An overview of the treatment of cutaneous leishmaniasis

Epoxy-a-lapachone in nanosystem: a prototype drug for leishmaniasis assessed in the binomial BALB/c - Leishmania (Leishmania) amazonensis

This perspective presents and supports arguments for a new formulation of epoxy-α-lapachone loaded microemulsion (ELAP-ME), a nanosystem, as a prototype drug for the treatment of leishmaniasis. The benefits of ELAP as a multitarget compound, with properties that affect key physiological pathways of Leishmania spp. are discussed. ELAP-ME demonstrated efficacy in murine infection models, particularly with the binomial BALB/c-Leishmania (Leishmania) amazonensis. Furthermore, it is proposed that the technological maturity of ELAP-ME be classified as Technology Readiness Level 4 (TLR 4) within the context of innovative drugs for American Cutaneous Leishmaniasis (ACL).

Unusual Unsatisfactory Treatment in Two Patients with Imported Cutaneous Leishmaniasis

Cutaneous leishmaniasis is one of the most commonly diagnosed dermatological condition in travel medicine after diarrhoeal diseases and febrile status. The disease is transmitted by Phlebotomus and Lutzomyia sandflies. It appears in various clinical forms, the most common of which is a painless ulcer with raised edges, usually present on exposed parts of the body on the side where the insect bite occurred. Annually, over a million new cutaneous leishmaniasis (CL) cases are reported globally. We present two cases of affliction, the first occurring in Patient 1, who attempted treatment through the Kambo cleanse in South America, which is considered a toxic, even life-threatening, procedure. It involves the subcutaneous application of a substance dangerous to humans derived from the surface mucus of a frog. Patient 2 applied caustic ointments, a fruitarian diet, and hyperbaric oxygen therapy in a private setting. After initial therapeutic failures caused by the patients' unconventional treatment ideas, the causal treatment effect was satisfactory, demonstrating the efficacy of these treatments in resolving the infection when applied appropriately. Despite the typical CL presentation in both patients, their self-treatment course was unusual. It is worth noting that alternative, sometimes harmful, self-treatment initiatives by patients may be surprising and ineffective. Promoting knowledge about tropical diseases among travellers and medical staff is crucial to improving treatment outcomes.

The first evaluation of the in vitro effects of silver(I)-N-heterocyclic carbene complexes on Encephalitozoon intestinalis and Leishmania major promastigotes

Encephalitozoon intestinalis is an opportunistic microsporidian parasite that primarily infects immunocompromised individuals, such as those with HIV/AIDS or undergoing organ transplantation. Leishmaniasis is responsible for parasitic infections, particularly in developing countries. The disease has not been effectively controlled due to the lack of an effective vaccine and affordable treatment options. Current treatment options for E. intestinalis infection and leishmaniasis are limited and often associated with adverse side effects. There is no previous study in the literature on the antimicrosporidial activities of Ag(I)-N-heterocyclic carbene compounds. In this study, the in vitro antimicrosporidial activities of previously synthesized Ag(I)-N-heterocyclic carbene complexes were evaluated using E. intestinalis spores cultured in human renal epithelial cell lines (HEK-293). Inhibition of microsporidian replication was determined by spore counting. In addition, the effects of the compounds on Leishmania major promastigotes were assessed by measuring metabolic activity or cell viability using a tetrazolium reaction. Statistical analysis was performed to determine significant differences between treated and control groups. Our results showed that the growth of E. intestinalis and L. major promastigotes was inhibited by the tested compounds in a concentration-dependent manner. A significant decrease in parasite viability was observed at the highest concentrations. These results suggest that the compounds have potential anti-microsporidial and anti-leishmanial activity. Further research is required to elucidate the underlying mechanisms of action and to evaluate the efficacy of the compounds in animal models or clinical trials.

N6-methyltubercidin gives sterile cure in a cutaneous Leishmania amazonensis mouse model

Leishmania is a trypanosomatid parasite that causes skin lesions in its cutaneous form. Current therapies rely on old and expensive drugs, against which the parasites have acquired considerable resistance. Trypanosomatids are unable to synthesize purines relying on salvaging from the host, and nucleoside analogues have emerged as attractive antiparasitic drug candidates. 4-Methyl-7-β-D-ribofuranosyl-7H-pyrrolo[2,3-d]pyrimidine (CL5564), an analogue of tubercidin in which the amine has been replaced by a methyl group, demonstrates activity against Trypanosoma cruzi and Leishmania infantum. Herein, we investigated its in vitro and in vivo activity against L. amazonensis. CL5564 was 6.5-fold (P = 0.0002) more potent than milteforan™ (ML) against intracellular forms in peritoneal mouse macrophages, and highly selective, while combination with ML gave an additive effect. These results stimulated us to study the activity of CL5564 in mouse model of cutaneous Leishmania infection. BALB/c female and male mice infected by L. amazonensis treated with CL5564 (10 mg kg−1, intralesional route for five days) presented a >93% reduction of paw lesion size likely ML given orally at 40 mg kg−1, while the combination (10 + 40 mg kg−1 of CL5564 and ML, respectively) caused >96% reduction. The qPCR confirmed the suppression of parasite load, but only the combination approach reached 66% of parasitological cure. These results support additional studies with nucleoside derivatives.

Comparing the efficacy of fluconazole and cryotherapy Versus cryotherapy alone on treating cutaneous leishmaniasis: a triple-blind randomized clinical trial

OBJECTIVE

Cutaneous Leishmaniasis (CL) is one of the highly prevalent endemic diseases in the Middle East. The disease is a complex skin infection imposing a heavy burden on many developing countries. This study aimed to evaluate the impact of adding oral fluconazole to topical cryotherapy on the treatment efficacy and time to achieve complete recovery of CL lesions.

METHOD

This triple-blind randomized clinical trial included 52 participants with CL. Participants were allocated to receive either weekly cryotherapy with liquid nitrogen and oral fluconazole at a dose of 6 mg/kg daily at a maximum of 400 mg for 6 weeks as the interventional arm or weekly cryotherapy with liquid nitrogen plus the placebo for the same period of 6 weeks as the control arm.

RESULTS

Fifty-two eligible participants enrolled the study, with a CL lesion count of 1 to 8 (mean 1.96), and served as the interventional (n = 28) and control (n = 24) arms. The trend of the mean surface area of the lesions was significantly decreasing in both arms (P < 0.001), with no statistically significant difference between arms (P = 0.133) or all assessed time point pairwise comparisons (P > 0.05). There was no significant difference between the treatment arms in terms of the end-point recovery status (P = 0.491) or the frequency of post-treatment secretion (P = 0.437). No adverse effect was observed.

CONCLUSION

Despite a slightly higher reduction in the lesion surface in the cryotherapy and fluconazole treatment arm, the addition of fluconazole did not provide statistically significant therapeutic value to cryotherapy in the treatment of CL. However, with adjustment for the initial lesion size, the efficacy of the regimen in the interventional arm was more pronounced, though it was still insignificant.

Beyond traditional medications: exploring novel and potential inhibitors of trypanothione reductase (LmTr) of Leishmania parasites

The trypanothione reductase enzyme, which neutralizes the reactive oxygen species produced inside the macrophages to kill the parasites, is one of the evasion strategies Leishmania uses to survive inside the cells. The vitality of the parasite depends on Leishmania major trypanothione reductase (LmTr), a NADPH-dependent flavoprotein oxidoreductase essential for thiol metabolism. Since this enzyme is distinct and lacking in humans, we focused on it in our study to screen for new inhibitors to combat leishmaniasis. Using the I-TASSER server, a three-dimensional model of LmTr was generated. The Autodock vina program was used in high-throughput virtual screening of the ZINC database. The top seven molecules were ranked according to their binding affinity. The compounds with the highest binding affinities and the right number of hydrogen bonds were chosen. These compounds may be effective at inhibiting the target enzyme's (LmTr) activity, making them new leishmaniasis treatments. These compounds may serve as a useful starting point for a hit-to-lead approach in the quest for new anti-Leishmania drugs that are more efficient and less cytotoxic. The average node degree is 5.09, the average local clustering coefficient is 0.868, and the PPI enrichment p-value is 8.9e-06, indicating that it is sufficiently connected to regulate the network. TRYR (LmTr protein) also interacts physically with ten additional proteins in the pathogenesis network. The findings of the study indicated that successfully suppressing the LmTr protein in vitro and in vivo may finally result in regulating the L. major pathogenesis.Communicated by Ramaswamy H. Sarma.

Anti-leishmanial effects of Eryngium planum and Ecbilliun elaterum methanolic extract against Leishmania major

Leishmaniasis is a vector-borne disease, one of the most important neglected tropical diseases. Existing anti-leishmanial treatments are not effective for a long time and associated with toxic side effects so searching for a new, effective and safe alternative treatments against infectious diseases is greatly needed. This study is aimed to assess the leishmaniacidal effects of methanolic extracts of Eryngium planum (E. planum) and Ecbilliun elaterum (E. elaterum) on Leishmania major (L. major), In vitro. The selected plants were collected from northern areas of Iran. The methanolic extract from the aerial parts of plants were prepared using maceration methods. GC- Mass analysis was used to determine the compounds of the plants. Promastigotes of L. major was cultured in RPMI-1640 medium and the anti-leishmanial and cytotoxicity effects of extracts at concentrations of 100, 200, 400 and 800 µg/ml were assessed using MTT assay. The data obtained from gas chromatography revealed that α-Pinene, Caryophyllene oxide, β-Caryophyllene, Bicyclogermacrene and α-Bisabolol are the main compounds extracted from E. planum and α-Pinene, Germacrene D, Caryophyllene oxide, γ-Eudesmol and α-Bisabolol are the main components of E. elaterum. The results of MTT Assay revealed that E. planum at concentrations of 800 µg/ml after 24 h at 400 µg/ml after 48 h and the E. elaterium at concentrations of 800 µg/ml after 48 h at 400 µg/ml after 72 h had similar anti-leishmanial effects to the positive control. These results indicated that E. planum and E. elaterum are the potential sources for the discovery of novel anti-leishmanial treatments.

The Prospects of Phytomedicines and Nanomedicines to Treat Leishmaniasis: A Comprehensive Review

The global shift in lifestyle has prompted health agencies to redirect their focus from poverty-related diseases to the emergence of lifestyle diseases prevalent in privileged regions. As a result, these diseases have been labeled as "neglected diseases," receiving limited research attention, funding, and resources. Neglected Tropical Diseases (NTDs) encompass a diverse group of vector-borne protozoal diseases that are prevalent in tropical areas worldwide. Among these NTDs is leishmaniasis, a disease that affects populations globally and manifests as skin abnormalities, internal organ involvement, and mucous-related abnormalities. Due to the lack of effective and safe medicines and vaccines, it is crucial to explore alternative resources. Phytomedicine, which comprises therapeutic herbal constituents with anti-leishmanial properties, holds promise but is limited by its poor physicochemical properties. The emerging field of nanomedicine has shown remarkable potential in revitalizing the anti-leishmanial efficacy of these phytoconstituents. In this investigation, we aim to highlight and discuss key plant constituents in combination with nanotechnology that have been explored in the fight against leishmaniasis.

Cheminformatics-based discovery of new organoselenium compounds with potential for the treatment of cutaneous and visceral leishmaniasis

Leishmaniasis affects more than 12 million humans globally and a further 1 billion people are at risk in leishmaniasis endemic areas. The lack of a vaccine for leishmaniasis coupled with the limitations of existing anti-leishmanial therapies prompted this study. Cheminformatic techniques are widely used in screening large libraries of compounds, studying protein-ligand interactions, analysing pharmacokinetic properties, and designing new drug molecules with great speed, accuracy, and precision. This study was undertaken to evaluate the anti-leishmanial potential of some organoselenium compounds by quantitative structure-activity relationship (QSAR) modeling, molecular docking, pharmacokinetic analysis, and molecular dynamic (MD) simulation. The built QSAR model was validated (R2train = 0.8646, R2test = 0.8864, Q2 = 0.5773) and the predicted inhibitory activity (pIC50) values of the newly designed compounds were higher than that of the template (Compound 6). The new analogues (6a, 6b, and 6c) showed good binding interactions with the target protein (Pyridoxal kinase, PdxK) while also presenting excellent drug-likeness and pharmacokinetic profiles. The results of density functional theory, MD simulation, and molecular mechanics generalized Born surface area (MM/GBSA) analyses suggest the favourability and stability of protein-ligand interactions of the new analogues with PdxK, comparing favourably well with the reference drug (Pentamidine). Conclusively, the newly designed compounds could be synthesized and tested experimentally as potential anti-leishmanial drug molecules.Communicated by Ramaswamy H. Sarma.

Field-Deployable Treatments For Leishmaniasis: Intrinsic Challenges, Recent Developments and Next Steps

Leishmaniasis is a neglected tropical disease endemic primarily to low- and middle-income countries, for which there has been inadequate development of affordable, safe, and efficacious therapies. Clinical manifestations of leishmaniasis range from self-healing skin lesions to lethal visceral infection with chances of relapse. Although treatments are available, secondary effects limit their use outside the clinic and negatively impact the quality of life of patients in endemic areas. Other non-medicinal treatments, such as thermotherapies, are limited to use in patients with cutaneous leishmaniasis but not with visceral infection. Recent studies shed light to mechanisms through which Leishmania can persist by hiding in cellular safe havens, even after chemotherapies. This review focuses on exploring the cellular niches that Leishmania parasites may be leveraging to persist within the host. Also, the cellular, metabolic, and molecular implications of Leishmania infection and how those could be targeted for therapeutic purposes are discussed. Other therapies, such as those developed against cancer or for manipulation of the ferroptosis pathway, are proposed as possible treatments against leishmaniasis due to their mechanisms of action. In particular, treatments that target hematopoietic stem cells and monocytes, which have recently been found to be necessary components to sustain the infection and provide a safe niche for the parasites are discussed in this review as potential field-deployable treatments against leishmaniasis.

When Combined with Pentamidine, Originally Ineffective Linezolid Becomes Active in Carbapenem-Resistant Enterobacteriaceae

The increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE) and their biofilm-relevant infections pose a threat to public health. The drug combination strategy provides a new treatment option for CRE infections. This study explored the synergistic antibacterial, antibiofilm activities as well as the in vivo efficacy against CRE of pentamidine combined with linezolid. This study further revealed the possible mechanisms underlying the synergy of the combination. The checkerboard and time-kill assays showed that pentamidine combined with linezolid had significant synergistic antibacterial effects against CRE strains (9/10). Toxicity assays on mammal cells (mouse RAW264.7 and red blood cells) and on Galleria mellonella confirmed that the concentrations of pentamidine and/or linezolid that were used were relatively safe. Antibiofilm activity detection via crystal violet staining, viable bacteria counts, and scanning electron microscopy demonstrated that the combination enhanced the inhibition of biofilm formation and the elimination of established biofilms. The G. mellonella infection model and mouse thigh infection model demonstrated the potential in vivo efficacy of the combination. In particular, a series of mechanistic experiments elucidated the possible mechanisms for the synergy in which pentamidine disrupts the outer membranes, dissipates the membrane potentials, and devitalizes the efflux pumps of CRE, thereby facilitating the intracellular accumulation of linezolid and reactive oxygen species (ROS), which ultimately kills the bacteria. Taken together, when combined with pentamidine, which acts as an outer membrane permeabilizer and as an efflux pump inhibitor, originally ineffective linezolid becomes active in CRE and exhibits excellent synergistic antibacterial and antibiofilm effects as well as a potential therapeutic effect in vivo on CRE-relevant infections. IMPORTANCE The multidrug resistance and biofilm formation of Gram-negative bacteria (GNB) may lead to incurable "superbug" infections. Drug combinations, with the potential to augment the original treatment ranges of drugs, are alternative treatment strategies against GNB. In this study, the pentamidine-linezolid combination showed notable antibacterial and antibiofilm activity both in vitro and in vivo against the problem carbapenem-resistant Enterobacteriaceae (CRE). Pentamidine is often used as an antiprotozoal and antifungal agent, and linezolid is a defensive Gram-positive bacteria (GPB) antimicrobial. Their combination expands the treatment range to GNB. Hence, the pentamidine-linezolid pair may be an effective treatment for complex infections that are mixed by GPB, GNB, and even fungi. In terms of mechanism, pentamidine inhibited the outer membranes, membrane potentials, and efflux pumps of CRE. This might be a universal mechanism by which pentamidine, as an adjuvant, potentiates other drugs, similar to linezolid, thereby having synergistic antibacterial effects on CRE.

Biochemical characterization and assessment of leishmanicidal effects of a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom (CollinLA AO-I)

This study reports the isolation of CollinLAAO-I, a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom, its biochemical characterization and leishmanicidal potential in Leishmania spp. CollinLAAO-I (63.1 kDa) was successfully isolated with high purity using two chromatographic steps and represents 2.5% of total venom proteins. CollinLAAO-I displayed high enzymatic activity (4262.83 U/mg/min), significantly reducing after 28 days. The enzymatic activity of CollinLAAO-I revealed higher affinity for hydrophobic amino acids such as L-leucine, high enzymatic activity in a wide pH range (6.0-10.0), at temperatures from 0 to 25 °C, and showed complete inhibition in the presence of Na⁺ and K⁺. Cytotoxicity assays revealed IC₅₀ of 18.49 and 11.66 μg/mL for Leishmania (L.) amazonensis and Leishmania (L.) infantum, respectively, and the cytotoxicity was completely suppressed by catalase. CollinLAAO-I significantly increased the intracellular concentration of reactive oxygen species (ROS) and reduced the mitochondrial potential of both Leishmania species. Furthermore, CollinLAAO-I decreased the parasite capacity to infect macrophages by around 70%, indicating that even subtoxic concentrations of CollinLAAO-I can interfere with Leishmania vital processes. Thus, the results obtained for CollinLAAO-I provide important support for developing therapeutic strategies against leishmaniasis.

Leishmaniasis: Recent epidemiological studies in the Middle East

Leishmaniasis, one of the most neglected tropical diseases (NTDs), is the third most important vector-borne disease worldwide. This disease has a global impact and severity of the infection and is greatest in the Middle East. The agent of infection is a protozoan parasite of the genus, Leishmania, and is generally transmitted by blood-sucking female sandflies. In humans, there are three clinical forms of infection: (1) cutaneous (CL), (2) mucocutaneous (ML), and (3) visceral leishmaniasis (VL). This review aims to discuss the current epidemiological status of leishmaniasis in Saudi Arabia, Iraq, Syria, and Yemen with a consideration of treatment options. The elevated risk of leishmaniasis is influenced by the transmission of the disease across endemic countries into neighboring non-infected regions.

Capparis spinosa inhibits Leishmania major growth through nitric oxide production in vitro and arginase inhibition in silico

Cutaneous leishmaniasis is an infectious disease, considered as a major public health problem in different regions of the world. The current treatments are limited due to their toxicity and treatment failures, which have increased the search for new substances of natural origin to control this infection. Capparis spinosa is an important medicinal plant, rich in biochemical compounds with a broad range of activities including antimicrobial effects. Nevertheless, more investigations are still needed to determine its effect on Leishmania parasites. This study aimed to evaluate the effect of C. spinosa' extracts on Leishmania major promastigotes and amastigotes growth as well as on L-arginine metabolic pathways, especially the production of leishmanicidal molecules such as nitric oxide. Our results showed that C. spinosa' methanolic and aqueous extracts contained polyphenols and flavonoids at different concentrations. The methanolic extract of C. spinosa, compared to the aqueous extract, showed significantly higher amounts of total polyphenols (21.23 ± 1.08) mg GAE/g of dw (P < 0.05), as well as a higher antioxidant activity evaluated respectively by Reducing Power and DPPH (EC₅₀: 0.31 ± 0.02 and 7.69 ± 1.28) mg/ml. Both extracts significantly inhibited L. major promastigotes and intra-macrophagic amastigotes growth in vitro in a dose-dependent manner (P < 0.001) and induced NO production not only in Leishmania-infected macrophages but also in uninfected macrophages, without showing any cytotoxicity in vitro. Furthermore, in silico docking studies showed that C. spinosa compounds identified by RP-HPLC exhibited inhibitory activity against the arginase enzyme. The leishmanicidal effect of C. spinosa may be due to its phenolic content and its mechanism of action may be mediated by an increase in NO production and by the inhibition of arginase enzyme in silico. These findings support the hypothesis that C. spinosa might be a valuable source of new biomolecules for leishmaniasis treatment.

In vitro and in vivo study on antiprotozoal activity of calcium oxide (CaO) and magnesium oxide (MgO) nanoparticles on promastigote and amastigote forms of Leishmania major

BACKGROUND

Currently, anti-leishmanial drugs have been developed. However, the available compounds have several side effects such as drug resistance and toxicity that cause some limitation for use. The development of nanoparticles (NPs) use in biological research and the proven effectiveness of CaONPs and MgONPs on bacteria and fungi, along with the lack of information about its antileishmanial effects, have motivated this study. CaO and MgONPs possess considerable antibacterial effects because of their alkalinity and active oxygen species. This study has taken into account the impacts of these two NPs on the L. major in vitro and in vivo.

METHODS

To evaluate the antileishmanial activity of NPs, the cytotoxic effect of CaONPs, MgONPs, and MgOCaONPs against L. major amastigotes, promastigotes, as well as macrophages, was evaluated using counting or MTT assay. The possible apoptosis of L. major by CaONPs, MgONPs, and MgOCaONPs was evaluated via flow cytometry assay. For in vivo study, BALB/c mice were allocated to five groups and the lesions of infected mice with L. major promastigotes were treated with a 200 μg/mL concentration CaONPs, MgONPs, and MgOCaONPs, then the mice underwent a 4-week follow-up to examine the wound diameter and survival rates.

RESULTS

The XRD-pattern related to CaONPs and MgONPs indicating the cubic phase and Rocksalt cubic structures. According the effects of nanoparticle on promastigotes the IC₅₀ values of CaONPs, MgONPs, and MgOCaONPs within 72 h were 7.9 ug/mL, 10.3 ug/mL, and 8.0 ug/mL respectively. CaONPs, MgONPs, and MgOCaONPs induced apoptosis in about 7.8%, 53.57%, and 12.8% of promastigotes. All mice presented lesions. MgONPs was the most effective in reducing the size of the lesions.

CONCLUSION

According to the results of the present research, MgONPs and CaONPs showed good in vitro and in vivo effects on L. major promastigotes and intracellular amastigotes especially MgONPs, and also it seems that MgONPs are applicable in Leishmania infection treatment due to their potential antileishmanial effects.

Evaluation of Pharmacokinetic and Toxicological Parameters of Arnica Tincture after Dermal Application In Vivo

Cutaneous leishmaniasis (CL) is classified as a neglected tropical disease by the World Health Organization. As the standard drugs for the treatment of this disease suffer from severe unwanted effects, new effective and safe therapeutic options are required. In our previous work, Arnica tincture showed promising antileishmanial effects in vitro and in vivo. For the potential treatment of human CL patients with Arnica tincture, data on the pharmacokinetic properties of the bioactive, antileishmanial compounds (the sesquiterpene lactone (STL) helenalin and its derivatives) are needed. Therefore, we studied the in vivo absorption of the bioactive compounds after the dermal application of Arnica tincture in rats. Moreover, we analyzed the blood plasma, urine, and feces of the animals by ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). Although the majority (84%) of the applied STLs (1.0 mg) were absorbed, the concentrations in the plasma, urine, and feces were below the limit of detection (0.3 ng/mL) in the samples for UHPLC-HRMS analysis. This result may be explained by extensive metabolism and slow permeation accompanied by the accumulation of STLs in the skin, as described in our previous work. Accordingly, the plasma concentration of STLs after the topical application of Arnica tincture was very far from a dose where toxicity could be expected. Additionally, tests for corrosive or irritant activity as well as acute and repeated-dose dermal toxicity did not show any positive results after the administration of the amounts of Arnica tincture that would be needed for the treatment of CL. Consequently, in the treatment of CL patients with Arnica tincture, no toxic effects are expected, other than the known sensitization potential of the STLs.

HAS 1: A natural product from soil-isolated Streptomyces species with potent activity against cutaneous leishmaniasis caused by Leishmania tropica

Cutaneous Leishmaniasis (CL) is a neglected tropical disease, classified by the World Health Organization (WHO) as one of the most unrestrained diseases. The Syrian war and the significant displacement of refugees aggravated the spread of this ailment into several neighboring countries in the Eastern Mediterranean Region (EMR). In Syria, Leishmania tropica is identified as one of the most aggressive and endemic identified species, causing localized or generalized lesions, often chronic or relapsing. Pentavalent antimonial drugs are currently used as first line treatment against CL. Nonetheless, these drugs exhibit several limitations, including the repetitive painful injections, high cost, poor availability, and mainly systemic toxicity. Besides, the emergence of acquired parasitic resistance hinders their potency, stressing the need for new therapies to combat CL. Natural products (NPs) epitomize a valuable source in drug discovery. NPs are secondary metabolites (SMs) produced by plants, sponges, or a wide variety of organisms, including environmental microorganisms. The EMR is characterized by its immense biodiversity, yet it remains a relatively untapped area in drug discovery. NPs of the region were explored over the last 2 decades, but their discoveries lack biogeographical diversity and are limited to the Red Sea. Here, we isolated previously uncultured environmental soil-dwelling Streptomyces sp. HAS1, from Hasbaya region in southeast Lebanon. When fermented in one of our production media named INA, HAS1 produced a crude extract with significant potency against a clinical Leishmania tropica isolate. Using bio-guided fractionation, the bioactive compound was purified and the structure was elucidated by NMR and LC-HRMS. Our findings establish NPs as strong candidates for treating Leishmania tropica and further dwells on the importance of these natural sources to combat microbial infections.

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.

Current and future strategies against cutaneous parasites

Cutaneous parasites are identified by their specific cutaneous symptoms which are elicited based on the parasite's interactions with the host. Standard anti-parasitic treatments primarily focus on the use of specific drugs to disrupt the regular function of the target parasite. In cases where secondary infections are induced by the parasite itself, antibiotics may also be used in tandem with the primary treatment to deal with the infection. Whilst drug-based treatments are highly effective, the development of resistance by bacteria and parasites, is increasingly prevalent in the modern day, thus requiring the development of non-drug based anti-parasitic strategies. Cutaneous parasites vary significantly in terms of the non-systemic methods that are required to deal with them. The main factors that need to be considered are the specifically elicited cutaneous symptoms and the relative cutaneous depth in which the parasites typically reside in. Due to the various differences in their migratory nature, certain cutaneous strategies are only viable for specific parasites, which then leads to the idea of developing an all-encompassing anti-parasitic strategy that works specifically against cutaneous parasites. The main benefit of this would be the overall time saved in regards to the period that is needed for accurate diagnosis of parasite, coupled with the prescription and application of the appropriate treatment based on the diagnosis. This review will assess the currently identified cutaneous parasites, detailing their life cycles which will allow for the identification of certain areas that could be exploited for the facilitation of cutaneous anti-parasitic treatment.

A case of a verrucous and pseudotumoral mass on the leg that resolved with cryotherapy

Various clinical forms of cutaneous leishmaniasis can be encountered such as: ulcerated, lupoïd, sporotrichoïd and other rare forms (eczematiform, erysipeloid, psoriasiform, verrucous, and pseudotumoral). We report an atypical presentation of verrucous and pseudotumoral cutaneous leishmaniasis that resolved following a course of cryotherapy.

The effects of medicinal herbs and marine natural products on wound healing of cutaneous leishmaniasis: A systematic review

This study aimed to investigate the effects of medicinal herbs and marine natural products on wound healing of cutaneous leishmaniasis. To carry out this literature review, the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) instructions were used. Articles on the potential of medicinal plants and natural substances of marine origin against wound healing of cutaneous leishmaniasis were explored. The scientific databases considered were PubMed, Science Direct, Google Scholar, Web of Science, Scopus, and SpringerLink. The scientific documents collected were mainly scientific articles, books, book chapters, and doctoral thesis. The research considered 73 manuscripts published in the period from 1990 to 2020. From all the data collected, it appears that the scientific literature is rich in medicinal herbs and marine products to be valorized in the wound healing of cutaneous leishmaniasis. We have identified 15 medicinal plants traditionally used in the management of healing or ulcer of cutaneous leishmaniasis, 32 medicinal plants whose efficacy has been demonstrated in vitro or in vivo against cutaneous leishmaniasis, 5 marine products active against cutaneous leishmaniasis. It is also clear that the option of medicinal herbs/marine products in the management of cutaneous leishmaniasis is less expensive and allows to avoid the side effects of conventional products. It is necessary to encourage the development of dermatological topicals for the management of cutaneous leishmaniasis based on the data collected. In vivo research should be intensified on medicinal herbs traditionally used in wound healing of cutaneous leishmaniasis.