title: Ellagitannins from Tuberaria lignosa as entry inhibitors of HIV.
abstract: Screening of plants from the Iberian Peninsula for anti-human immunodeficiency virus (-HIV) activity revealed that aqueous extract of Tuberaria lignosa gave positive results. Following an activity-guided procedure, the crude extract was counterextracted, and the subsequent fractions obtained tested for their anti-HIV activity in vitro. The bioassay-guided fractionation of the extract afforded an ellagitannin enriched fraction (EEF) isolated for the first time from this species. This EEF exhibited antiviral activity against HIV in MT-2 infected cells, with an IC(50) value of 2.33mug/ml (selectivity index greater than 21). Inhibition of HIV infection by EEF appears to be mediated by CD4 down-regulation, the main receptor for HIV entry. CXCR4 and CCR5 receptors were not affected by EEF, explaining why EEF is able to inhibit R5 and X4 infections.
authors.affiliation: Centro Nacional de Microbiología, Instituto de Salud Carlos III, Crt. Majadahonda a Pozuelo, 28220 Majadahonda, Madrid, Spain.
authors.forename: L M
authors.initials: LM
authors.lastname: Bedoya
authors.forename: M J
authors.initials: MJ
authors.lastname: Abad
authors.forename: S
authors.initials: S
authors.lastname: Sánchez-Palomino
authors.forename: J
authors.initials: J
authors.lastname: Alcami
authors.forename: P
authors.initials: P
authors.lastname: Bermejo
mesh_terms: D019380:Anti-HIV Agents / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D030601:Cistaceae / Q000737:chemistry*; D015536:Down-Regulation; D006678:HIV / Q000187:drug effects*; D015658:HIV Infections / Q000517:prevention & control*; D006801:Humans; D047348:Hydrolyzable Tannins / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D020128:Inhibitory Concentration 50; D019169:Jurkat Cells; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D019713:Receptors, CCR5; D019718:Receptors, CXCR4; D016662:Virus Integration / Q000187:drug effects*
chemical_list: D019380:Anti-HIV Agents; D047348:Hydrolyzable Tannins; D010936:Plant Extracts; D019713:Receptors, CCR5; D019718:Receptors, CXCR4