Mannose-conjugated curcumin-chitosan nanoparticles: Efficacy and toxicity assessments against Leishmania donovani

In vitro and In vivo Effects of Ethanolic Extract of Fumaria parviflora Lam. Embedded in Chitosan Nanoparticles Against Leishmania major

INTRODUCTION

Fumaria has been traditionally used to treat skin damages due to anti-inflammatory properties. In the present study, we evaluated the effect of the ethanolic extract of Fumaria parviflora Lam. (F. parviflora) against Leishmania major (L. major) using chitosan biopolymer drug delivery system both In vitro and In vivo models.

MATERIALS AND METHODS

The ethanolic extract of F. parviflora was analyzed by HPLC to determine its active ingredients content. The extract was then loaded on chitosan nanoparticles (CNPs). The parasite was treated with various concentrations of the ethanolic extract, CNPs and CNPs loaded with F. parviflora extract (CNPs@ F. parviflora). The size of lesions of treated mice were measured on a weekly basis. The parasite burden was evaluated 8 weeks after treatment.

RESULTS

The HPLC analysis showed the presence of Fumaric acid at a high concentration. The percentage of the drug released from CNPs@ F. parviflora within 24 and 72 h were 65% and 90% respectively. The results showed that F. parviflora extract and CNPs@ F. parviflora caused 84% and 96% growth inhibition of L. major promastigotes as revealed by Neubauer chamber counting and MTT test respectively. The IC50 values of F. parviflora extract and CNPs@ F. parviflora were 450 and 68.4 µg/ml respectively. In amastigote assay, the best results showed in CNPs@ F. parviflora that only 2% of macrophages were infected with amastigotes. In vivo experiments for mice treated with F. parviflora and CNPs @ F. parviflora in comparison to control group showed a significant reduction (P < 0.05) in the mean diameter of the lesions (2.3 and 1.72 mm and 9.91 mm respectively).

CONCLUSION

The ethanolic extract of F. parviflora both as standalone and loaded in CNPs showed promising inhibitory effects against L. major both upon In vitro and In vivo experimentation as well as therapeutic effects for wound healing in infected mice.

Effect of Protein Corona on the Specificity and Efficacy of Nanobioconjugates to Treat Intracellular Infections

Encapsulating drugs into functionalized nanoparticles (NPs) is an alternative to reach the specific therapeutic target with lower doses. However, when the NPs are in contact with physiological media, proteins adsorb on their surfaces, forming a protein corona (PC) biomolecular layer, acquiring a distinct biological identity that alters their interactions with cells. Itraconazole (ITZ), an antifungal agent, is encapsulated into PEGylated and/or functionalized NPs with high specificity for macrophages. It is evaluated how the PC impacts their cell uptake and antifungal effect. The minimum inhibitory concentration and colony-forming unit assays demonstrate that encapsulated ITZ into poly(ethylene glycol) (PEG) NPs improves the antifungal effect compared with NPs lacking PEGylation. The improvement can be related to the synergistic effect of the encapsulated ITZ and NPs composition and the reduction of PC formation in PEG NPs. Functionalized NPs with anti-F4/80 and anti-MARCO antibodies, or mannose without PEG and treated with PC, show an improved uptake but, in the presence of PEG, significantly reduce the endocytosis, dominating the stealth effect from PEG. Therefore, the PC plays a crucial role in the nanosystem uptake and antifungal effects, which suggests the need for in vivo model studies to evaluate the effect of PC in the specificity and biodistribution.

Curcumin-loaded nanostructured systems for treatment of leishmaniasis: a review

Leishmaniasis is a neglected tropical disease that has affected more than 350 million people worldwide and can manifest itself in three different forms: cutaneous, mucocutaneous, or visceral. Furthermore, the current treatment options have drawbacks which compromise efficacy and patient compliance. To face this global health concern, new alternatives for the treatment of leishmaniasis have been explored. Curcumin, a polyphenol obtained from the rhizome of turmeric, exhibits leishmanicidal activity against different species of Leishmania spp. Although its mechanism of action has not yet been fully elucidated, its leishmanicidal potential may be associated with its antioxidant and anti-inflammatory properties. However, it has limitations that compromise its clinical use. Conversely, nanotechnology has been used as a tool for solving biopharmaceutical challenges associated with drugs, such as curcumin. From a drug delivery standpoint, nanocarriers (1-1000 nm) can improve stability, increase solubility, promote intracellular delivery, and increase biological activity. Thus, this review offers a deep look into curcumin-loaded nanocarriers intended for the treatment of leishmaniasis.

Effectiveness In Vivo and In Vitro of Polymeric Nanoparticles as a Drug Release System in the Treatment of Leishmaniasis

Leishmaniasis is a neglected disease caused by the parasite of the genus Leishmania. Current treatment regimens are obsolete and cause several side effects, promoting poor patient compliance, in addition to the vast majority already having the potential for resistance. Therefore, polymeric nanoparticles emerge as one of the viable alternatives to overcome existing limitations, through passive or active vectorization. This review aims to summarize the latest studies of polymeric nanoparticles as an alternative treatment for leishmaniasis. In the first section, the main pharmacokinetic and pharmacodynamic challenges of current drugs are reported. The second section details how nanoparticles with and without functionalization are efficient in the treatment of leishmaniasis, discussing the characteristics of the polymer in the formulation. In this way, polymeric nanoparticles can improve the physicochemical properties of leishmanicidal drugs, improving solubility and stability, as well as improve the release of these drugs, directly or indirectly reaching monocytes/macrophages. 64.28% drugs were focused on the treatment of visceral leishmaniasis, and 28.57% on cutaneous leishmaniasis. The most chosen polymers in the literature are chitosan (35.71%) and PLGA (35.71%), the others represented 14.30% drugs, with all able to manage the drug release and increase the in vitro and/or in vivo efficacy of the original molecule. However, there are several barriers for these nanoformulations to cross laboratory research and is necessary more in-depth studies about the metabolites and degradation pathways of the polymers used in the formulations and plasma proteomics studies.

The bioavailability, metabolism and microbial modulation of curcumin-loaded nanodelivery systems

Curcumin (Cur), the major bioactive component of turmeric (Curcuma longa) possesses many health benefits. However, low solubility, stability and bioavailability restricts its applications in food. Recently, nanocarriers such as complex coacervates, nanocapsules, liposomes, nanoparticles, nanomicelles, have been used as novel strategies to solve these problems. In this review, we have focused on the delivery systems responsive to the environmental stimuli such as pH-responsive, enzyme-responsive, targeted-to-specific cells or tissues, mucus-penetrating and mucoadhesive carriers. Besides, the metabolites and their biodistribution of Cur and Cur delivery systems are discussed. Most importantly, the interaction between Cur and their carriers with gut microbiota and their effects of modulating the gut health synergistically were discussed comprehensively. In the end, the biocompatibility of Cur delivery systems and the feasibility of their application in food industry is discussed. This review provided a comprehensive review of Cur nanodelivery systems, the health impacts of Cur nanocarriers and an insight into the application of Cur nanocarriers in food industry.

Mannose facilitates Trichinella spiralis expulsion from the gut and alleviates inflammation of intestines and muscles in mice

Trichinellosis is a major zoonotic parasitosis which is a vital risk to meat food safety. It is requisite to exploit new strategy to interdict food animal Trichinella infection and to obliterate Trichinella from food animals to ensure meat safety. Mannose is an oligosaccharide that specifically binds to the carbohydrate-recognition domain of C-type lectin; it has many physiological functions including reliving inflammation and regulating immune reaction. The purpose of this study was to investigate the suppressive role of mannose on T. spiralis larval invasion and infection, its effect on intestinal and muscle inflammation, and immune responses after challenge. The results showed that compared to the saline-treated infected mice, the mannose-treated infected mice had less intestinal adult and muscle worm burdens, mild inflammation of intestine and muscle of infected mice. The levels of specific anti-Trichinella IgG (IgG1/IgG2a), IgA and sIgA in mannose-treated infected mice were obviously inferior to saline-treated infected mice (P < 0.01). Furthermore, the levels of two cytokines (IFN-γ and IL-4) in mannose-treated infected mice were also significantly lower than the saline-treated infected mice (P < 0.01). The protective effect of the mannose against Trichinella infection might be not related to specific antibody and cellular immune responses. The above results demonstrated that mannose could be considered as a novel adjuvant therapeutic agent for anti-Trichinella drugs to block larval invasion at early stage of Trichinella infection.

A Review on Recent Advances in Mannose-Functionalized Targeted Nanocarrier Delivery Systems in Cancer and Infective Therapeutics

Unmodified nanocarriers used in the chemotherapy of cancers and various infectious diseases exhibit prolonged blood circulation time, prevent enzymatic degradation and increase chemical stability of encapsulated therapeutics. However, off-target effect and lack of specificity associated with unmodified nanoparticles (NPs) limit their applications in the health care system. Mannose (Man) receptors with significant overexpression on antigen-presenting cells and macrophages are among the most admired targets for cancer and anti-infective therapeutics. Therefore, development of Man functionalized nanocarriers targeting Man receptors, for target specific drug delivery in the chemotherapy have been extensively studied. Present review expounds diverse Man-conjugated NPs with their potential for targeted drug delivery, improved biodistribution profiles and localization. Additionally, the review gives detailed account of the interactions of mannosylated NPs with various biological systems and their characterization not discussed in earlier published reports is discussed.

Modular nanotheranostic agents for protistan parasitic diseases: Magic bullets with tracers

Protistan parasitic infections contribute significantly to morbidity and mortality, causing more than 2 billion human infections annually. However, current treatments are often limited; due to ineffective drugs and drug resistance, thus better options are urgently required. In the present context, theranostics agents are those that offer simultaneous detection, diagnosis and even treatment of protistan parasitic diseases. "Nanotheranostics" is the term used to describe such agents, that are around 100 nm or less in size. Anti-parasitic activity of nanoparticles (NPs) has been reported, and many have useful intrinsic imaging properties, but it is perhaps their multifunctional nature that offers the greatest potential. NPs may be used as adapters onto which various subunits with different functions may be attached. These subunits may facilitate targeting parasites, coupled with toxins to eradicate parasites, and probe subunits for detection of particles and/or parasites. The modular nature of nano-platforms promises a "mix and match" approach for the construction of tailored agents by using combinations of these subunits against different protistan parasites. Even though many of the subunits have shown promise alone, these have not yet been put together convincingly enough to form working theranostics against protistan parasites. Although the clinical application of nanotheranostics to protistan parasitic infections in humans requires more research, we conclude that they offer not just a realisation of Paul Ehrlich's long imagined "magic bullet" concept, but potentially are magic bullets combined with tracer bullets.

Emerging strategies and challenges of molecular therapeutics in antileishmanial drug development

Molecular therapy refers to targeted therapies based on molecules which have been intelligently directed towards specific biomolecular structures and include small molecule drugs, monoclonal antibodies, proteins and peptides, DNA or RNA-based strategies, targeted chemotherapy and nanomedicines. Molecular therapy is emerging as the most effective strategy to combat the present challenges of life-threatening visceral leishmaniasis, where the successful human vaccine is currently unavailable. Moreover, current chemotherapy-based strategies are associated with the issues of ineffective targeting, unavoidable toxicities, invasive therapies, prolonged treatment, high treatment costs and the development of drug-resistant strains. Thus, the rational approach to antileishmanial drug development primarily demands critical exploration and exploitation of biochemical differences between host and parasite biology, immunocharacteristics of parasite homing, and host-parasite interactions at the molecular/cellular level. Following this, the novel technology-based designing and development of host and/or parasite-targeted therapeutics having leishmanicidal and immunomodulatory activity is utmost essential to improve treatment efficacy. Thus, the present review is focused on immunological and molecular checkpoint targets in host-pathogen interaction, and molecular therapeutic prospects for Leishmania intervention, and the challenges ahead.

Mannosylated Systems for Targeted Delivery of Antibacterial Drugs to Activated Macrophages

Macrophages are a promising target for drug delivery to influence macrophage-associated processes in the body, namely due to the presence of resistant microorganisms in macrophages. In this work, a series of mannosylated carriers based on mannan, polyethylenimine (PEI) and cyclodextrin (CD) was synthesized. The molecular architecture was studied using FTIR and ¹H NMR spectroscopy. The particle size, from small 10-50 nm to large 500 nm, depending on the type of carrier, is potentially applicable for the creation of various medicinal forms: intravenous, oral and inhalation. Non-specific capture by cells with a simultaneous increase in selectivity to CD206+ macrophages was achieved. ConA was used as a model mannose receptor, binding galactosylated (CD206 non-specific) carriers with constants of the order of 10⁴ M^-1 and mannosylated conjugates of 10⁶-10⁷ M^-1. The results of such primary "ConA-screening" of ligands are in a good agreement in terms of the comparative effectiveness of the interaction of ligands with the CD206+ macrophages: non-specific (up to 10%) absorption of highly charged and small particles; weakly specific uptake of galactosylated polymers (up to 50%); and high affine capture (more than 70-80%) of the ligands with grafted trimannoside was demonstrated using the cytometry method. Double and multi-complexes of antibacterials (moxifloxacin with its adjuvants from the class of terpenoids) were proposed as enhanced forms against resistant pathogens. In vivo pharmacokinetic experiments have shown that polymeric carriers significantly improve the efficiency of the antibiotic: the half-life of moxifloxacin is increased by 2-3 times in conjugate-loaded forms, bio-distribution to the lungs in the first hours after administration of the drug is noticeably greater, and, after 4 h of observation, free moxifloxacin was practically removed from the lungs of rats. Although, in polymer systems, its content is significant-1.2 µg/g. Moreover, the importance of the covalent crosslinking carrier with mannose label was demonstrated. Thus, this paper describes experimental, scientifically based methods of targeted drug delivery to macrophages to create enhanced medicinal forms.

Multifunctional nanoparticles based on marine polysaccharides for apremilast delivery to inflammatory macrophages: Preparation, targeting ability, and uptake mechanism

Hydrophobic drug encapsulation inside targeted nanoparticles can enhance accumulation in inflamed sites, limit toxicity to healthy tissue, and improve pharmacokinetics compared to free drug dosing. This study reports a functionalized marine polysaccharide nanoparticle with a controlled release, targeting abilities, and in-situ imaging properties. Carbon dots functionalized Enteromorpha polysaccharide/Mannose/Methionine functionalized Chitosan (CDs.EP/Man/Meth.Cs) NPs could deliver apremilast to inflammatory macrophages and Caco-2 intestinal cells as an in vitro model for application in oral drug delivery to cure IBD. The nanoparticles were simply a polyelectrolyte complex between cationic functionalized chitosan and anionic polysaccharide of Enteromorpha prolifera. Functionalized polysaccharides and the prepared NPs were well characterized. The functionalized nanoparticles could overcome the limitation of poor drug bioavailability and showed a high loading capacity of (45 %) with a controlled release of about (74.5 %). Confocal laser scanning imaging showed higher cellular uptake of the modified nanoparticles than that of the unmodified nanoparticles in LPS-activated RAW 264.7 macrophages and Caco-2 cells. The effect of functionalization on the cellular uptake targetability was assessed using spectrofluorometric measurements after mannose competition. Anti-inflammatory activity of apremilast-loaded NPs is more elevated than the free drug. These results suggest the feasibility of using functionalized EP/Cs nanoparticles in IBD oral drug delivery.

Mannosylated Polymeric Ligands for Targeted Delivery of Antibacterials and Their Adjuvants to Macrophages for the Enhancement of the Drug Efficiency

Bacterial infections and especially resistant strains of pathogens localized in macrophages and granulomas are intractable diseases that pose a threat to millions of people. In this paper, the theoretical and experimental foundations for solving this problem are proposed due to two key aspects. The first is the use of a three-component polymer system for delivering fluoroquinolones to macrophages due to high-affinity interaction with mannose receptors (CD206). Cytometry assay determined that 95.5% macrophage-like cells were FITC-positive after adding high-affine to CD206 trimannoside conjugate HPCD-PEI1.8-triMan, and 61.7% were FITC-positive after adding medium-affine ligand with linear mannose label HPCD-PEI1.8-Man. The second aspect is the use of adjuvants, which are synergists for antibiotics. Using FTIR and NMR spectroscopy, it was shown that molecular containers, namely mannosylated polyethyleneimines (PEIs) and cyclodextrins (CDs), load moxifloxacin (MF) with dissociation constants of the order of 10⁻⁴–10⁻⁶ M; moreover, due to prolonged release and adsorption on the cell membrane, they enhance the effect of MF. Using CLSM, it was shown that eugenol (EG) increases the penetration of doxorubicin (Dox) into cells by an order of magnitude due to the creation of defects in the bacterial wall and the inhibition of efflux proteins. Fluorescence spectroscopy showed that 0.5% EG penetrates into bacteria and inhibits efflux proteins, which makes it possible to increase the maximum concentration of the antibiotic by 60% and maintain it for several hours until the pathogens are completely neutralized. Regulation of efflux is a possible way to overcome multiple drug resistance of both pathogens and cancer cells.

Nanomedicine-based strategies to improve treatment of cutaneous leishmaniasis

Nanomedicine strategies were first adapted and successfully translated to clinical application for diseases, such as cancer and diabetes. These strategies would no doubt benefit unmet diseases needs as in the case of leishmaniasis. The latter causes skin sores in the cutaneous form and affects internal organs in the visceral form. Treatment of cutaneous leishmaniasis (CL) aims at accelerating wound healing, reducing scarring and cosmetic morbidity, preventing parasite transmission and relapse. Unfortunately, available treatments show only suboptimal effectiveness and none of them were designed specifically for this disease condition. Tissue regeneration using nano-based devices coupled with drug delivery are currently being used in clinic to address diabetic wounds. Thus, in this review, we analyse the current treatment options and attempt to critically analyse the use of nanomedicine-based strategies to address CL wounds in view of achieving scarless wound healing, targeting secondary bacterial infection and lowering drug toxicity.

Drug-delivery nanoparticles for bone-tissue and dental applications

The use of nanoparticles as biomaterials with applications in the biomedical field is growing every day. These nanomaterials can be used as contrast imaging agents, combination therapy agents, and targeted delivery systems in medicine and dentistry. Usually, nanoparticles are found as synthetic or natural organic materials, such as hydroxyapatite, polymers, and lipids. Besides that, they are could also be inorganic, for instance, metallic or metal-oxide-based particles. These inorganic nanoparticles could additionally present magnetic properties, such as superparamagnetic iron oxide nanoparticles. The use of nanoparticles as drug delivery agents has many advantages, for they help diminish toxicity effects in the body since the drug dose reduces significantly, increases drugs biocompatibility, and helps target drugs to specific organs. As targeted-delivery agents, one of the applications uses nanoparticles as drug delivery particles for bone-tissue to treat cancer, osteoporosis, bone diseases, and dental treatments such as periodontitis. Their application as drug delivery agents requires a good comprehension of the nanoparticle properties and composition, alongside their synthesis and drug attachment characteristics. Properties such as size, shape, core-shell designs, and magnetic characteristics can influence their behavior inside the human body and modify magnetic properties in the case of magnetic nanoparticles. Based on that, many different studies have modified the synthesis methods for these nanoparticles and developed composite systems for therapeutics delivery, adapting, and improving magnetic properties, shell-core designs, and particle size and nanosystems characteristics. This review presents the most recent studies that have been presented with different nanoparticle types and structures for bone and dental drug delivery.

Is Curcumin at the Threshold of Therapeutic Effectiveness on Patients with Colon Cancer?-A Systematic Review

Curcumin, obtained from curcuma longa, has been the subject of decades of scientific investigation on its therapeutic usefulness. It is reported to possess several therapeutic properties, of which anti-colon cancer is of interest in this review. Clinically however, curcumin has yet to firm up its place among established anti-colon cancer therapeutic contenders. We aimed to systematically review prevailing clinical evidence on the role of curcumin in colon cancer treatment. The review drawing from literature on clinical studies indicates fairly long term tolerability. No regression of tumor was reported when curcumin was the sole intervention. Increase in p53 level expression was reported in a placebo controlled study but no reduction in PGE2 or 5HETE. Pharmacokinetic data on healthy humans indicate that formulated curcumin delivery systems present significantly higher systemic bioavailability. It appears therefore that the clinical use of curcumin can potentially be realized only through appropriate formulation interventions. Systematic Review Registration: [website], identifier [registration number].

A Systematic Review of Curcumin and its Derivatives as Valuable Sources of Antileishmanial Agents

BACKGROUND

In recent years, antimonial agents and other synthetic antileishmanial drugs, such as amphotericin B, paromomycin, and many other drugs, have restrictions in use due to the toxicity risk, high cost, and emerging resistance to these drugs. The present study aimed to review the antileishmanial effects of curcumin, its derivatives, and other relevant pharmaceutical formulations on leishmaniasis.

METHODS

The present study was carried out according to the 06-preferred reporting items for systematic reviews and meta-analyses (PRISMA) guideline and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. Some English-language databases including PubMed, Google Scholar, Web of Science, EBSCO, Science Direct, and Scopus were searched for publications worldwide related to antileishmanial effects of curcumin, its derivatives, and other relevant pharmaceutical formulations, without date limitation, to identify all the published articles (in vitro, in vivo, and clinical studies). Keywords included "curcumin", "Curcuma longa", "antileishmanial", "Leishmania", "leishmaniasis", "cutaneous leishmaniasis", "visceral leishmaniasis", "in vitro", and "in vivo".

RESULTS

Out of 5492 papers, 29 papers including 20 in vitro (69.0%), 1 in vivo (3.4%), and 8 in vitro/in vivo (27.6%) studies conducted up to 2020, met the inclusion criteria for discussion in this systematic review. The most common species of the Leishmania parasite used in these studies were L. donovani (n = 13, 44.8%), L. major (n = 10, 34.5%), and L. amazonensis (n = 6, 20.7%), respectively. The most used derivatives in these studies were curcumin (n = 15, 33.3%) and curcuminoids (n = 5, 16.7%), respectively.

CONCLUSION

In the present review, according to the studies in the literature, various forms of drugs based on curcumin and their derivatives exhibited significant in vitro and in vivo antileishmanial activity against different Leishmania spp. The results revealed that curcumin and its derivatives could be considered as an alternative and complementary source of valuable antileishmanial components against leishmaniasis, which had no significant toxicity. However, further studies are required to elucidate this concluding remark, especially in clinical settings.

Exploring Innovative Leishmaniasis Treatment: Drug Targets from Pre-Clinical to Clinical Findings

Leishmaniasis is a group of tropical diseases caused by parasitic protozoa belonging to the genus Leishmania. The disease is categorized in cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL). The conventional treatment is complex and can present high toxicity and therapeutic failures. Thus, there is a continuing need to develop new treatments. In this review, we focus on the novel molecules described in the literature with potential leishmanicidal activity, categorizing them in pre-clinical (in vitro, in vivo), drug repurposing and clinical research.

A comprehensive review of the therapeutic potential of curcumin nanoformulations

Today, due to the prevalence of various diseases such as the novel coronavirus (SARS-CoV-2), diabetes, central nervous system diseases, cancer, cardiovascular disorders, and so on, extensive studies have been conducted on therapeutic properties of natural and synthetic agents. A literature review on herbal medicine and commercial products in the global market showed that curcumin (Cur) has many therapeutic benefits compared to other natural ingredients. Despite the unique properties of Cur, its use in clinical trials is very limited. The poor biopharmaceutical properties of Cur such as short half-life in plasma, low bioavailability, poor absorption, rapid metabolism, very low solubility (at acidic and physiological pH), and the chemical instability in body fluids are major concerns associated with the clinical applications of Cur. Recently, nanoformulations are emerging as approaches to develop and improve the therapeutic efficacy of various drugs. Many studies have shown that Cur nanoformulations have tremendous therapeutic potential against various diseases such as SARS-CoV-2, cancer, inflammatory, osteoporosis, and so on. These nanoformulations can inhibit many diseases through several cellular and molecular mechanisms. However, successful long-term clinical results are required to confirm their safety and clinical efficacy. The present review aims to update and explain the therapeutic potential of Cur nanoformulations.

Nanotechnology-aided diagnosis, treatment and prevention of leishmaniasis

Leishmaniasis is a prevalent parasitic infection belonging to neglected tropical diseases. It is caused by Leishmania protozoan parasites transmitted by sandflies and it is responsible for increased morbidity/mortality especially in low- and middle-income countries. The lack of cheap, portable, easy to use diagnostic tools exhibiting high efficiency and specificity impede the early diagnosis of the disease. Furthermore, the typical anti-leishmanial agents are cytotoxic, characterized by low patient compliance and require long-term regimen and usually hospitalization. In addition, due to the intracellular nature of the disease, the existing treatments exhibit low bioavailability resulting in low therapeutic efficacy. The above, combined with the common development of resistance against the anti-leishmanial agents, denote the urgent need for novel therapeutic strategies. Furthermore, the lack of effective prophylactic vaccines hinders the control of the disease. The development of nanoparticle-based biosensors and nanocarrier-aided treatment and vaccination strategies could advance the diagnosis, therapy and prevention of leishmaniasis. The present review intends to highlight the various nanotechnology-based approaches pursued until now to improve the detection of Leishmania species in biological samples, decrease the side effects and increase the efficacy of anti-leishmanial drugs, and induce enhanced immune responses, specifically focusing on the outcome of their preclinical and clinical evaluation.

Chlorin e6 conjugated chitosan as an efficient photoantimicrobial agent

The development of antibacterial agents with high bacteria-binding capability and antibacterial efficiency is highly desirable. Herein, cationic polysaccharide chitosan (CS) was combined with photosensitizer Chlorin e6 (Ce6) to construct a novel photodynamic antibacterial agent (CS-Ce6 conjugates) for combating gram-positive bacteria Staphylococcus aureus (S. aureus) and gram-negative bacteria Escherichia coli (E. coli). CS-Ce6 conjugates with different degrees of substitution (DS) were synthesized and characterized by a spectroscopic method and organic elemental analysis to understand the relationship between structure and antibacterial effect. CS-Ce6 conjugates revealed good reactive oxygen species (ROS) generation ability and photodynamic antibacterial effect. Meanwhile, they both were positively correlated with DS in the range of 4.81% ~ 11.56% resulting in stronger photodynamic antibacterial ability. These findings highlight that CS-Ce6 conjugates have the potential as an effective photodynamic bactericidal agent in the antibacterial field.

Albalawi A, Alanazi AD, Baharvand P, Moghaddam A, Mahmoudvand H. Chitosan-Based Nanomaterials as Valuable Sources of Anti-Leishmanial Agents: A Systematic Review

BACKGROUND

The current chemotherapy agents against various forms of leishmaniasis have some problems and side effects, including high toxicity, high cost, and the emergence of resistant strains. Here, we aimed to review the preclinical studies (in vitro and in vivo) on the anti-leishmanial activity of chitosan and chitosan-based particles against Leishmania spp.

METHODS

This study was conducted based on the 06-PRISMA guidelines and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. Various English databases such as PubMed, Google Scholar, Web of Science, EBSCO, ScienceDirect, and Scopus were used to find the publications related to the anti-leishmanial effects of chitosan and its derivatives and other pharmaceutical formulations, without a date limitation, to find all the published articles. The keywords included "chitosan", "chitosan nanoparticles", "anti-leishmanial", "Leishmania", "leishmaniasis", "cutaneous leishmaniasis", "visceral leishmaniasis", "in vitro", and "in vivo". The language for data collection were limited to English.

RESULTS

Of 2669 papers, 25 papers, including 7 in vitro (28.0%), 7 in vivo (28.0%), and 11 in vitro/in vivo (44.0%) studies conducted up to 2020 met the inclusion criteria for discussion in this systematic review. The most common species of Leishmania used in these studies were L. major (12, 48.0%), L. donovani (7, 28.0%), and L. amazonensis (4, 16.80%). In vivo, the most used animals were BALB/c mice (11, 61.1%) followed by hamsters (6, 33.3%) and Wistar rats (1, 5.5%), respectively. In vitro, the most used Leishmania form was amastigote (8, 44.4%), followed by promastigote (4, 22.2%), and both forms promastigote/amastigote (6, 33.3%).

CONCLUSION

According to the literature, different types of drugs based on chitosan and their derivatives demonstrated considerable in vitro and in vivo anti-leishmanial activity against various Leishmania spp. Based on the findings of this review study, chitosan and its derivatives could be considered as an alternative and complementary source of valuable components against leishmaniasis with a high safety index. Nevertheless, more investigations are required to elaborate on this result, mainly in clinical settings.

Chitosan-based nanocarriers for encapsulation and delivery of curcumin: A review

To overcome the poor aqueous solubility and bioavailability of curcumin, emphasize its functional features, and broaden its applications in the food and pharmaceutical industries, many nanoscale systems have been widely applied for its encapsulation and delivery. Over many decades, chitosan as a natural biopolymer has been extensively studied due to its polycationic nature, biodegradability, biocompatibility, non-toxicity, and non-allergenic. Various chitosan-based nanocarriers with unique properties for curcumin delivery, including but not limited to, self-assembled nanoparticles, nanocomposites, nanoemulsions, nanotubes, and nanofibers, have been designed. This review focuses on the most-recently reported fabrication techniques of different types of chitosan-based nanocarriers. The functionalities of chitosan in each formulation which determine the physicochemical properties such as surface charge, morphology, encapsulation driving force, and release profile, were discussed in detail. Moreover, the current pharmaceutical applications of curcumin-loaded chitosan nanoparticles were elaborated. The role of chitosan in facilitating the delivery of curcumin and improving the therapeutic effects on many chronic diseases, including cancer, bacterial infection, wound healing, Alzheimer's diseases, inflammatory bowel disease, and hepatitis C virus, were illustrated. Particularly, the recently discovered mechanisms of action of curcumin-loaded chitosan nanoparticles against the abovementioned diseases were highlighted.

Effects of Curcumin and Its Analogues on Infectious Diseases

Infectious diseases (IDs) are life-threatening illnesses, which result from the spread of pathogenic microorganisms such as bacteria, viruses, fungi, and parasites. IDs are a major challenge for the healthcare systems around the world, leading to a wide variety of clinical manifestations and complications. Despite the capability of frontline-approved medications to partially prevent or mitigate the invasion and subsequent damage of IDs to host tissues and cells, problems such as drug resistance, insufficient efficacy, unpleasant side effects, and high expenses stand in the way of their beneficial applications. One strategy is to evaluate currently explored and available bioactive compounds as possible anti-microbial agents. The natural polyphenol curcumin has been postulated to possess various properties including anti-microbial activities. Studies have shown that it possess pleiotropic effects against bacterial- and parasitic-associating IDs including drug-resistant strains. Curcumin can also potentiate the efficacy of available anti-bacterial and anti-parasitic drugs in a synergistic fashion. In this review, we summarize the findings of these studies along with reported controversies of native curcumin and its analogues, alone and in combination, toward its application in future studies as a natural anti-bacterial and anti-parasitic agent.

The advantages of nanomedicine in the treatment of visceral leishmaniasis: between sound arguments and wishful thinking

Introduction: Although life-threatening if left untreated, visceral leishmaniasis (VL) is still a neglected endemic disease in 98 countries worldwide. The number of drugs available is low and few are in clinical trials. In the last decades, efforts have been made on the development of nanocarriers as drug delivery systems to treat VL. Given the preferential intracellular location of the parasite in the liver and spleen macrophages, the rationale is sturdy. In a clinical setting, liposomal amphotericin B displays astonishing cure rates.Areas covered: A literature search was performed through PubMed and Google Scholar. We critically reviewed the main literature highlighting the success of nanomedicine in VL. We also reviewed the hurdles and yet unfulfilled promises rising awareness of potential drawbacks of nanomedicine in VL.Expert opinion: VL is a disease where nanomedicines successes shine through. However, there are a lot of obstacles on the road to developing more efficient strategies such as targeting functionalization, oral formulations, or combined therapies. And those strategies raise many questions.

Nano- and Microformulations to Advance Therapies for Visceral Leishmaniasis

Visceral leishmaniasis (VL) is a deadly, vector-borne, neglected tropical disease endemic to arid parts of the world and is caused by a protozoan parasite of the genus Leishmania. Chemotherapy is the primary treatment for this systemic disease, and multiple potent therapies exist against this intracellular parasite. However, several factors, such as systemic toxicity, high costs, arduous treatment regimen, and rising drug resistance, are barriers for effective therapy against VL. Material-based platforms have the potential to revolutionize chemotherapy for leishmaniasis by imparting a better pharmacokinetic profile and creating patient-friendly routes of administration, while also lowering the risk for drug resistance. This review highlights promising drug delivery strategies and novel therapies that have been evaluated in preclinical models, demonstrating the potential to advance chemotherapy for VL.

Chitosan Contribution to Therapeutic and Vaccinal Approaches for the Control of Leishmaniasis

The control of leishmaniases, a complex parasitic disease caused by the protozoan parasite Leishmania, requires continuous innovation at the therapeutic and vaccination levels. Chitosan is a biocompatible polymer administrable via different routes and possessing numerous qualities to be used in the antileishmanial strategies. This review presents recent progress in chitosan research for antileishmanial applications. First data on the mechanism of action of chitosan revealed an optimal in vitro intrinsic activity at acidic pH, high-molecular-weight chitosan being the most efficient form, with an uptake by pinocytosis and an accumulation in the parasitophorous vacuole of Leishmania-infected macrophages. In addition, the immunomodulatory effect of chitosan is an added value both for the treatment of leishmaniasis and the development of innovative vaccines. The advances in chitosan chemistry allows pharmacomodulation on amine groups opening various opportunities for new polymers of different size, and physico-chemical properties adapted to the chosen routes of administration. Different formulations have been studied in experimental leishmaniasis models to cure visceral and cutaneous leishmaniasis, and chitosan can act as a booster through drug combinations with classical drugs, such as amphotericin B. The various architectural possibilities given by chitosan chemistry and pharmaceutical technology pave the way for promising further developments.

Recent Advances in Polymeric Nanoparticle-Encapsulated Drugs against Intracellular Infections

Polymeric nanocarriers (PNs) have demonstrated to be a promising alternative to treat intracellular infections. They have outstanding performance in delivering antimicrobials intracellularly to reach an adequate dose level and improve their therapeutic efficacy. PNs offer opportunities for preventing unwanted drug interactions and degradation before reaching the target cell of tissue and thus decreasing the development of resistance in microorganisms. The use of PNs has the potential to reduce the dose and adverse side effects, providing better efficiency and effectiveness of therapeutic regimens, especially in drugs having high toxicity, low solubility in the physiological environment and low bioavailability. This review provides an overview of nanoparticles made of different polymeric precursors and the main methodologies to nanofabricate platforms of tuned physicochemical and morphological properties and surface chemistry for controlled release of antimicrobials in the target. It highlights the versatility of these nanosystems and their challenges and opportunities to deliver antimicrobial drugs to treat intracellular infections and mentions nanotoxicology aspects and future outlooks.

Nanoparticles: New agents toward treatment of leishmaniasis

Leishmaniasis is a widespread disease that causes 20,000 to 30,000 deaths annually, making it a major health problem in endemic areas. Because of low-performance medications, drug delivery poses a great challenge for better treatment of leishmaniasis. The present study's purpose was to review the application of nanoparticles as a new method in leishmaniasis treatment. To identify all relevant literature, we searched Web of Sciences, Scopus, PubMed, NCBI, Scielo, and Google Scholar, and profiled studies published between 1986 and 2019. In the present study, we tried to identify different research efforts in different conditions that examined the influence of various nanoparticles on different forms of leishmaniasis. In this way, we could compare their results and obtain a reliable conclusion from the most recent studies on this subject. Our review's results indicate that incorporating nanoparticles with chemical drugs improves the quality, efficiency, and sustainability of drugs and reduces their costs. Finally, considering the use of nanoparticles in the destruction of parasites, their inhibitory effect (making drugs more effective and less harmful), and their utility in making effective vaccines to prevent and fight against parasites, further research on this issue is highly recommended.

Modified solid lipid nanoparticles encapsulated with Amphotericin B and Paromomycin: an effective oral combination against experimental murine visceral leishmaniasis

The development of an effective oral therapeutics is an immediate need for the control and elimination of visceral leishmaniasis (VL). We exemplify the preparation and optimization of 2-hydroxypropyl-β-cyclodextrin (HPCD) modified solid lipid nanoparticles (SLNs) based oral combinational cargo system of Amphotericin B (AmB) and Paromomycin (PM) against murine VL. The emulsion solvent evaporation method was employed to prepare HPCD modified dual drug-loaded solid lipid nanoparticles (m-DDSLNs). The optimized formulations have a mean particle size of 141 ± 3.2 nm, a polydispersity index of 0.248 ± 0.11 and entrapment efficiency for AmB and PM was found to be 96% and 90% respectively. The morphology of m-DDSLNs was confirmed by scanning electron microscopy and transmission electron microscopy. The developed formulations revealed a sustained drug release profile upto 57% (AmB) and 21.5% (PM) within 72 h and were stable at both 4 °C and 25 °C during short term stability studies performed for 2 months. Confocal laser scanning microscopy confirmed complete cellular internalization of SLNs within 24 h of incubation. In vitro cytotoxicity study against J774A.1 macrophage cells confirmed the safety and biocompatibility of the developed formulations. Further, m-DDSLNs did not induce any hepatic/renal toxicities in Swiss albino mice. The in vitro simulated study was performed to check the stability in simulated gastric fluids and simulated intestinal fluids and the release was found almost negligible. The in vitro anti-leishmanial activity of m-DDSLNs (1 µg/ml) has shown a maximum percentage of inhibition (96.22%) on intra-cellular amastigote growth of L. donovani. m-DDSLNs (20 mg/kg × 5 days, p.o.) has significantly (P < 0.01) reduced the liver parasite burden as compared to miltefosine (3 mg/kg × 5 days, p.o.) in L. donovani-infected BALB/c mice. This work suggests that the superiority of as-prepared m-DDSLNs as a promising approach towards the oral delivery of anti-leishmanial drugs.

Formulation, characterization and in vitro anti-leishmanial evaluation of amphotericin B loaded solid lipid nanoparticles coated with vitamin B12-stearic acid conjugate

Despite the advancement of new anti-leishmanials, amphotericin B (AmB) prevails as one of the most potent agent in the treatment of visceral leishmaniasis (VL), a neglected tropical disease affecting mostly poverty ridden and underdeveloped regions of the globe. Nonetheless, many patients display intolerance to parenteral AmB, notably at higher dosages. Also, conventional AmB presents an apparently poor absorption. Therefore, to improve AmB bioavailability and overcome multiple barriers for oral delivery of AmB, we fabricated a promising vitamin B₁₂-stearic acid (VBS) conjugate coated solid lipid nanoparticles (SLNs) encapsulated with AmB (VBS-AmB-SLNs) by a combination of double emulsion solvent evaporation and thermal sensitive hydrogel techniques. VBS-AmB-SLNs showed a particle size of 306.66 ± 3.35 nm with polydispersity index of 0.335 ± 0.08 while the encapsulation efficiency and drug loading was observed to be 97.99 ± 1.6% and 38.5 ± 5.6% respectively. In vitro drug release showed a biphasic release pattern and chemical stability of AmB was ensured against simulated gastrointestinal fluids. Cellular uptake studies confirmed complete internalization of the formulation. Anti-leishmanial evaluation against intramacrophage amastigotes showed an enhanced efficacy of 94% which was significantly (P < 0.01) higher than conventional AmB without showing any toxic effects on J774A.1 cells. VBS-AmB-SLNs could serve as a potential therapeutic strategy against VL.

Drug delivery to macrophages: a review of nano-therapeutics targeted approach for inflammatory disorders and cancer

INTRODUCTION

Macrophages are involved in the normal defense of the body; however, the varying phenotypes of macrophages and imbalance in their ratio lead to the impairment of immune response initiating the production of inflammation. As the role of macrophages in immunological disorders and their surface receptors modulation has already been manifested; hence, macrophages can be exploited to make them a viable candidate for targeted delivery, which was not possible with previously designed conventional therapies for the immune disorders.

AREAS COVERED

Nanotechnology is a promising, clear cut, efficient, and adequate approach for targeting macrophages. Literature addresses the receptors available for targeting and the novel small dimensional therapeutic delivery vehicles to target them along with a brief overview of the role of macrophages in these diseases. Furthermore, the patents based on this idea are also listed.

EXPERT OPINION

Targeted drug delivery to macrophages should take into consideration the plasticity of macrophages and their modulation over time in the diseases. A cost-effective scale-up method of development will further facilitate the clinical trials. Besides, the implementation of safety guidelines to target macrophages and the studies of long-term effects of targeted approaches in humans would highly encourage the clinical outcomes.

A Systematic Literature Review of Curcumin with Promising Antileishmanial Activity

BACKGROUND

Curcumin (CUR) is a bright yellow chemical and it is used as an additive in foods. Recently CUR and its associated bioactive compounds have received much attention in the literature review. The aim of this systematic review is to overview the antileishmanial properties of CUR and its mechanism; perhaps the results of this study will be used for therapeutic and preventive purposes.

METHODS

Following the PRISMA guidelines, international databases were systematically searched for studies published until September 2019. Articles related to the subject were selected and included in this systematic review.

RESULTS

A total of 15 articles met our eligibility criteria. Then, the effect of CUR and its associated bioactive compounds on Leishmania species was evaluated. In most studies, CUR/derivatives were tested on L. major and in vitro condition. Most investigations were conducted on the promastigote rather than the more relevant intracellular amastigote stage. Our results showed that CUR overcomes the inhibitory effect of nitric oxide (NO) on Leishmania parasites.

CONCLUSION

This review indicated that CUR derivatives, instead of CUR alone showed a high potential to serve as an effective herbal drug against leishmaniasis. Moreover, we concluded that the antileishmanial activity of CUR/bioactive compounds is mostly due to increased oxidative stress and apoptosis.

A short review on chemical properties, stability and nano-technological advances for curcumin delivery

Introduction: Curcumin is a polyphenol found in turmeric that is derived from the rhizomes of Curcuma longa. Curcumin has received a worldwide attention due to being a major constituent of the traditional Chinese and Indian holistic systems, and due to its well-documented pharmacological effects against various diseases.Areas covered: In order to provide a better understanding of curcumin's biological activities, its chemical, structural, spectral and photophysical properties should be studied. Also, it is crucial to study the aqueous, spectral, photophysical, photochemical, and thermal stability. Such studies indicated that curcumin suffers from bioavailability problems such as low serum levels, limited tissue distribution, and excessive metabolism which all limit its therapeutic efficacy. This review summarizes different properties of curcumin, its stability, bioavailability problems, and recent nanotechnological approaches with special highlight on nanocapsules for curcumin delivery.Expert opinion: Poor bioavailability of curcumin could be overcome through recently emerging and promising nanotechnological approaches.

Envisioning the innovations in nanomedicine to combat visceral leishmaniasis: for future theranostic application

Visceral leishmaniasis (VL) is a life-threatening parasitic disease affecting impoverished people of the developing world; and much effort has been spent on the early case detection and treatment. However, current diagnostics and treatment options are not sufficient for appropriate surveillance in VL elimination setting. Hence, there is a dire need to develop highly sensitive diagnostics and less toxic effective treatments for proper management of cases and to achieve the sustained disease elimination. Although, promising results have been observed with nanomedicines in leishmaniasis; there are great challenges ahead especially in translating this to clinical setting. This review provides updated progress of nanomedicines in VL, and discussed how these innovations and future directions play vital role in achieving VL elimination.

Ligand decorated chitosan as an advanced nanocarrier for targeted delivery: a critical review

Nontargeted delivery systems present nonspecific delivery, low transfection efficiency and high toxicity. Ligand-conjugated chitosan (CS) nanocarriers have emerged as an outstanding option for achieving active delivery specifically and preferentially to the target sites by exploiting receptors mediated endocytosis. Mannosylated CS nanocarriers have brought tremendous breakthrough in gene therapy and have proven to be an excellent choice for treatment of infectious and inflammatory diseases. Similarly, folate and antibodies-conjugated CS play a significant role in diagnosis and treatment of various cancers. Current evidences obviously propose ligand-decorated CS as an attractive option for diagnosis and treatment of dreadful conditions. In order to bring huge revolution in the field of targeted delivery, challenges associated with these nanocarriers needs to be addressed.