Background: some natural and synthetic compounds can prevent, suppress, or reverse the progression of virus infection. Natural products have proven to be the most effective in terms of their ability to act as an antiviral. In the present study, the antiviral potentiality of the bioactive compounds derived from aqueous extract of two Egyptian marine seaweed species (Cystoseiramyrica and Ulva lactuca)were assessed on different viruses. Materials and methods:these two species were collected from Hurghada at the Red Sea and Al-Agami area in Alexandria Mediterranean Sea, Egypt.The assay of cytotoxicity and antiviral activity by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] and by neutralization methods were conducted. Results:these two species have a bioactive compound affected hepatitis A virus (HAV-H 10), Coxsackie B 4 virus,herpes simplex virus types-1 (HSV-1) and type2 (HSV-2), grow and cytopathic effect (CPE) in Vero cells.

Background: aqueous extracts of six species of marine seaweed were studied as antiviral activity on different viruses. Materials and methods: these collected from two sites Hurghada at the Red Sea and Al-Agami area in Alexandria Mediterranean Sea Egypt and belonging to the classes Chlorophyta, Phaeophyta and Rhodophyta were assayed for the cytotoxicity and antiviral activity by MTT [3-(4,5dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] and by neutralization methods.Results: these extracts have antiviral activity to herpes simplex virus types-1 (HSV-1) and type-2 (HSV-2), hepatitis A virus (HAV-H 10 ), and Coxsackie B 4 virus in Vero cells with very low cytotoxicity to the host cells.