time (PT) and activated partial thromboplastin time (APTT)] may be beneficial in the treatment of some cardiovascular diseases. Key words: Ulva lactuca, TBARS, antioxidant, coagulation, anti-inflammatory and RBC toxicity Abbreviations: APTT, Activated partial thromboplastin time; BHT, butylated hydroxytoluen; PS, polysaccharide solution; PT, prothrombin time; TBA, thiobarbituric acid; TBARS, thiobarbituric acid reactive substances; TCA, trichloroacetic acid; UL, Ulva lactuca. INTRODUCTION Nature has provided many things for humankind over the years, including the tools for the first attempts at therapeutic intervention (Nakanishi, 1999). The term natural products is quite commonly understood to refer to herbs, herbal concoctions, dietary supplements, traditional Chinese medicine, or alternative medicine (Holt and Chandra, 2002). However, generally, natural product is a chemical compound or substances produced by a living