Leishmanicidal and antichemotactic activities of icetexanes from Salvia uliginosa Benth

Abstract

Background: Several species of Salvia are used as medicinal plants around the world. Biological activities of isolated compounds have been described, being diterpenes frequently responsible for the effects. Purpose: Isolation of diterpenes from Salvia uliginosa Benth. and evaluation of the antichemotactic and leishmanicidal activities of the isolated compounds. Study design: To isolate diterpenes from S. uliginosa and evaluate their antichemotactic and leishmanicidal activities in vitro. Methods: The exudate of S. uliginosa was obtained by rapidly dipping the aerial parts in dichloromethane. The compounds were isolated by repeated column chromatography over silica gel. The effects on L. amazonensis growth, survival, DNA degradation, ROS generation, as well as the antichemotactic activity and cytotoxicity of the compounds towards human erythrocytes and macrophages were evaluated. Results: A novel icetexane diterpene, isoicetexone (IsoICT) along with the known diterpenes icetexone (ICT), and 7-acetoxy-6,7-dihydroicetexone were isolated from the dichloromethane surface exudate of S. uliginosa. The structures were elucidated using NMR and MS experiments, and by comparison with previously reported data. IsoICT and ICT at low concentrations caused completely inhibition of neutrophils migration in vitro. In addition, IsoICT and ICT showed high leishmanicidal activity against L. amazonensis, induced ROS production in parasites and presented low cytotoxicity against macrophages and human erythrocytes, and moderate to high selectivity index. Conclusion: These data indicated that IsoICT and ICT exhibit potent antichemotactic and leishmanicidal effects. Further studies are needed in order to evaluate the in vivo activities as well as the toxicity of the compounds.