Apoptosis mediated leishmanicidal activity of Azadirachta indica bioactive fractions is accompanied by Th1 immunostimulatory potential and therapeutic cure in vivo. Issue 1 (December 2015)

• Record Type: Journal Article
• Authors: Chouhan, Garima; Islamuddin, Mohammad; Want, Muzamil; Abdin, Malik; Ozbak, Hani; Hemeg, Hassan; Sahal, Dinkar; Afrin, Farhat
• Is Part Of: Parasites & vectors. Volume 8:Issue 1(2015)
• Page Start: 1
• Page End: 24
• Publication Date: 2015-12
• Subjects: Visceral Leishmaniasis -- Leishmania donovani -- Apoptosis -- Immunomodulatory -- Antileishmanial -- Immunopotentiating -- Azadirachta indica -- Immunostimulatory -- Leishmanicidal; Parasitism -- Periodicals; Parasites -- Periodicals; Vector-pathogen relationships -- Periodicals; Animals as carriers of disease -- Periodicals; Insects as carriers of disease -- Periodicals; 616.96
• DOI: 10.1186/s13071-015-0788-3
• Languages: English
• ISSNs: 1756-3305

Abstract

Abstract Background Exploration of immunomodulatory antileishmanials of plant origin is now being strongly recommended to overcome the immune suppression evident during visceral leishmaniasis (VL) and high cost and toxicity associated with conventional chemotherapeutics. In accordance, we assessed thein vitro andin vivo antileishmanial and immunomodulatory potential of ethanolic fractions ofAzadirachta indica leaves (ALE) and seeds (ASE). Methods A. indica fractions were prepared by sequential extraction of the powdered plant parts in hexane, ethanol and water. Erythrosin B staining was employed to appraise the anti-promastigote potential of ALE and ASE. Cytostatic or cytocidal mode of action was ascertained and alterations in parasite morphology were depicted under oil immersion light microscopy. Study of apoptotic correlates was performed to deduce the mechanism of induced cell death and anti-amastigote potential was assessed inLeishmania parasitized RAW 264.7 macrophages.In vivo antileishmanial effectiveness was evaluated inL. donovani infected BALB/c mice, accompanied by investigation of immunomodulatory potential of ALE and ASE. Adverse toxicity of the bioactive fractions against RAW macrophages was studied by MTT assay.In vivo side effects on the liver and kidney functions were also determined. Plant secondary metabolites present in ALE and ASE were analysed by Gas chromatography–mass spectrometry (GC-MS). Results ALE and ASE (500 μg ml−1 ) exhibited leishmanicidal activity in a time- and dose-dependent manner (IC50 34 and 77.66 μg ml−1, respectively) with alterations in promastigote morphology and induction of apoptosis. ALE and ASE exerted appreciable anti-amastigote potency (IC50 17.66 and 24.66 μg ml−1, respectively) that was coupled with profoundin vivo therapeutic efficacy (87.76% and 85.54% protection in liver and 85.55% and 83.62% in spleen, respectively). ALE exhibited minimal toxicity with selectivity index of 26.10 whereas ASE was observed to be non-toxic. The bioactive fractions revealed no hepato- and nephro-toxicity. ALE and ASE potentiated Th1-biased cell-mediated immunity along with upregulation of INF-γ, TNF-α and IL-2 and decline in IL-4 and IL-10 levels. GC-MS analysis revealed several compounds that may have contributed to the observed antileishmanial effect. Conclusion Dual antileishmanial and immunostimulatory efficacy exhibited by the bioactive fractions merits their use alone or as adjunct therapy for VL.