Inhibitory effects of kaempferol, quercetin and luteolin on the replication of human parainfluenza virus type 2 in vitro.

The eight flavonoids, apigenin, chrysin, hesperidin, kaempferol, myricetin, quercetin, rutin and luteolin were tested for the inhibition of human parainfluenza virus type 2 (hPIV-2) replication. Three flavonoids out of the eight, kaempferol, quercetin and luteolin inhibited hPIV-2 replication. Kaempferol reduced the virus release (below 1/10,000), partly inhibited genome and mRNA syntheses, but protein synthesis was observed.

Inhibitory effect of traditional herbal (kampo) medicines on the replication of human parainfluenza virus type 2 in vitro.

Thirteen herbal medicines, Kakkonto (TJ-001), Kakkontokasenkyushin'i (TJ-002), Hangekobokuto (TJ-016), Shoseiryuto (TJ-019), Maoto (TJ-027), Bakumondoto (TJ-029), Hochuekkito (TJ-041), Goshakusan (TJ-063), Kososan (TJ-070), Chikujountanto (TJ-091), Gokoto (TJ-095), Saibokuto (TJ-096), and Ryokankyomishingeninto (TJ-119) were tested for human parainfluenza virus type 2 (hPIV-2) replication. Eight (TJ-001, TJ-002, TJ-019, TJ-029, TJ-041, TJ-063, TJ-095 and TJ-119) out of the thirteen medicines had virus growth inhibitory activity. TJ-001 and TJ-002 inhibited virus release, and largely inhibited genome, mRNA and protein syntheses.

Glycyrrhizin inhibits human parainfluenza virus type 2 replication by the inhibition of genome RNA, mRNA and protein syntheses.

The effect of glycyrrhizin on the replication of human parainfluenza virus type 2 (hPIV-2) was examined. Cell fusion induced by hPIV-2 was inhibited by glycyrrhizin, and glycyrrhizin reduced the number of viruses released from the cells. Glycyrrhizin did not change cell morphology at 1 day of culture, but caused some damage at 4 days, as determined by the effect on actin microfilaments.

Ribavirin inhibits human parainfluenza virus type 2 replication in vitro.

The antiviral activities of eight nucleoside analog antiviral drugs (ribavirin, acyclovir, lamivudine, 3'-azido-3'-deoxythymidine, emtricitabine, tenofovir, penciclovir and ganciclovir) against human parainfluenza virus type 2 (hPIV-2) were investigated. Only ribavirin (RBV) inhibited both cell fusion and hemadsorption induced by hPIV-2. RBV considerably reduced the number of viruses released from the cells.

Legume lectins inhibit human parainfluenza virus type 2 infection by interfering with the entry.

Three lectins with different sugar binding specificities were investigated for anti-viral activity against human parainfluenza virus type 2 (hPIV-2). The lectins, concanavalin A (Con A), lens culinaris agglutinin (LCA) and peanut agglutinin (PNA), inhibited cell fusion and hemadsorption induced by hPIV-2. Virus nucleoprotein (NP) gene synthesis was largely inhibited, but fusion (F) and hemagglutinin-neuraminidase (HN) gene syntheses were not.