Phytosterol compounds having antiviral efficacy.
The present study is focused on the antiviral action patterns obtained in vitro with synthetic sterolester comprising compositions on virus-bearing host cell-lines. Appropriate cell-lines were infected with HIV-1, human Cytomegalovirus (HCMV) and Herpes simplex virus (HSV). There appears to exist a clear anti-infective efficacy for a selected number of such ester compounds, provided they are formulated into spontaneously dispersible concentrates, which in aqueous dilution engender ultramicro-emulsions having micelles in the lowest nanosize region. A significant protection against HIV-induced cytopathogenic effect was demonstrated employing a methyltetrazolium salt reduction assay on HIV-infected MT4 cells when they were incubated with such concentrates. A similar effect was evidenced with the same concentrates, when preincubating concentrated virus, but not the target cells. Antiviral activity appeared to be remarkable also on HCMV infections in vitro, where a blocking effect on immediate-early antigen expression in fibroblast monolayers could be observed. Similarly, HSV-associated glycoprotein antigen in VERO cells also suggests that virus-cell interaction and/or virus multiplication could have been blocked at a very early point of time. This would be quite different from antiviral action-patterns studied so far and imputed into the current models of explanation. Proper solubilization of the employed phytosterol compounds is essential for achieving the described activity modes. The often recommended liposome formulations would not be well suited for such compounds and such purpose, since after dilution they produce aqueous macro-emulsions, only. Furthermore, liposome formulations tend to coalesce and exhibit Marangoni effects.