Inhibitory activities of microalgal extracts against Epstein-Barr virus DNA release from lymphoblastoid cells

This study aimed to assess the inhibitory activities of methanol extracts from the microalgae Ankistrodesmus convolutus, Synechococcus elongatus, and Spirulina platensis against Epstein-Barr virus （EBV） in three Burkitt＇s lymphoma （BL） cell lines, namely Akata, B95-8, and P3HR-1. The antiviral activity was assessed by quantifying the cell-free EBV DNA using real-time polymerase chain reaction （PCR） technique. The methanol extracts from Ankistrodesmus convolutus and Synechococcus elongatus displayed low cytotoxicity and potent effect in re- ducing cell-free EBV DNA （EC50〈0.01 μg/ml） with a high therapeutic index （〉28000）. After fractionation by column chromatography, the fraction from Synechococcus elongatus （SEF1） reduced the cell-free EBV DNA most effectively （EC50=2.9 μg/ml, therapeutic index〉69）. Upon further fractionation by high performance liquid chromatography （HPLC）, the sub-fraction SEFI＇a was most active in reducing the cell-free EBV DNA （EC50=1.38 μg/ml, therapeutic index〉14.5）. This study suggests that microalgae could be a potential source of antiviral compounds that can be used against EBV.