Protein from Phaleria macrocarpa Fruit Aqueous Extract Inhibits Early and Late Replication Phases of Human Herpes Virus Type-1

Abstract

Background: Phaleria macrocarpa fruit is known to have protein but the antiviral activity potential has not been explored. Objective: To determine the antiviral activity of Phaleria macrocarpa fruit protein aqueous extract (PMFPAE) and the fractions against human herpesvirus type 1 (HHV-1). Methods: Protein from P. macrocarpa fruit aqueous extract was precipitated using ammonium sulphate and followed by fractionation on Sephadex G-25. Cytotoxicity was determined in Vero cells and followed by determination of antiviral activity by plaque reduction assay against a clinical strain of HHV-1. Effect of PMFPAE on virus replication was determined in pre-treatment, time-addition and time-removal assays. Results: PMFPAE and its fractions were non-cytotoxic to Vero cells with 50% cytotoxic concentration (CC50) values ranged between 96 ± 1.3 to 1450 ± 2 μg/mL. PMFPAE have good anti-HHV-1 activity with Selective Index (SI) of 80.6 but reduces in fractions P1 to P6 ranging between 4.2 and 67.9. Fractions with high SI were P1 and P2 contained high molecular weight (MW) proteins and P6 has the lowest MW suggestively peptides. Treatment with PMFPAE to host cells prior to virus infection had little effect on inhibiting HHV-1 replication. Treatment with PMFPAE affects virus early and late replication phase with plaque inhibition percentage increased during 10th to 16th hour post-infection. Conclusion: PMFPAE contained non-cytotoxic proteins that affects HHV-1 early and late replication phases. Proteins with high antiviral activity resides in fractions with high MW and very low MW peptides. Key words: Phaleria macrocarpa fruit protein, Fractionation, Cytotoxicity, Anti-Human herpes virus type-1.