title: Aqueous extracts from peppermint, sage and lemon balm leaves display potent anti-HIV-1 activity by increasing the virion density.
abstract: BACKGROUND
  Aqueous extracts from leaves of well known species of the Lamiaceae family were examined for their potency to inhibit infection by human immunodeficiency virus type 1 (HIV-1).
  
  
  RESULTS
  Extracts from lemon balm (Melissa officinalis L.), peppermint (Mentha x piperita L.), and sage (Salvia officinalis L.) exhibited a high and concentration-dependent activity against the infection of HIV-1 in T-cell lines, primary macrophages, and in ex vivo tonsil histocultures with 50% inhibitory concentrations as low as 0.004%. The aqueous Lamiaceae extracts did not or only at very high concentrations interfere with cell viability. Mechanistically, extract exposure of free virions potently and rapidly inhibited infection, while exposure of surface-bound virions or target cells alone had virtually no antiviral effect. In line with this observation, a virion-fusion assay demonstrated that HIV-1 entry was drastically impaired following treatment of particles with Lamiaceae extracts, and the magnitude of this effect at the early stage of infection correlated with the inhibitory potency on HIV-1 replication. Extracts were active against virions carrying diverse envelopes (X4 and R5 HIV-1, vesicular stomatitis virus, ecotropic murine leukemia virus), but not against a non-enveloped adenovirus. Following exposure to Lamiaceae extracts, the stability of virions as well as virion-associated levels of envelope glycoprotein and processed Gag protein were unaffected, while, surprisingly, sucrose-density equilibrium gradient analyses disclosed a marked increase of virion density.
  
  
  CONCLUSIONS
  Aqueous extracts from Lamiaceae can drastically and rapidly reduce the infectivity of HIV-1 virions at non-cytotoxic concentrations. An extract-induced enhancement of the virion's density prior to its surface engagement appears to be the most likely mode of action. By harbouring also a strong activity against herpes simplex virus type 2, these extracts may provide a basis for the development of novel virucidal topical microbicides.
authors: Department of Virology, University of Heidelberg, Heidelberg, Germany. Silvia.Geuenich@med.uni-heidelberg.de
authors: Silvia
authors: S
authors: Geuenich
authors: Christine
authors: C
authors: Goffinet
authors: Stephanie
authors: S
authors: Venzke
authors: Silke
authors: S
authors: Nolkemper
authors: Ingo
authors: I
authors: Baumann
authors: Peter
authors: P
authors: Plinkert
authors: Jürgen
authors: J
authors: Reichling
authors: Oliver T
authors: OT
authors: Keppler
mesh_terms: D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D015658:HIV Infections / Q000821:virology*; D015497:HIV-1 / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D019686:Lamiaceae; D008264:Macrophages; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D014771:Virion / Q000737:chemistry / Q000187:drug effects*; D014779:Virus Replication / Q000187:drug effects; D014867:Water
chemical_list: D010936:Plant Extracts; D014867:Water