Results from this study show that PPV is effective against both the
HSV-1 and HSV-2 infections, and flow cytometry offers a quantitative
and highly reproducible anti-HSV drug-susceptibility assay.

Herpes simplex viruses (HSV) are pathogenic. With the emergence of
drug-resistant strains of HSV, new antiviral agents, especially those
with different modes of action, are urgently needed. Prunella vulgaris
L. (Labiatae), a perennial plant commonly found in China and Europe,
has long been used as a folk medicine to cure ailments. In this study,
a polysaccharide fraction was prepared from Prunella vulgaris (PPV),
and its effects on the expressions of HSV-1 and HSV-2 antigens in their
host Vero cells were investigated with flow cytometry. The HSV antigen
increased time-dependently in the infected cells, and PPV reduced its
expression. The effective concentrations of PPV with 50% reductions of
the HSV-1 and HSV-2 antigens were 20.6 and 20.1 microg/ml,
respectively. The novelty of PPV is that it also reduces the antigen
expression of acyclovir-resistant strain of HSV-1. After incubations
with 25-100 microg/ml of PPV the HSV antigen-positive cells were
reduced by 24.8-92.6%, respectively, showing that this polysaccharide
fraction has a different mode of anti-HSV action from acyclovir.

PMID: 15182906 [PubMed - indexed for MEDLINE]