title: Asiaticoside induces tumour-necrosis-factor-α-mediated nitric oxide production to cure experimental visceral leishmaniasis caused by antimony-susceptible and -resistant Leishmania donovani strains.
abstract: OBJECTIVE
  The aim of this study was to investigate and characterize the efficacy of asiaticoside in an experimental model of visceral leishmaniasis caused by antimony-susceptible (AG83) and -resistant (GE1F8R and K39) Leishmania donovani.
  
  
  METHODS
  The effect of asiaticoside was evaluated by microscopic counting of intracellular amastigotes in cultured macrophages stained with Giemsa. The antileishmanial effect of the compounds was assessed in infected BALB/c mice by estimation of splenic and liver parasite burdens in Leishman Donovan units. Cytokines were measured by real-time PCR and ELISA. Intracellular tumour necrosis factor-α (TNF-α) was measured by fluorescence-activated cell sorting. Nitric oxide was measured by the Griess reaction.
  
  
  RESULTS
  Besides effectively inhibiting in vitro replication of the parasite within macrophages, asiaticoside treatment resulted in almost complete clearance of the liver and splenic parasite burden when administered at a dose of 5 mg/kg × 10 starting on day +30 of challenge with antimony-susceptible (AG83) and -resistant (GE1F8R and K39) L. donovani. Asiaticoside treatment was associated with a switch in the host from a Th2- to a Th1-type immune response accompanied by the induction of TNF-α-mediated nitric oxide production, all of which are important elements for macrophage function in antileishmanial defence mechanisms.
  
  
  CONCLUSIONS
  These results suggest that oral therapy with asiaticoside shows promising antileishmanial efficacy in animals infected by antimony-susceptible (AG83) and -resistant (GE1F8R and K39) L. donovani.
authors.affiliation: Division of Infectious Disease and Immunology,  Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032,  India.
authors.forename: Siddhartha Kumar
authors.initials: SK
authors.lastname: Bhaumik
authors.forename: Joydeep
authors.initials: J
authors.lastname: Paul
authors.forename: Kshudiram
authors.initials: K
authors.lastname: Naskar
authors.forename: Subir
authors.initials: S
authors.lastname: Karmakar
authors.forename: Tripti
authors.initials: T
authors.lastname: De
mesh_terms: D000818:Animals; D000965:Antimony / Q000494:pharmacology; D000981:Antiprotozoal Agents / Q000008:administration & dosage* / Q000494:pharmacology; D004195:Disease Models, Animal; D004351:Drug Resistance; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007893:Leishmania donovani / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000188:drug therapy*; D008099:Liver / Q000469:parasitology; D008264:Macrophages / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D008853:Microscopy; D009569:Nitric Oxide / Q000276:immunology / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D013154:Spleen / Q000469:parasitology; D016896:Treatment Outcome; D014315:Triterpenes / Q000008:administration & dosage*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism*
chemical_list: D000981:Antiprotozoal Agents; D014315:Triterpenes; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D000965:Antimony; C004446:asiaticoside