Comp. Biochem. Physiol. Vol. 116C, No. 1, pp. 51–54, 1997 ISSN0742-8413/97/$17.00 Copyright  1997 Elsevier Science Inc. PII S0742-8413(96)00127-2 Activity of Compounds Isolated From Chilean Lichens Against Experimental Cutaneous Leishmaniasis Alain Fournet,* Maria-Elena Ferreira,† Antonieta Rojas de Arias,† Susana Torres de Ortiz,† Alba Inchausti,† Gloria Yaluff,† Wanda Quilhot,‡ Ernesto Fernandez‡ and Maria Elena Hidalgo‡ *ORSTOM NSTITUT RANC ¸ AIS DE ECHERCHE CIENTIFIQUE POUR LE E´ VELOPPEMENT EN OOPE ´RATION ASILLA DE ORREO 97, SUNCIO ´ N ARAGUAY NSTITUTO DE NVESTIGACIONES EN IENCIAS DE LA ALUD ASILLA DE ORREO 2511, SUNCIO ´ N ARAGUAY AND SCUELA DE UI´MICA Y ARMACIA ACULTAD DE EDICINA NIVERSIDAD DE ALPARAISO ASILLA 92-V, HILE ABSTRACT. Three secondary metabolites isolated from Chilean lichens, ( +) usnic acid, pannarine and 1′- chloropannarine, were tested against promastigotes forms of three strains of Leishmania ssp. Pannarine and 1′- chloropannarine exhibited in vitro activity at 50 μg/ml and ( +) usnic acid at 25 μg/ml. BALB/c mice infected with Leishmania amazonensis were treated 4 weeks post-infection with ( +) usnic acid by subcutaneous or oral routes for 15 days at 25 mg/kg or by five intralesional injections at interval of 4 days at 25 mg/kg of body weight. The reference drug, N-methylglucamine antimonate (Glucantime), was administered by subcutaneous injections (regimens of 28 mg of pentavalent antimony) for 15 days. The subcutaneous and oral treatments with ( +) usnic did not produce any effect, but by intralesional administration we observed a significant effect that reduced by 43.34% the weight lesions and by 72.28% the parasites loads in infected footpads. C opyright  1997 Elsevier Science Inc. COMP BIOCHEM PHYSIOL 116C;1:51–54, 1997. KEY WORDS. Usnic acid, pannarine, 1′-chloropannarine, Leishmania amazonensis, experimental treatment, BALB/c mice INTRODUCTION ity of the three secondary metabolites and in vivo leishmani- cidal activity of ( +) usnic acid when administered by oral, Cutaneous leishmaniasis and mucocutaneous leishmaniasis subcutaneous and intralesional routes. are endemic diseases in South America, particularlyin Para- guay. Leishmaniasis is initiated by inoculation of Leishmania species into the skin during sand fly bites. Drugs currently MATERIALS AND METHODS available for treatment of leishmaniasisare potentially toxic, Chemicals are inconvenient to administer and frequently give rise to 1′-Chloropannarine was isolated from Erioderma leylandi clinical resistance (2,5). The infection is classically treated (Taylor) Mu ¨ll. Arg., pannarine from Psoroma pallidum Nyl. with pentavalent antimony in the formof sodium stibogluco- and ( +) usnic acid from Protousnea malacea (Stirt) Krog. nate (Pentostam) or N-methylglucamine antimonate (Glu- These lichens were collected in the region of Temuco (IX cantime) and with pentamidine or amphotericin B. Region). Fractionation and purification of these compounds The Instituto de Investigaciones en Ciencias de la Salud were performed as previously described (4). The structures (IICS) and ORSTOM initiated investigations to find new of phenolic compounds are shown in Fig. 1. N-Methylglu- natural active compounds against leishmaniasis. In a pre- camine antimonate (Glucantime) equivalent to 0.28 mg liminary screening, we selected secondary metabolites iso- Sb v /ml was purchased from Rho ˆne-Poulenc (Paris, France). lated from Chilean lichens, namely three phenolic com- pounds, ( +) usnic acid, pannarine and 1′-chloropannarine (10), that displayed in vitro activity against promastigotes Biological Assays forms of three strains of Leishmania ssp., L. braziliensis, L. amazonensis and L. donovani . We describe the in vitro activ- Cultures of Leishmania ssp. were obtained from IICS (Asun- cion) and identified by isoenzyme analysis. Three strains of Leishmania were used during these investigations: L. bra- Correspondence to: A. Fournet, ORSTOM, Casilla de Correo 97, Asuncion, ziliensis (MHOM/BR/75/M2903), L. amazonensis (IFLA/ Paraguay. Tel. and Fax 595-21-609-181; e-mail fournet@ui131.una.py. Received 6 February 1996; accepted 27 June 1996. BR/67/PH8) and L. donovani (MHOM/IN/83/HS-70). The