title: Leishmanicidal activity of lipophilic extracts of some Hypericum species.
abstract: Leishmaniasis has emerged as the third most prevalent parasite-borne disease worldwide after malaria and filariasis, with about 350 million people at risk of infection. Antileishmanial drugs currently available have various limitations, mainly because of the parasite resistance and side effects. The search of new antileishmanial drugs is ventured throughout the world.
  
  
  OBJECTIVE
  The purpose of this study was to assess the leishmanicidal activity of lipophilic extracts of eight Hypericum species against promastigote forms of Leishmania (Leishmania) amazonensis.
  
  
  METHODS
  The dried and powered materials of aerial parts of H. andinum Gleason, H. brevistylum Choisy, H. caprifoliatum Cham. & Schltdl., H. carinatum Griseb., H. linoides A. St.-Hil., H. myrianthum Cham. & Schltdl., H. polyanthemum Klotzsch ex Reichardt and H. silenoides Juss. were extracted by static maceration with n-hexane. Extracts were evaporated to dryness under reduced pressure and stored at -20°C until biological evaluation and HPLC analysis. The metabolites investigated were dimeric phloroglucinol derivatives, benzophenones and benzopyrans. The yields were expressed as mean of three injections in mg of compound per g of extract (mg/g extract). The effect of Hypericum species on the viability of infective forms of L. (L.) amazonensis was determined using a hemocytometer. Amphotericin B was used as a standard drug. The 50% inhibitory concentration (IC50) values for each extract were determined by linear regression analysis. The cytotoxic effects of extracts were assessed on peritoneal macrophages of BALB/c mice by MTT assay. The concentration that causes 50% of macrophage cytotoxicity (CC50) was determined by linear regression analysis. The selectivity index (SI) of the extracts was determined considering the following equation: CC50 against mammalian cells/IC50 against L. amazonensis.
  
  
  RESULTS
  We demonstrated that H. carinatum, H. linoides and H. polyanthemum were able to kill the parasites in a dose dependent manner. These extracts presented low cytotoxicity against murine macrophages. At 48h of incubation H. polyanthemum presented significant leishmanicidal activity with a 50% inhibitory concentration (IC50) of 36.1µg/ml. The leishmanicidal activity of H. myrianthum was significantly lower than that presented by H. polyanthemum, H. carinatum and H. linoides extracts. H. brevistylum and H. caprifoliatum showed significant leishmanicidal activity only at high concentrations (500 and 1000µg/ml), while H. andinum and H. silenoides were ineffective.
  
  
  CONCLUSIONS
  The promising results demonstrate the importance of the species of the genus Hypericum as source of compounds potentially useful for the treatment of leishmaniasis.
authors: Laboratório de Imunologia, Programa de Pós-Graduação em Ciências da Saúde, Departamento de Ciências Básicas da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Rua Sarmento Leite, 245, sala 206, CEP 90050-170, Porto Alegre, RS, Brazil.
authors: Ana Paula
authors: AP
authors: Dagnino
authors: Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Av. Ipiranga 2752, 90610-000 Porto Alegre, RS, Brazil.
authors: Francisco Maikon Corrêa de
authors: FM
authors: Barros
authors: Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Av. Ipiranga 2752, 90610-000 Porto Alegre, RS, Brazil.
authors: Gari Vidal
authors: GV
authors: Ccana-Ccapatinta
authors: Laboratório de Imunologia, Programa de Pós-Graduação em Ciências da Saúde, Departamento de Ciências Básicas da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Rua Sarmento Leite, 245, sala 206, CEP 90050-170, Porto Alegre, RS, Brazil.
authors: Josiane Somariva
authors: JS
authors: Prophiro
authors: Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Av. Ipiranga 2752, 90610-000 Porto Alegre, RS, Brazil.
authors: Gilsane Lino von
authors: GL
authors: Poser
authors: Laboratório de Imunologia, Programa de Pós-Graduação em Ciências da Saúde, Departamento de Ciências Básicas da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Rua Sarmento Leite, 245, sala 206, CEP 90050-170, Porto Alegre, RS, Brazil. Electronic address: pedror@ufcspa.edu.br.
authors: Pedro R T
authors: PR
authors: Romão
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D020902:Hypericum / Q000737:chemistry*; D007891:Leishmania / Q000187:drug effects*; D017737:Macrophages, Peritoneal / Q000187:drug effects; D008807:Mice, Inbred BALB C; D015394:Molecular Structure; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000378:metabolism*
chemical_list: D000981:Antiprotozoal Agents; D010936:Plant Extracts
keywords: Hypericum species; Leishmania amazonensis; Leishmaniasis; Leishmanicidal activity