Suvadra Das

One pot synthesis of gold nanoparticles and application in chemotherapy of wild and resistant type visceral leishmaniasis

Gold nanoparticles (Aunp) through biogenetic processes have induced enormous interest for lower toxicity and precise applications. A rapid, one pot synthesis for uniformly sized gold nanoparticles was developed using polyphenolic compound quercetin. Reduction process was followed at low temperatures in a simple bath type sonicator. Nanoparticle plasmon response was recorded at 540 nm and the average size in TEM was observed at 15.07 nm. Detailed X-ray diffraction (XRD) observations proved fcc crystalline structure of metallic gold and the Fourier transform infrared (FTIR) analysis has confirmed nanoparticles conjugation with quercetin. Leishmaniasis, is a neglected tropical disease (NTD) classified by the World Health Organization (WHO). The leishmanial parasite multiply in host macrophages and most strains have developed drug resistance to available chemotherapeutics. Drug delivery is therefore a major problem in macrophage specific leishmanial parasite infections. New quercetin conjugated gold nanoparticles (QAunp) were successfully evaluated for the first time against leishmanial macrophage infections. Antileishmanial efficiency of QAunp was established against wild type (IC50 15±3), sodium stibogluconate resistant strain (IC50 40±8) and the paramomycin resistant (IC50 30±6) strains. Macrophage uptake of QAunp was complete within an hour as observed in TEM experiments.

Andrographolide nanoparticles in leishmaniasis: characterization and in vitro evaluations.

Andrographolide (AG) is a diterpenoid lactone isolated from the leaves of Andrographis paniculata. AG is a potent and low-toxicity antileishmanial agent. Chemotherapy applications of AG are, however, seriously constrained because of poor bioavailability, short plasma half-life, and inappropriate tissue localization. Nanoparticulation of AG was therefore envisaged as a possible solution. AG nanoparticles (AGnp) loaded in 50:50 poly(DL-lactide-co-glycolic acid) were prepared for delivery into the monocyte–macrophage cells infested with the amastigote form of leishmanial parasite for evaluation in the chemotherapy of leishmaniasis. Particle characteristics of AGnp were optimized by proportionate application of a stabilizer, polyvinyl alcohol (PVA). Physicochemical characterization of AGnp by photon correlation spectroscopy exhibited an average particle size of 173 nm and zeta potential of −34.8 mV. Atomic force microscopy visualization revealed spherical nanoparticles with a smooth surface. Antileishmanial activity was found to be significant for the nanoparticle preparation with 4% PVA (IC50 34 μM) in about one-fourth of the dosage of the pure compound AG (IC50 160 μM). AGnp therefore have significant potential to target the infested macrophage cells and prove valuable in chemotherapy of neglected tropical diseases such as leishmaniasis.

Silymarin nanoparticle prevents paracetamol-induced hepatotoxicity

Silymarin (Sm) is a polyphenolic component extracted from Silybum marianum. It is an antioxidant, traditionally used as an immunostimulant, hepatoprotectant, and dietary supplement. Relatively recently, Sm has proved to be a valuable chemopreventive and a useful antineoplastic agent. Medical success for Sm is, however, constrained by very low aqueous solubility and associated biopharmaceutical limitations. Sm flavonolignans are also susceptible to ion-catalyzed degradation in the gut. Proven antihepatotoxic activity of Sm cannot therefore be fully exploited in acute chemical poisoning conditions like that in paracetamol overdose. Moreover, a synchronous delivery that is required for hepatic regeneration is difficult to achieve by itself. This work is meant to circumvent the inherent limitations of Sm through the use of nanotechnology. Sm nanoparticles (Smnps) were prepared by nanoprecipitation in polyvinyl alcohol stabilized Eudragit RS100® polymer (Rohm Pharma GmbH, Darmstadt, Germany). Process parameter optimization provided 67.39% entrapment efficiency and a Gaussian particle distribution of average size 120.37 nm. Sm release from the nanoparticles was considerably sustained for all formulations. Smnps were strongly protective against hepatic damage when tested in a paracetamol overdose hepatotoxicity model. Nanoparticles recorded no animal death even when administered after an established paracetamol-induced hepatic necrosis. Preventing progress of paracetamol hepatic damage was traced for an efficient glutathione regeneration to a level of 11.3 μmol/g in hepatic tissue due to Smnps.

In vitro susceptibilities of wild and drug resistant leishmania donovani amastigote stages to andrographolide nanoparticle: role of vitamin E derivative TPGS for nanoparticle efficacy.

Visceral leishmaniasis (VL) is a chronic protozoan infection in humans associated with significant global morbidity and mortality. There is an urgent need to develop drugs and strategy that will improve therapeutic response for effective clinical treatment of drug resistant VL. To address this need, andrographolide (AG) nanoparticles were designed with P-gp efflux inhibitor vitamin E TPGS (D-α-tocopheryl polyethyleneglycol 1000 succinate) for sensitivity against drug resistant Leishmania strains. AG loaded PLGA (50∶50) nanoparticles (AGnps) stabilized by vitamin E TPGS were prepared for delivery into macrophage cells infested with sensitive and drug resistant amastigotes of Leishmania parasites. Physico-chemical characterization of AGnps by photon correlation spectroscopy exhibited an average particle size of 179.6 nm, polydispersity index of 0.245 and zeta potential of −37.6 mV. Atomic force microscopy and transmission electron microscopy visualization revealed spherical nanoparticles with smooth surfaces. AGnps displayed sustained AG release up to 288 hours as well as minimal particle aggregation and drug loss even after three months study period. Antileishmanial activity as revealed from selectivity index in wild-type strain was found to be significant for AGnp with TPGS in about one-tenth of the dosage of the free AG and one-third of the dosage of the AGnp without TPGS. Similar observations were also found in case of in vitro generated drug resistant and field isolated resistant strains of Leishmania. Cytotoxicity of AGnp with and without TPGS was significantly less than standard antileishmanial chemotherapeutics like amphotericin B, paromomycin or sodium stibogluconate. Macrophage uptake of AGnps was almost complete within one hour as evident from fluorescent microscopy studies. Thus, based on these observations, it can be concluded that the low-selectivity of AG in in vitro generated drug resistant and field isolated resistant strains was improved in case of AG nanomedicines designed with vitamin E TPGS.

New guar biopolymer silver nanocomposites for wound healing applications.

Wound healing is an innate physiological response that helps restore cellular and anatomic continuity of a tissue. Selective biodegradable and biocompatible polymer materials have provided useful scaffolds for wound healing and assisted cellular messaging. In the present study, guar gum, a polymeric galactomannan, was intrinsically modified to a new cationic biopolymer guar gum alkylamine (GGAA) for wound healing applications. Biologically synthesized silver nanoparticles (Agnp) were further impregnated in GGAA for extended evaluations in punch wound models in rodents. SEM studies showed silver nanoparticles well dispersed in the new guar matrix with a particle size of ~18 nm. In wound healing experiments, faster healing and improved cosmetic appearance were observed in the new nanobiomaterial treated group compared to commercially available silver alginate cream. The total protein, DNA, and hydroxyproline contents of the wound tissues were also significantly higher in the treated group as compared with the silver alginate cream (P < 0.05). Silver nanoparticles exerted positive effects because of their antimicrobial properties. The nanobiomaterial was observed to promote wound closure by inducing proliferation and migration of the keratinocytes at the wound site. The derivatized guar gum matrix additionally provided a hydrated surface necessary for cell proliferation.

Engineered Andrographolide Nanoparticles Mitigate Paracetamol Hepatotoxicity in Mice

ABSTRACTPurposeParacetamol (acetaminophen, APAP) overdose is often fatal due to progressive and irreversible hepatic necrosis. The aim of this work was to design Andrographolide (AG) loaded nanoparticles to prevent similar hepatic necrosis.MethodsFunctionalized AG-loaded PLGA nanoparticles carrying different densities of heparin were prepared following a facile emulsion solvent evaporation technique. Nanoparticle morphology, loading and release kinetics were studied. Hepatic localization of the nanoparticles was investigated in both normal and APAP damaged conditions using FITC fluorescent probe. Different serum parameters and liver histopathology were further examined as indicators of hepatic condition before and after treatment.ResultA collection of heparin functionalized AG-loaded PLGA nanoparticles were designed. Low amount of heparin on the particle surface could rapidly localize the nanoparticles up to the liver. The new functionalized AG nanoparticles affect efficient hepatoprotection in experimental mouse APAP overdose conditions. AG nanoparticle hepatoprotection was due to the rapid regeneration of antioxidant capacity and hepatic GSH store.ConclusionsEngineered nanoparticles loaded with AG provided a fast protection in APAP induced acute liver failure.

Engineered Silybin Nanoparticles Educe Efficient Control in Experimental Diabetes

Silybin, is one imminent therapeutic for drug induced hepatotoxicity, human prostrate adenocarcinoma and other degenerative organ diseases. Recent evidences suggest that silybin influences gluconeogenesis pathways favorably and is beneficial in the treatment of type 1 and type 2 diabetes. The compound however is constrained due to solubility (0.4 mg/mL) and bioavailabilty limitations. Appropriate nanoparticle design for silybin in biocompatible polymers was thus proposed as a probable solution for therapeutic inadequacy. New surface engineered biopolymeric nanoparticles with high silybin encapsulation efficiency of 92.11% and zeta potential of +21 mV were designed. Both the pure compound and the nanoparticles were evaluated in vivo for the first time in experimental diabetic conditions. Animal health recovered substantially and the blood glucose levels came down to near normal values after 28 days treatment schedule with the engineered nanoparticles. Restoration from hyperglycemic damage condition was traced to serum insulin regeneration. Serum insulin recovered from the streptozotocin induced pancreatic damage levels of 0.17±0.01 µg/lit to 0.57±0.11 µg/lit after nanoparticle treatment. Significant reduction in glycated hemoglobin level, and restoration of liver glycogen content were some of the other interesting observations. Engineered silybin nanoparticle assisted recovery in diabetic conditions was reasoned due to improved silybin dissolution, passive transport in nanoscale, and restoration of antioxidant status.

Nanoparticle engineering enhances anticancer efficacy of andrographolide in MCF-7 cells and mice bearing EAC.

Success in cancer chemotherapy relies on efficient delivery of anti-neoplastic drugs, with minimal side-effects on non-cancerous cells. Nanoparticulation of prospective anti-cancer drugs, that were deemed unsuitable due to short biological half life, poor water solubility and low cellular permeability, has been hypothesized to generate superior chemotherapeutic agents, leading to reduced non-specific action and fewer side-effects. In lieu of the above, different synthetic modulations on the putative anti-cancer compound andrographolide (AG) were explored to improve its therapeutic efficiency. Our results indicated that PLGA-nanoparticulation of andrographolide diterpenoid enhanced its anti-cancer properties three fold. Chitosan coating of AG nanoparticles further accentuated cellular localization, induced G1 cell cycle arrest and increased cellular toxicity and apoptosis in MCF-7 cells. The charge modulated nanoparticles were seen to traverse more efficiently through the cytoplasm and accumulate in the nucleus, thus enhancing their anti-proliferative efficacy. In vivo studies confirm that the nanoparticles reduced tumor weight by 68.21% as compared to 24.7% by AG, and increased the life span of mice infected with Ehrlich ascites carcinoma (EAC) by 78.08% as compared to 23.5% for AG alone. This was achieved through development of slow release-type nanoparticle cargo delivery devices, and enhanced the efficiency of AGnps for targeting cancer cells. AG nanoparticles also showed sufficient promise as safe anti-cancer drugs since they had minimal impact on animal hematology. Hence, we successfully prepared non-toxic and delivery-efficient andrographolide nanoparticles, and established for the first time that PLGA-nanoparticulation of andrographolide and additional chitosan coating increased its anti-cancer efficacy in human breast cancer cells and mouse EAC model.

Engineered andrographolide nanosystems for smart recovery in hepatotoxic conditions

Andrographolide (AG) is one of the most potent labdane diterpenoid-type free radical scavengers available from plant sources. The compound is the principal bioactive component in Andrographis paniculata leaf extracts, and is responsible for anti-inflammatory, anticancer, and immunomodulatory activity. The application of AG in therapeutics, however, is severely constrained, due to its low aqueous solubility, short biological half-life, and poor cellular permeability. Engineered nanoparticles in biodegradable polymer systems were therefore conceived as one solution to aid in further drug-like applications of AG. In this study, a cationic modified poly(lactic-co-glycolic) acid nanosystem was applied for evaluation against experimental mouse hepatotoxic conditions. Biopolymeric nanoparticles of hydrodynamic size of 229.7±17.17 nm and ζ-potential +34.4±1.87 mV facilitated marked restoration in liver functions and oxidative stress markers. Superior dissolution for bioactive AG, hepatic residence, and favorable cytokine regulation in the liver tissues are some of the factors responsible for the newer nanosystem-assisted rapid recovery.

Lactoferrin-modified Betulinic Acid-loaded PLGA nanoparticles are strong anti-leishmanials

HighlightsBetulinic acid (BA) is a potential anti‐leishmanial compound.BA delivery by lactoferrin‐PLGA nanoparticle enhances its anti‐leishmanial effects.Lf‐BANPs lower IL‐10 but enhance iNOS expression to exert anti‐leishmanial effects. &NA; Visceral Leishmaniasis (VL), caused by the protozoan parasite Leishmania donovani, is a potentially fatal disease. The only orally bioavailable drug miltefosine is toxic and the effective liposomal Amphotericin B (AmBisome) is limited by its prohibitive cost and requirement for parenteral administration. Therefore, finding a new potential drug candidate and an alternative delivery system is imperative. We report that Betulinic acid (BA), a pentacyclic triterpenoid from Betula alba bark, was loaded onto uniformly spherical PLGA nanoparticles (BANPs; diameter 187.5 ± 5.60 nm) coated with Lactoferrin (Lf‐BANPs). The amastigotes count in macrophages was more effectively reduced by Lf‐BANP than BA and BANP. Lf‐BANPs reduced the pro‐parasitic, anti‐inflammatory cytokine IL‐10, but increased nitric oxide (NO), production in L. donovani‐infected macrophages indicating that Lf‐BANP possesses a significant anti‐leishmanial activity.