title: Induction of a refractory state to viral infection in mammalian cells by a plant inhibitor isolated from leaves of Melia azedarach L.
abstract: A partially purified plant inhibitor (Meliacin) isolated from Melia azedarach L induced in cells a refractory state to virus infection. Meliacin was active in a large variety of continuous and/or primary cell cultures. A state of maximum virus resistance was achieved after 2 h of incubation and was maintained for at least 15 h; later on it declined but it was fully regained after a second pulse of Meliacin. Interferon was not detected in the supernatant of cells treated with Meliacin and a measurable increase in ds-RNA dependent protein kinase activity was not observed in extracts of Meliacin-treated cells. The antiviral state was not transferred by either extracellular fluid or direct cell-to-cell contact. An active cell metabolism was required for Meliacin action, which was partially reversed in the presence of actinomycin D. It appears that Meliacin is not an interferon-like substance, which induces an antiviral state based on a still unexplained mechanism.
authors: Laboratorio de Virología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
authors: G M
authors: GM
authors: Andrei
authors: E B
authors: EB
authors: Damonte
authors: R A
authors: RA
authors: de Torres
authors: C E
authors: CE
authors: Coto
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002478:Cells, Cultured; D006801:Humans; D007372:Interferons / Q000096:biosynthesis; D007700:Kinetics; D010455:Peptides; D010940:Plant Proteins; D010944:Plants / Q000032:analysis; D014721:Vesicular stomatitis Indiana virus / Q000187:drug effects / Q000502:physiology; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D010455:Peptides; D010940:Plant Proteins; C058031:meliacin; D007372:Interferons