Phytomedicine 15 (2008) 520–524 Guatemalan plants extracts as virucides against HIV-1 infection Luis M. Bedoya a , Amparo A ´ lvarez a , Mercedes Bermejo a , Nuria Gonza´lez a , Manuela Beltra´n a , Sonsoles Sa´nchez-Palomino a , Sully M. Cruz b , Isabel Gaita´n b , Esther del Olmo c , Ricardo Escarcena c , Pablo A. Garcı´a c , Armando Ca´ceres b,d , Arturo San Feliciano c , Jose´ Alcamı´ a,Ã a Departamento de Inmunopatologı´a del SIDA, Centro Nacional de Microbiologı´a, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain b Facultad de Ciencias Quı´micas y Farmacia, Universidad de San Carlos, Guatemala c Departamento de Quı´mica Farmace´utica, Facultad de Farmacia, CIETUS, Universidad de Salamanca, 37007 Salamanca, Spain d Laboratorio de Productos Fitofarmace´uticos Farmaya, Guatemala, Spain Abstract Prevention methods to avoid transmission of pathogens, including HIV, are crucial in the control of infectious diseases, not only to block epidemic spread but to avoid long-term treatments leading to emergence of resistances and drug associated side effects. Together with vaccine development, the discovery of new virucidal agents represents a research priority in this setting. In the screening of new compounds with antiviral activity, three Guatemalan plant extracts from Justicia reptans, Neurolaena lobata and Pouteria viridis were evaluated with a classic antiviral assay and were found to inhibit HIV replication. This activity was corroborated by an original recombinant virus assay, leading us to perform a deeper study of the virucidal activity. Active fractions were non-toxic in vitro and also inhibited other enveloped viruses. Moreover, these fractions were able to inhibit the transfer of HIV from dendritic cells (DCs) to lymphocytes, that represents the main way of HIV spread in vivo. r 2007 Elsevier GmbH. All rights reserved. Keywords: HIV; AIDS; Microbicides; Guatemalan plant extracts; Recombinant virus Introduction Human immunodeficiency virus (HIV) is the etiolo- gical agent of Acquired Immunodeficiency Syndrome (AIDS). It spreads through parenteral, vertical or sexual transmission, although currently, more than 90% of all adolescent and adult HIV infections are consequence of heterosexual intercourse (UNAIDS, 2005). Three me- chanisms of viral spread have been described. First, the classical route of entry in which cell-free virions bind to host cells by receptor interactions. Second, an infected cell can infect directly a second cell, without virion release, and third, dendritic cells (DCs) can capture viral particles via binding to C-type lectins presenting the virus to surrounding lymphocytes in a cell environment named viral synapse (Piguet and Sattentau, 2004). This last mechanism increases the efficiency of infection and prevents viral neutralization by antibodies or comple- ment and should be therefore considered as an important target to virucides. Developing countries are currently suffering the worst effects of the AIDS pandemic, and natural products are currently of the most important sources of new ARTICLE IN PRESS www.elsevier.de/phymed 0944-7113/$ - see front matter r 2007 Elsevier GmbH. All rights reserved. doi:10.1016/j.phymed.2007.10.006 Ã Corresponding author. Tel.: +34 918223943; fax: +34 915097919. E-mail address: ppalcami@isciii.es (J. Alcamı´).