Anuradha Dube
Publications
-
3.39Impact points
A novel recombinant Leishmania donovani p45, a partial coding region of methionine aminopeptidase, generates protective immunity by inducing a Th1 stimulatory response against experimental visceral leishmaniasis.
International journal for parasitology. 03/2012;
The development of a vaccine against visceral leishmaniasis (VL) conferring long-lasting immunity remains a challenge. Identification and proteomic characterization of parasite proteins led to the detection of p45, a member of the methionine aminopeptidase family. To our knowledge the present study ... [more] The development of a vaccine against visceral leishmaniasis (VL) conferring long-lasting immunity remains a challenge. Identification and proteomic characterization of parasite proteins led to the detection of p45, a member of the methionine aminopeptidase family. To our knowledge the present study is the first known report that describes the molecular and immunological characterization of p45. Recombinant Leishmania donovani p45 (rLdp45) induced cellular responses in cured hamsters and generated Th1-type cytokines from peripheral blood mononuclear cells of cured/endemic VL patients. Immunization with rLdp45 exerted considerable prophylactic efficacy (?85%) supported by an increase in mRNA expression of iNOS, IFN-?, TNF-? and IL-12 and decrease in TGF-? and IL-4, indicating its potential as a vaccine candidate against VL.
-
3.88Impact points
Identification of Novel S-Adenosyl-l-Homocysteine Hydrolase Inhibitors through Homology-Model-Based Virtual Screening, Synthesis, and Biological Evaluation.
Journal of chemical information and modeling. 02/2012; 52(3):777-91.
The present study describes a successful application of computational approaches to identify novel Leishmania donovani (Ld) AdoHcyase inhibitors utilizing the differences for Ld AdoHcyase NAD(+) binding between human and Ld parasite. The development and validation of the three-dimensional (3D) struc... [more] The present study describes a successful application of computational approaches to identify novel Leishmania donovani (Ld) AdoHcyase inhibitors utilizing the differences for Ld AdoHcyase NAD(+) binding between human and Ld parasite. The development and validation of the three-dimensional (3D) structures of Ld AdoHcyase using the L. major AdoHcyase as template has been carried out. At the same time, cloning of the Ld AdoHcyase gene from clinical strains, its overexpression and purification have been performed. Further, the model was used in combined docking and molecular dynamics studies to validate the binding site of NAD in Ld. The hierarchical structure based virtual screening followed by the synthesis of five active hits and enzyme inhibition assay has resulted in the identification of novel Ld AdoHcyase inhibitors. The most potent inhibitor, compound 5, may serve as a "lead" for developing more potent Ld AdoHcy hydrolase inhibitors as potential antileishmanial agents.
-
4.41Impact points
Evaluation of Leishmania donovani Protein Disulfide Isomerase as a Potential Immunogenic Protein/Vaccine Candidate against Visceral Leishmaniasis.
PloS one. 01/2012; 7(4):e35670.
In Leishmania species, Protein disulfide isomerase (PDI) - a redox chaperone, is reported to be involved in its virulence and survival. This protein has also been identified, through proteomics, as a Th1 stimulatory protein in the soluble lysate of a clinical isolate of Leishmania donovani (LdPDI). ... [more] In Leishmania species, Protein disulfide isomerase (PDI) - a redox chaperone, is reported to be involved in its virulence and survival. This protein has also been identified, through proteomics, as a Th1 stimulatory protein in the soluble lysate of a clinical isolate of Leishmania donovani (LdPDI). In the present study, the molecular characterization of LdPDI was carried out and the immunogenicity of recombinant LdPDI (rLdPDI) was assessed by lymphocyte proliferation assay (LTT), nitric oxide (NO) production, estimation of Th1 cytokines (IFN-γ and IL-12) as well as IL-10 in PBMCs of cured/endemic/infected Leishmania patients and cured L. donovani infected hamsters. A significantly higher proliferative response against rLdPDI as well as elevated levels of IFN-γ and IL-12 were observed. The level of IL-10 was found to be highly down regulated in response to rLdPDI. A significant increase in the level of NO production in stimulated hamster macrophages as well as IgG2 antibody and a low level of IgG1 in cured patient's serum was observed. Higher level of IgG2 antibody indicated its Th1 stimulatory potential. The efficacy of pcDNA-LdPDI construct was further evaluated for its prophylactic potential. Vaccination with this construct conferred remarkably good prophylactic efficacy (∼90%) and generated a robust cellular immune response with significant increases in the levels of iNOS transcript as well as TNF-α, IFN-γ and IL-12 cytokines. This was further supported by the high level of IgG2 antibody in vaccinated animals. The in vitro as well as in vivo results thus indicate that LdPDI may be exploited as a potential vaccine candidate against visceral Leishmaniasis (VL).
-
4.41Impact points
Leishmania donovani: immunostimulatory cellular responses of membrane and soluble protein fractions of splenic amastigotes in cured patient and hamsters.
PloS one. 01/2012; 7(1):e30746.
Visceral leishmaniasis (VL), caused by the intracellular parasite Leishmania donovani, L. chagasi and L. infantum is characterized by defective cell-mediated immunity (CMI) and is usually fatal if not treated properly. An estimated 350 million people worldwide are at risk of acquiring infection with... [more] Visceral leishmaniasis (VL), caused by the intracellular parasite Leishmania donovani, L. chagasi and L. infantum is characterized by defective cell-mediated immunity (CMI) and is usually fatal if not treated properly. An estimated 350 million people worldwide are at risk of acquiring infection with Leishmania parasites with approximately 500,000 cases of VL being reported each year. In the absence of an efficient and cost-effective antileishmanial drug, development of an appropriate long-lasting vaccine against VL is the need of the day. In VL, the development of a CMI, capable of mounting Th1-type of immune responses, play an important role as it correlate with recovery from and resistance to disease. Resolution of infection results in lifelong immunity against the disease which indicates towards the feasibility of a vaccine against the disease. Most of the vaccination studies in Leishmaniasis have been focused on promastigote--an infective stage of parasite with less exploration of pathogenic amastigote form, due to the cumbersome process of its purified isolation. In the present study, we have isolated and purified splenic amastigotes of L. donovani, following the traditional protocol with slight modification. These were fractionated into five membranous and soluble subfractions each i.e MAF1-5 and SAF1-5 and were subjected for evaluation of their ability to induce cellular responses. Out of five sub-fractions from each of membrane and soluble, only four viz. MAF2, MAF3, SAF2 and SAF3 were observed to stimulate remarkable lymphoproliferative, IFN-γ, IL-12 responses and Nitric Oxide production, in Leishmania-infected cured/exposed patients and hamsters. Results suggest the presence of Th-1 type immunostimulatory molecules in these sub-fractions which may further be exploited for developing a successful subunit vaccine from the less explored pathogenic stage against VL.
-
4.35Impact points
Treatment of Leishmania donovani-infected hamsters with miltefosine: analysis of cytokine mRNA expression by real-time PCR, lymphoproliferation, nitrite production and antibody responses.
The Journal of antimicrobial chemotherapy. 11/2011; 67(2):440-3.
Miltefosine, an orally effective antileishmanial drug, works directly on the parasite by impairing membrane synthesis and subsequent apoptosis of the parasite and has also been reported to have macrophage-activating functions that aid parasite killing. We investigated the type of immunological respo... [more] Miltefosine, an orally effective antileishmanial drug, works directly on the parasite by impairing membrane synthesis and subsequent apoptosis of the parasite and has also been reported to have macrophage-activating functions that aid parasite killing. We investigated the type of immunological responses generated in miltefosine-treated Leishmania donovani-infected hamsters, which simulate the clinical situation of human kala-azar. Twenty-five-day-old infected hamsters, treated with miltefosine at 40 mg/kg for 5 consecutive days, were euthanized on days 30 and 45 post treatment (p.t.) and checked for parasite clearance and for real-time analysis of mRNAs of the Th1/Th2 cytokines interferon-γ (IFN-γ), interleukin-12 (IL-12), tumour necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), IL-4, IL-10 and transforming growth factor-β (TGF-β), nitric oxide (NO) production, the lymphocyte transformation test (LTT) and antibody responses. Responses were compared with the normal and Leishmania-infected groups at the same time points. By day 45 p.t. there was a significant increase in the mRNA expression of iNOS, IFN-γ, IL-12 and TNF-α, whereas there were significant decreases in IL-4, IL-10 and TGF-β in cured hamsters as compared with their infected counterparts. In vitro stimulation of lymphocytes with concanavalin A and soluble Leishmania donovani antigen showed a maximum LTT response and there was a gradual increase in the NO level (∼7-fold compared with infected counterparts). Anti-Leishmania IgG and IgG1 levels, found to be elevated in the infected group, decreased significantly after treatment but there was a significant increase in IgG2 isotype. Treatment of Leishmania-infected hamsters with miltefosine reverses the Th2-type response into a strong Th1-type immune response.
-
5.65Impact points
Elongation factor-2, a Th1 stimulatory protein of Leishmania donovani, generates strong IFN-γ and IL-12 response in cured Leishmania-infected patients/hamsters and protects hamsters against Leishmania challenge.
Journal of immunology (Baltimore, Md. : 1950). 11/2011; 187(12):6417-27.
In visceral leishmaniasis, Th1 types of immune responses correlate with recovery from and resistance to disease, and resolution of infection results in lifelong immunity against the disease. Leishmanial Ags that elicit proliferative and cytokine responses in PBMCs from cured/exposed/Leishmania patie... [more] In visceral leishmaniasis, Th1 types of immune responses correlate with recovery from and resistance to disease, and resolution of infection results in lifelong immunity against the disease. Leishmanial Ags that elicit proliferative and cytokine responses in PBMCs from cured/exposed/Leishmania patients have been characterized through proteomic approaches, and elongation factor-2 is identified as one of the potent immunostimulatory proteins. In this study, we report the cloning and expression of Leishmania donovani elongation factor-2 protein (LelF-2) and its immunogenicity in PBMCs of cured/exposed Leishmania-infected patients and hamsters (Mesocricetus auratus). Leishmania-infected cured/exposed patients and hamsters exhibited significantly higher proliferative responses to recombinant Lelf-2 (rLelF-2) than those with L. donovani-infected hosts. The soluble L. donovani Ag stimulated PBMCs of cured/exposed and Leishmania patients to produce a mixed Thl/Th2-type cytokine profile, whereas rLelF-2 stimulated the production of IFN-γ, IL-12, and TNF-α but not IL-4 or IL-10. Further, rLelF-2 downregulated LPS-induced IL-10 as well as soluble L. donovani Ag-induced IL-4 production by Leishmania patient PBMCs. The immunogenicity of rLelF-2 was also checked in hamsters in which rLelF-2 generates strong IL-12- and IFN-γ-mediated Th1 immune response. This was further supported by a remarkable increase in IgG2 Ab level. We further demonstrated that rLelF-2 was able to provide considerable protection (∼65%) to hamsters against L. donovani challenge. The efficacy was supported by the increased inducible NO synthase mRNA transcript and Th1-type cytokines IFN-γ, IL-12, and TNF-α and downregulation of IL-4, IL-10, and TGF-β. Hence, it is inferred that rLelF-2 elicits a Th1 type of immune response exclusively and confers considerable protection against experimental visceral leishmaniasis.
-
1.79Impact points
Development and evaluation of tripalmitin emulsomes for the treatment of experimental visceral leishmaniasis.
Journal of liposome research. 07/2011; 22(1):62-71.
The antifungal and antileishmanial agent amphotericin B (AmB) was formulated in tripalmitin based nanosize lipid partices (emulsomes) for macrophage targeting for the treatment of visceral leishmaniasis (VL). Emulsomes were modified by coating them with macrophage-specific ligand (O-palmitoyl mannan... [more] The antifungal and antileishmanial agent amphotericin B (AmB) was formulated in tripalmitin based nanosize lipid partices (emulsomes) for macrophage targeting for the treatment of visceral leishmaniasis (VL). Emulsomes were modified by coating them with macrophage-specific ligand (O-palmitoyl mannan, OPM). The antileishmanial activity of AmB (0.5 and 1 mg/kg) was investigated in-vivo against VL by the inhibition of parasitic load in the spleen of L. donovani infected hamsters after intraperitoneal injections of AmB-Doc (Mycol), plain emulsomes (TPEs) and OPM coated emulsomes (TPEs-OPM). The formulations were found to be less effective at the dose of 0.5 mg/kg. At the dose of 1 mg/kg, formulation TPEs-OPM eliminated intracellular amastigotes of L. donovani within splenic macrophages more efficiently (62.76 ± 3.54 % parasite inhibition) than the formulation TPEs (42.68 ± 2.36 % parasite inhibition) (P < 0.01) or AmB-Doc (25.87 ± 3.87 % parasite inhibition) (P < 0.001). Our results suggest that these formulations (plain and ligand grafted emulsomes) are a promising substitute to the conventional AmB-Doc formulation for the treatment of VL.
-
1.79Impact points
Investigations on feasibility of in situ development of amphotericin B liposomes for industrial applications.
Journal of liposome research. 06/2011; 22(1):8-17.
Amphotericin B (AmB) liposome formulations are very successful in the treatment of fungal infections and leishmaniasis. But higher cost limits its widespread use among people in developing countries. Therefore, we have developed a modified ethanol-injection method for the preparation of AmB liposome... [more] Amphotericin B (AmB) liposome formulations are very successful in the treatment of fungal infections and leishmaniasis. But higher cost limits its widespread use among people in developing countries. Therefore, we have developed a modified ethanol-injection method for the preparation of AmB liposomes. Two liposomal formulations were developed with dimyristoyl phosphatidylcholine [F-1a] and soya phosphatidylcholine [F-2a], along with egg phosphatidyl glycerol and cholesterol. AmB was dissolved in acidified dimethyl acetamide and mixed with ethanolic lipid solution and rapidly injected in 5% dextrose to prepare liposomes. Liposomes were characterized on the basis of size (~100 nm), zeta (-43.3 ± 2.8 mV) and percent entrapment efficiency (>95%). The in vitro release study showed an insignificant difference (P ≥ 0.05) for 24-hour release between marketed AmB liposomes (AmBisome) and F-1a and F-2a. Proliposome concentrate, used for the preparation of in situ liposomes, was physically stable for more than 3 months at experimental conditions. Similarly, AmB showed no sign of degradation in reconstituted liposomes stored at 2-8°C for more than 3 months. IC(50) value of Ambisome (0.18 µg/mL) was comparatively similar to F-1a (0.17 µg/mL) and F-2a (0.16 µg/mL) against intramacrophagic amastigotes. Under experimental conditions, a novel modified method for AmB liposomes is a great success and generates interest for development as a platform technology for many therapeutic drug products.
-
1.59Impact points
Design and development of Amphotericin B bearing polycaprolactone microparticles for macrophage targeting.
Journal of biomedical nanotechnology. 02/2011; 7(1):50-1.
Antileishmanial efficacy of Amphotericin B bearing polycaprolactone (PCL) microparticles was investigated. The microparticles were prepared, optimized and subjected to in vitro characterization for shape (spherically structured), particle size (9.83 +/- 1.12 microm), entrapment efficiency (43.54 +/-... [more] Antileishmanial efficacy of Amphotericin B bearing polycaprolactone (PCL) microparticles was investigated. The microparticles were prepared, optimized and subjected to in vitro characterization for shape (spherically structured), particle size (9.83 +/- 1.12 microm), entrapment efficiency (43.54 +/- 3.98%) and in vitro drug release. The study revealed that PCL microparticles bearing Amphotericin B can be effectively used to target leishmanial parasites residing in macrophages.
-
1.59Impact points
Development and characterization of doxorubicin loaded microparticles against experimental visceral leishmaniasis.
Journal of biomedical nanotechnology. 02/2011; 7(1):135-6.
Visceral leishmaniasis (VL) is the most severe of all the forms of leishmaniasis and usually lethal if untreated. The present work aimed to develop and characterize doxorubicin loaded mannan conjugated microparticles against experimental visceral leishmaniasis for selective and targeted delivery of ... [more] Visceral leishmaniasis (VL) is the most severe of all the forms of leishmaniasis and usually lethal if untreated. The present work aimed to develop and characterize doxorubicin loaded mannan conjugated microparticles against experimental visceral leishmaniasis for selective and targeted delivery of doxorubicin to the macrophages of liver and spleen for the effective chemotherapy of VL. Macrophage targeting using doxorubicin loaded PLGA-microparticles would certainly improve the chemotherapy with reduced side effects against VL.
-
1.59Impact points
Development and performance evaluation of alginate-capped amphotericin B lipid nanoconstructs against visceral leishmaniasis.
Journal of biomedical nanotechnology. 02/2011; 7(1):123-4.
The present study was aimed to assess the improvement of existing treatment regimens of Amphotericin B nanoconstrcuts which synergises with alginate for immunostimulation against visceral leishmaniasis. The particle size of Lip-nano (Plain AmB nanoconstructs) and Alg-Lip-nano (alginate capped Lip-na... [more] The present study was aimed to assess the improvement of existing treatment regimens of Amphotericin B nanoconstrcuts which synergises with alginate for immunostimulation against visceral leishmaniasis. The particle size of Lip-nano (Plain AmB nanoconstructs) and Alg-Lip-nano (alginate capped Lip-nano) was 108.3 +/- 4.3 and 134.2 +/- 5.1 while zeta potential was (+) 28.4 +/- 3.3 and (-) 19.8 +/- 2.1 respectively. Percentage of parasite inhibition (intramacrophagic amastigotes) at 0.1 microg/ml conc. of AmB in case of Alg-Lip-nano (58%) was significantly higher (P = 0.05) compared to Lip-nano (48%). This supports that alginate coating over particles can activate macrophages to synergistically act with AmB in effective killing of parasite. This observation generates interest that immunotherapy with chemotherapeutic activity of AmB can effectively increase cure rate in visceral leishmaniasis.
-
1.89Impact points
Chitosan-based macrophage-mediated drug targeting for the treatment of experimental visceral leishmaniasis.
Journal of microencapsulation. 01/2011; 28(4):301-10.
The potential of chitosan microparticles as a carrier of doxorubicin for the treatment of visceral leishmaniasis was evaluated by macrophage-mediated drug targeting approach. Cationic charge of doxorubicin was masked by complexing it with dextran sulphate (a poly anion) in order to facilitate its in... [more] The potential of chitosan microparticles as a carrier of doxorubicin for the treatment of visceral leishmaniasis was evaluated by macrophage-mediated drug targeting approach. Cationic charge of doxorubicin was masked by complexing it with dextran sulphate (a poly anion) in order to facilitate its incorporation into cationic chitosan microparticles. Prior to in vitro and in vivo studies, characterization studies were carried out systematically: particle size (∼1.049 µm), surface morphology (fluorescence microscopy - spherical structured microparticles), Fourier transform infrared spectroscopy (to characterize effective cross-linking) and differential scanning calorimetry. In vitro studies were carried out in J774.1 in order to check the effective endocytotic uptake of microparticles by macrophages. In vivo studies were conducted in Syrian golden hamsters as per well-established protocols and the results drawn from in vivo studies displayed substantial reduction in leishmanial parasite load for doxorubicin-encapsulated chitosan microparticles: ∼78.2 ± 10.4%, when compared to the control (free doxorubicin): 33.3 ± 2.4%.
-
Piper betle Linn. a maligned Pan-Asiatic plant with an array of pharmacological activities and prospects for drug discoveryCURRENT SCIENCE, VOL. 99, NO. 7, 10 OCTOBER 2010
CURRENT SCIENCE. 10/2010; 99(7-99):922-932.
Piper betle L. is one of the important plants in the Asiatic region which ranks second to coffee and tea in terms of daily consumption. Though the plant is known for abuse, in recent years several reports have been published on the effects of the plant extract and chemical constituents on different ... [more] Piper betle L. is one of the important plants in the Asiatic region which ranks second to coffee and tea in terms of daily consumption. Though the plant is known for abuse, in recent years several reports have been published on the effects of the plant extract and chemical constituents on different biological activities in vitro and in vivo. The leaf extract, fractions and purified compounds are found to play a role in oral hygiene, anti-diabetic, cardiovascular, anti-inflammatory/ immunomodulatory, anti-ulcer, hepato-protective and anti-infective, etc. Patents were also awarded for some of the biological activities like anti-inflammatory, anti-cancer and immunomodulatory associated with leaf extracts and purified compounds. The active compounds isolated from leaf and other parts are hydroxychavicol, hydroxylchavicol acetate, allypyrocatechol, chavibetol, piperbetol, methylpiperbetol, piperol A and piperol B. Phenol-rich leaves of P. betle show high antioxidant activities. A number of biologically active compounds from P. betle have potential for use as medicines, neutraceuticals and industrial compounds. Since the traditional use of P. betle involves chewing, it offers possibilities of use in drug delivery through buccal mucosa bypassing the gastric route.
-
3.25Impact points
Proteome mapping of overexpressed membrane-enriched and cytosolic proteins in sodium antimony gluconate (SAG) resistant clinical isolate of Leishmania donovani.
British journal of clinical pharmacology. 10/2010; 70(4):609-17.
This study aimed to identify differentially overexpressed membrane-enriched as well as cytosolic proteins in SAG sensitive and resistant clinical strains of L. donovani isolated from VL patients which are involved in the drug resistance mechanism. The proteins in the membrane-enriched as well as cyt... [more] This study aimed to identify differentially overexpressed membrane-enriched as well as cytosolic proteins in SAG sensitive and resistant clinical strains of L. donovani isolated from VL patients which are involved in the drug resistance mechanism. The proteins in the membrane-enriched as well as cytosolic fractions of drug-sensitive as well as drug-resistant clinical isolates were separated using two-dimensional gel electrophoresis and overexpressed identified protein spots of interest were excised and analysed using MALDI-TOF/TOF. Six out of 12 overexpressed proteins were identified in the membrane-enriched fraction of the SAG resistant strain of L. donovani whereas 14 out of 18 spots were identified in the cytosolic fraction as compared with the SAG sensitive strain. The major proteins in the membrane-enriched fraction were ABC transporter, HSP-83, GPI protein transamidase, cysteine-leucine rich protein and 60S ribosomal protein L23a whereas in the cytosolic fraction proliferative cell nuclear antigen (PCNA), proteasome alpha 5 subunit, carboxypeptidase, HSP-70, enolase, fructose-1,6-bisphosphate aldolase, tubulin-beta chain have been identified. Most of these proteins have been reported as potential drug targets, except 60S ribosomal protein L23a and PCNA which have not been reported to date for their possible involvement in drug resistance against VL. This study for the first time provided a cumulative proteomic analysis of proteins overexpressed in drug resistant clinical isolates of L. donovani indicating their possible role in antimony resistance of the parasite. Identified proteins provide a vast field to be exploited for novel treatment strategies against VL such as cloning and overexpression of these targets to produce recombinant therapeutic/prophylactic proteins.
-
1.59Impact points
Development and performance evaluation of amphotericin B transfersomes against resistant and sensitive clinical isolates of visceral leishmaniasis.
Journal of biomedical nanotechnology. 06/2010; 6(3):293-302.
The present study was aimed to assess the efficacy of developed transfersome (TF-3) formulation bearing amphotericin B (AmB) against sensitive and resistant clinical isolates of L donovani and compared with conventional liposomal formulation (F-2) and free AmB (F-1). The skin permeation of AmB from ... [more] The present study was aimed to assess the efficacy of developed transfersome (TF-3) formulation bearing amphotericin B (AmB) against sensitive and resistant clinical isolates of L donovani and compared with conventional liposomal formulation (F-2) and free AmB (F-1). The skin permeation of AmB from TF-3 was performed using Franz diffusion cell using rat skin which showed fickian diffusion across the skin. When tested against L. donovani (intramacrophagic amastigotes), it has been observed that TF was more effective than F-1 and F-2 formulation in sensitive and resistant clinical isolates. The data provides evidences that the TF formulation owing to its fluidized behaviour imparted by sodium deoxycholate, enables to penetrate well in the infected cells and thus provide enhanced activity. The permeation study also supports this data as the flux value of AmB through TF formulation was 1.5 fold higher compared to conventional liposomes suggesting improved penetration and better partitioning in skin layers. Implicit to this preliminary data it is evident that the AmB loaded TF formulation has potential as alternate chemotherapeutic approach to control of VL. Potential utilities of novel formulation as a transdermal delivery of AmB for leishmaniasis necessitates further elaborated investigations which is underway in our laboratory.
-
5.20Impact points
16alpha-Hydroxycleroda-3,13 (14)Z-dien-15,16-olide from Polyalthia longifolia: a safe and orally active antileishmanial agent.
British journal of pharmacology. 02/2010; 159(5):1143-50.
New antileishmanials from natural products are urgently needed due to the emergence of drug resistance complicated by severe cytotoxic effects. 16alpha-Hydroxycleroda-3,13 (14)Z-dien-15,16-olide (Compound 1) from Polyalthia longifolia was found to be a potential antileishmanial and non-cytotoxic, as... [more] New antileishmanials from natural products are urgently needed due to the emergence of drug resistance complicated by severe cytotoxic effects. 16alpha-Hydroxycleroda-3,13 (14)Z-dien-15,16-olide (Compound 1) from Polyalthia longifolia was found to be a potential antileishmanial and non-cytotoxic, as evidenced by long-term survival (>6 months) of treated animals. This prompted us to determine its target and, using molecular modelling, identify the interactions responsible for its specific antileishmanial activity. In vitro activity of compound was assessed using intracellular transgenic green fluorescent protein-stably expressed Leishmania donovani parasites. In vivo activity and survival of animals post-treatment were evaluated in L. donovani-infected hamsters. Known property of clerodane diterpenes as potent human DNA topoisomerase inhibitors led us to evaluate the inhibition of recombinant L. donovani topoisomerase I using relaxation assay. Mode of cell death induced by Compound 1 was assessed by phosphotidylserine exposure post-treatment. Molecular modelling studies were conducted with DNA topoisomerase I to identify the binding interactions responsible for its activity. Bioassay-guided fractionation led to isolation of Compound 1 as a non-cytotoxic, orally active antileishmanial. Compound 1 inhibited recombinant DNA topoisomerase I which, ultimately, induced apoptosis. Molecular docking studies indicated that five strong hydrogen-bonding interactions and hydrophobic interactions of Compound 1 with L. donovani DNA-topoisomerase are responsible for its antileishmanial activity. The data reveal Compound 1 is a potent and safe antileishmanial. The study further exploited the structural determinants responsible for its non-cytotoxic and potent activity, to raise the feasibility of specifically targeting the target enzyme responsible for its activity through rational drug design.
-
1.60Impact points
Leishmania donovani: oral therapy with glycosyl 1,4-dihydropyridine analogue showing apoptosis like phenotypes targeting pteridine reductase 1 in intracellular amastigotes.
Experimental parasitology. 02/2010; 125(3):310-4.
Glycosyl 1,4-dihydropyridine analogue (2,6-dimethyl-4-(3-O-benzyl-1,2-O-isopropylidene-beta-l-threo pentofuranos-4-yl)-1-phenyl-1,4-dihydro-pyridine-3,5-dicarboxylic acid diethyl ester) synthesized in our laboratory, inhibited Leishmania donovani infection in vitro and in hamsters (Mesocricetus aura... [more] Glycosyl 1,4-dihydropyridine analogue (2,6-dimethyl-4-(3-O-benzyl-1,2-O-isopropylidene-beta-l-threo pentofuranos-4-yl)-1-phenyl-1,4-dihydro-pyridine-3,5-dicarboxylic acid diethyl ester) synthesized in our laboratory, inhibited Leishmania donovani infection in vitro and in hamsters (Mesocricetus auratus) when administered orally. This analogue is nontoxic, cell-permeable and orally effective. This glycosyl dihydropyridine analogue functioned through arrest of cells in sub-G0/G1-phase, triggering mitochondrial membrane depolarization-mediated programmed cell death of the intracellular amastigotes.
-
Emerging role of vesicular carriers for therapy of visceral leishmaniasis: conventional versus novel.
Critical reviews in therapeutic drug carrier systems. 01/2010; 27(6):461-507.
Visceral leishmaniasis (VL) is a systemic protozoan infection that infects a million people living in subtropical and tropical areas. Drugs are the major treatment available against this fatal infection. Conventional chemotherapy of VL involves treatment with pen- tavalent antimonials, pentamidine, ... [more] Visceral leishmaniasis (VL) is a systemic protozoan infection that infects a million people living in subtropical and tropical areas. Drugs are the major treatment available against this fatal infection. Conventional chemotherapy of VL involves treatment with pen- tavalent antimonials, pentamidine, paromomycin, miltefosine, etc., but this treatment is challenging because of the failure of drugs to penetrate macrophages where the parasite hides, toxic side effects, and drug resistance due to incomplete treatment schedules. The newer therapeutic approach of combination therapy employing multi-drug combinations provides improved treatment of VL because the combination reduces length of treatment, relapse, and risk of toxicity and increases the therapeutic index. Although considerable success has been attained using combination therapies, none has yet achieved commercial status. Therefore, there is an urgent need of designing novel, site-specific leishmanicidal drug carriers for safe and effective management of VL. Colloidal carriers such as liposomes, niosomes, emulsomes, and their engineered versions offer superior therapeutic efficacy over the conventional treatment in terms of site-specific drug delivery related to absolute treatment of disease with reduced side effects and toxicity. The control over spatial and sequential distribution of drug molecules after systemic or localized administration represents the major dispute in drug-delivery systems, and this can be resolved by the use of these colloidal carriers. The present review describes current conventional and combination drug therapies with special consideration given to the emerging role of novel vesicular colloidal carriers designed against VL. Colloidal carriers employing drugs in combination could lead to reductions in the duration of conventional treatment, better patient compliance, and the prevention of anti-leishmanial drug resistance or toxicity.
-
1.19Impact points
Uptake of Biodegradable Gel-Assisted LBL Nanomatrix by Leishmania donovani-Infected Macrophages.
AAPS PharmSciTech. 11/2009;
The aim of this study was to develop novel gel-assisted layer-by-layer (LBL) nanomatrix with high payload of doxorubicin (DOX) and to assess its efficacy against Leishmania donovani. The biodegradable LBL nanomatrix was fabricated using LBL technique using polyions (protamine and sodium alginate) on... [more] The aim of this study was to develop novel gel-assisted layer-by-layer (LBL) nanomatrix with high payload of doxorubicin (DOX) and to assess its efficacy against Leishmania donovani. The biodegradable LBL nanomatrix was fabricated using LBL technique using polyions (protamine and sodium alginate) on decomposable core. The developed system was characterized in vitro in terms of layer-by-layer growth and payload efficiency. The efficacy of optimized formulations was evaluated against L. donovani strain in terms of inhibitory concentration (IC(50)). Uptake studies by infected macrophages were investigated both qualitatively and quantitatively using fluorescence microscopy and flow cytometry. The autogelling property subsequent to core removal inside the nanomatrix resulted in high payload efficiency of DOX (i.e., >70%). The reversal in charge followed the same trend with additional layers, and the magnitude of the charge remained constant up to five complete bilayers of polyions. The DOX can be effectively encapsulated, delivered, and subsequently taken up by L. donovani-infected macrophage cells. The matrix is completely internalized into macrophages showing improved efficacy (IC(50) of formulation is almost </=1.9-fold as compared to plain drug, P < 0.05) against intracellular amastigotes. Having ample of opportunity to manipulate surface architecture, this system demonstrates unique platform as a low cost ideal substitute for visceral leishmaniasis to expensive lipid-based formulations.
-
2.22Impact points
Amplified fragment length polymorphism (AFLP) analysis is useful for distinguishing Leishmania species of visceral and cutaneous forms.
Acta tropica. 10/2009;
The Leishmania strains belonging to cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) have been reported to possess close homology in genome profiles. To confirm this on genetic basis an attempt was made to differentiate Leishmania major; Leishmania tropica and Leishmania donovani genetic... [more] The Leishmania strains belonging to cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) have been reported to possess close homology in genome profiles. To confirm this on genetic basis an attempt was made to differentiate Leishmania major; Leishmania tropica and Leishmania donovani genetically for the first time using amplified fragment length polymorphism (AFLP)-a high throughput DNA fingerprinting technique. The objective of this research work was to identify DNA markers of CL and VL. Ten combinations of selective primers detect a total of 1487 informative AFLP marker. Percentage of polymorphism was 45.12%. Three hundred and thirty-seven unique AFLP markers were also identified in three species of Leishmania. A clear distinction was revealed between L. major and L. donovani. It was inferred by AFLP analysis that a higher rate of polymorphisms occurred among Leishmania species which indicate the distinguished pattern of the disease cause by Leishmania, i.e. VL and CL. Analysis based on polymorphic AFLP markers revealed considerably high genetic variation among the genome of these species which was sufficient to distinguish between CL and VL.
Following (37)
-
Prof NL Sharma
RPG Medical College -
-
Dr. Janmejai K. Srivastava (Dr.J.K.Srivastava)
Amity University -
Sanjay Batra
Central Drug Research Institute -
Neeloo Singh
Central Drug Research Institute
