A Novel Substance Purified from <i>Perilla Frutescens</i> Britton Inhibits an Early Stage of HIV-1 Replication without Blocking Viral Adsorption

Abstract

Pf-gp6, a 6 kDa anti-degranulation glycoprotein purified from the extract of Perilla frutescens, was examined for its antiviral activity against HIV-1 and HIV-2 in vitro. HIV-1-induced cytopathic effect and proviral DNA synthesis were inhibited in the presence of Pf-gp6. The 50% inhibitory concentrations of Pf-gp6 for various HIV-1 strains, including clinical isolates and CCR5-using (R5) HIV-1, ranged between 1.3 and 71.0 microg/ml, depending on the combination of viral strain and host cell. Furthermore, Pf-gp6 did not directly inactivate infectious viral particles. A time-of-addition experiment revealed that Pf-gp6 lost its activity before zidovudine but after the CXCR-4 antagonist AMD3100 during the early stage of viral infection. Although the pinpoint target of Pf-gp6 remains to be elucidated, it may interfere with a step between viral entry and reverse transcription.