Journal of Ethnopharmacology 88 (2003) 241–247 Bioactive alkyl phenols and embelin from Oxalis erythrorhiza Gabriela Egly Feresin a,b , Alejandro Tapia a,c , Maximiliano Sortino d , Susana Zacchino d , Antonieta Rojas de Arias e , Alba Inchausti e , Gloria Yaluff e , Jaime Rodriguez f , Cristina Theoduloz f , Guillermo Schmeda-Hirschmann c,∗ a Instituto de Ciencias Básicas, Universidad Nacional de San Juan, Avda. Ignacio de La Roza 230 Oeste, C.P. 5400 San Juan, Argentina b Instituto de Biotecnolog´ ıa, Universidad Nacional de San Juan, Avda. Libertador General San Mart´ ın 1109 (O), C.P. 5400 San Juan, Argentina c Laboratorio de Qu´ ımica de Productos Naturales, Instituto de Qu´ ımica de Recursos Naturales, Universidad de Talca, Casilla 747, Talca, Chile d Cátedra de Farmacognosia, Facultad de Ciencias Bioqu´ ımicas y Farmacéuticas, Universidad Nacional del Rosario, Suipacha 531, C.P. 2000 Rosario, Argentina e Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, Rio de la Plata y La Gerenza, CP 2511 Asunción, Paraguay f Laboratorio de Cultivo Celular, Facultad de Ciencias de la Salud, Universidad de Talca, Casilla 747, Talca, Chile Received 7 January 2003; received in revised form 2 May 2003; accepted 4 July 2003 Abstract The benzoquinone embelin and four alkyl phenols were isolated from an Argentinean collection of Oxalis erythrorhiza. 3-Heptadecyl-5- methoxy-phenol is reported for the first time. The structures were determined by spectroscopic methods. Embelin presented inhibitory effect on methicillin-resistant Staphylococcus aureus, Escherichia coli and the dermatophytic fungi Epidermophyton floccosum, Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes and Trichophyton rubrum with MICs ranging between 50 and 100 g/ml. Furthermore, embelin was active against Trypanosoma cruzi trypomastigotes with 100% lysis at 100 g/ml and cytotoxicity below the trypanocidal concentration. The new alkyl phenol 3-heptadecyl-5-methoxy-phenol was active towards Leishmania amazonensis and Leishmania donovani promastigotes with 100% lysis at 100 g/ml. The cytotoxicity (IC 50 ) of embelin and the new alkyl phenol on human lung fibroblasts were 739 and 366 M, respectively. The plant is used to treat heart complains, a symptomatology related to Chagas’ disease which is endemic in the San Juan Province, Argentine. © 2003 Elsevier Ireland Ltd. All rights reserved. Keywords: Oxalis erythrorhiza; Oxalidaceae; Embelin; Alkyl phenols; Antimicrobial and antiprotozoal activity 1. Introduction The cushion herb Oxalis erythrorhiza Gillies ex Hooker et Arnott (Oxalidaceae) is known as “boldo de la cordillera” (Cordilleras’ boldo) in the San Juan Province, Argentina. It grows in a belt at 1800–4000m over sea level in the eastern Andean slopes (Lourteig, 1988) and is used as a medicinal plant (Bustos et al., 1996). A decoction of the aerial parts is recommended for hepatic and heart complains. The an- timicrobial activity of the plant has been recently reported (Feresin et al., 2000; Feresin et al., 2001). The hexane (H) and dichloromethane (DCM) extracts of Oxalis erythrorhiza showed activity against dermatophytes and bacteria. In the ∗ Corresponding author. Fax: +56-71-200-448. E-mail addresses: gferesin@unsj.edu.ar (G.E. Feresin), szaabgil@citynet.net.ar (S. Zacchino), sarias@conexion.com.py (A.R.d. Arias), jrodrig@utalca.cl (J. Rodriguez), schmeda@utalca.cl (G. Schmeda-Hirschmann). course of our ongoing project on the detection of bioactive compounds from South American plants, we now report the isolation and antimicrobial activity of alkyl phenols and the benzoquinone embelin, isolated from the active hexane and dichloromethane extracts of Oxalis erythrorhiza. 2. Material and methods 2.1. Plant material Whole plants were collected during the blossoming period in the Bauchazeta district, San Juan Province, Ar- gentina, on December 2000. The plant was identified by Dr. L. Ariza-Espinar, IMBIV-CONICET, Universidad de Cór- doba, Argentina. A voucher specimen has been deposited at the herbarium of the Escuela de Qu´ ımica y Farmacia, Universidad de Chile (SQF), Santiago de Chile under the number SQF 21009. 0378-8741/$ – see front matter © 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/S0378-8741(03)00258-7