title: Anti-influenza virus principles from Muehlenbeckia hastulata.
abstract: Extracts of Chilean medicinal plants were evaluated in vitro for their activities against influenza virus proliferation in MDCK cells. The most potent extract obtained was from Muehlenbeckia hastulata (Polygonaceae), known as Quilo in Chile, from which three active principles were isolated and identified as pheophorbide a (1), hypericin (2) and protohypericin (3). Minimum inhibitory concentration (MIC) values of 42 ng/ml for compound 1, 2.1 ng/ml for compound 2 and 1.5 ng/ml for the authentic hypericin were determined by using an endpoint assay which comprises pre-incubation of serially diluted specimens with a given amount of the influenza virus, incubation of the pre-incubated virus/specimen with MDCK cells and determination of the hemagglutination (HA) titer of the culture supernatant. Compound 3 was easily converted to 2 on exposure to visible light and, in due course, showed an anti-influenza virus activity (3.1 ng/ml) similar to 2. Although compounds 1-3 were previously isolated from other plants, this is the first report of their isolation from M. hastulata. The high content of 1 (0.06% dry weight of whole plant) is noteworthy. In addition, this is the first report on the isolation of compounds 2 and 3 from a plant other than the genus Hypericum.
authors.affiliation: Department of Kampo Pharmaceutical Sciences, Nihon Pharmaceutical University, 10281 Komuro, Inamachi, Saitama, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Yasuda
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Yamaki
authors.forename: Akiko
authors.initials: A
authors.lastname: Iimura
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Shimotai
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Shimizu
authors.forename: Toshiro
authors.initials: T
authors.lastname: Noshita
authors.forename: Shinji
authors.initials: S
authors.lastname: Funayama
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D002460:Cell Line; D002645:Chickens; D002677:Chile; D004285:Dogs; D006801:Humans; D008826:Microbial Sensitivity Tests; D009975:Orthomyxoviridae / Q000187:drug effects* / Q000254:growth & development; D010936:Plant Extracts / Q000302:isolation & purification* / Q000494:pharmacology*; D010946:Plants, Medicinal; D019664:Polygonaceae
chemical_list: D000998:Antiviral Agents; D010936:Plant Extracts