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

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 10^th to 16^th 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.