Evaluation of the Photodynamic Therapy with Curcumin on L. braziliensis and L. major Amastigotes

Piperine, quercetin, and curcumin identified as promising natural products for topical treatment of cutaneous leishmaniasis

Leishmania braziliensis (L. braziliensis) causes cutaneous leishmaniasis (CL) in the New World. The costs and the side effects of current treatments render imperative the development of new therapies that are affordable and easy to administer. Topical treatment would be the ideal option for the treatment of CL. This underscores the urgent need for affordable and effective treatments, with natural compounds being explored as potential solutions. The alkaloid piperine (PIP), the polyphenol curcumin (CUR), and the flavonoid quercetin (QUE), known for their diverse biological properties, are promising candidates to address these parasitic diseases. Initially, the in vitro cytotoxicity activity of the compounds was evaluated using U-937 cells, followed by the assessment of the leishmanicidal activity of these compounds against amastigotes of L. braziliensis. Subsequently, a golden hamster model with stationary-phase L. braziliensis promastigote infections was employed. Once the ulcer appeared, hamsters were treated with QUE, PIP, or CUR formulations and compared to the control group treated with meglumine antimoniate administered intralesionally. We observed that the three organic compounds showed high in vitro leishmanicidal activity with effective concentrations of less than 50 mM, with PIP having the highest activity at a concentration of 8 mM. None of the compounds showed cytotoxic activity for U937 macrophages with values between 500 and 700 mM. In vivo, topical treatment with QUE daily for 15 days produced cured in 100% of hamsters while the effectiveness of CUR and PIP was 83% and 67%, respectively. No failures were observed with QUE. Collectively, our data suggest that topical formulations mainly for QUE but also for CUR and PIP could be a promising topical treatment for CL. Not only the ease of obtaining or synthesizing the organic compounds evaluated in this work but also their commercial availability eliminates one of the most important barriers or bottlenecks in drug development, thus facilitating the roadmap for the development of a topical drug for the management of CL caused by L. braziliensis.

Photodynamic therapy of cationic and anionic BSA-curcumin nanoparticles on amastigotes of Leishmania braziliensis and Leishmania major and Leishmania amazonensis

Cutaneous leishmaniasis is a neglected disease prevalent in tropical countries, and conventional treatment can cause several serious side effects. Photodynamic therapy (PDT) can be considered a promising treatment alternative, as it is non-invasive therapy that has no side effects and uses accessible and low-cost substances, such as curcumin. This study evaluated the PDT response with cationic and anionic BSA nanoparticles encapsulated with curcumin in macrophages infected with L. braziliensis, L. major, and L. amazonensis. The nanoparticle system was characterized using a steady-state technique, scanning electron microscopy (SEM) study, and its biological activity was evaluated using macrophage cell lines infected with different Leishmania species. All spectroscopy measurements demonstrated that BSA curcumin (BSACur) has good photophysical properties, and confocal microscopy shows that macrophages and protozoa internalized the nanoparticles. The viability test demonstrated that at low concentrations, such as 0.1, 0.7, and 1.0 µmol. L-1, there was a decrease in cell viability after PDT application. Furthermore, a decrease in the number of parasites recovered was observed in the PDT groups. The results allowed us to conclude that curcumin loaded into BSA nanoparticles may have potential application in drug delivery systems for PDT protocols, demonstrating reduced cell viability at lower concentrations than free curcumin.

Potential of Curcumin in the Management of Skin Diseases

Curcumin is a polyphenolic molecule derived from the rhizoma of Curcuma longa L. This compound has been used for centuries due to its anti-inflammatory, antioxidant, and antimicrobial properties. These make it ideal for preventing and treating skin inflammation, premature skin ageing, psoriasis, and acne. Additionally, it exhibits antiviral, antimutagenic, and antifungal effects. Curcumin provides protection against skin damage caused by prolonged exposure to UVB radiation. It reduces wound healing times and improves collagen deposition. Moreover, it increases fibroblast and vascular density in wounds. This review summarizes the available information on the therapeutic effect of curcumin in treating skin diseases. The results suggest that curcumin may be an inexpensive, well-tolerated, and effective agent for treating skin diseases. However, larger clinical trials are needed to confirm these observations due to limitations in its in vivo use, such as low bioavailability after oral administration and metabolism.

Molecular effects of photodynamic therapy with curcumin on Leishmania major promastigotes

Leishmaniasis is a neglected disease mainly affecting low-income populations. Conventional treatment involves several side effects, is expensive, and, in addition, protozoa can develop resistance. Photodynamic therapy (PDT) is a promising alternative in treating the disease. PDT involves applying light at a specific wavelength to activate a photosensitive compound (photosensitizer, PS), to produce reactive oxygen species (ROS). Curcumin and its photochemical characteristics make it a good candidate for photodynamic therapy. Studies evaluating gene expression can help to understand the molecular events involved in the cell death caused by PDT. In the present study, RNA was extracted from promastigotes from the control and treated groups after applying PDT. RT-qPCR was performed to verify the expression of the putative ATPase beta subunit (ATPS), ATP synthase subunit A (F0F1), argininosuccinate synthase 1 (ASS), ATP-binding cassette subfamily G member 2 (ABCG2), glycoprotein 63 (GP63), superoxide dismutase (FeSODA), and glucose-6-phosphate dehydrogenase (G6PDH) genes (QR). The results suggest that PDT altered the expression of genes that participate in oxidative stress and cell death pathways, such as ATPS, FeSODA, and G6PD. The ATP-F0F1, ASS, and GP63 genes did not have their expression altered. However, it is essential to highlight that other genes may be involved in the molecular mechanisms of oxidative stress and, consequently, in the death of parasites.

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.

In vitro antifungal activity of curcumin mediated by photodynamic therapy on Sporothrix brasiliensis

BACKGROUND

Sporothrix brasiliensis is a pathogenic dimorphic fungus that affects humans and animals causing sporotrichosis. The treatment of this disease with conventional antifungals commonly results in therapeutic failures and resistance. Therefore, this study aimed to evaluate the in vitro effect of curcumin (CUR) mediated by photodynamic therapy (PDT) in its pure state and incorporated into pharmaceutical formulation in gel form, on the filamentous and yeast forms of S. brasiliensis.

METHODS

Cells from both forms of the fungus were treated with pure curcumin (PDT-CUR). For this, CUR concentrations ranging from 0.09 to 50 μM were incubated for 15 min and then irradiated with blue LED at 15 J/cm². Similarly, it was performed with PDT-CUR-gel, at lower concentration with fungistatic action. After, a qualitative and quantitative (colony forming units (CFU)) analysis of the results was performed. Additionally, reactive oxygen species (ROS) were detected by flow cytometry. Results PDT with 0.78 μM of CUR caused a significant reduction (p < 0.05) in cells of the filamentous and yeast form, 1.38 log10 and 1.18 log10, respectively, in comparison with the control. From the concentration of 1.56 μM of CUR, there was a total reduction in the number of CFU (≥ 3 log10). The PDT-CUR-gel, in relation to its base without CUR, presented a significant reduction (p < 0.05) of 0.83 log10 for the filamentous form and for the yeast form, 0.72 log10. ROS release was detected after the PDT-CUR assay, showing that this may be an important pathway of death caused by photoinactivation. Conclusion PDT-CUR has an important in vitro antifungal action against S. brasiliensis strains in both morphologies.

Curcuma longa L. Extract and Photodynamic Therapy are Effective against Candida spp. and Do Not Show Toxicity In Vivo

Radiotherapy induces a higher level of Candida spp. colonization, resulting in oral candidiasis. This study aimed to evaluate the phototransformation potential of the glycolic extract of Curcuma longa (C. longa); the antifungal activity of C. longa, curcumin, and antifungal photodynamic therapy (aPDT) with blue light-emitting diodes "LED" on Candida albicans and Candida tropicalis in vitro; and the toxicity of C. longa and curcumin in Galleria mellonella model. In order to confirm the light absorption capacity of the C. longa extract, its phototransformation potential was evaluated. The antifungal effect of C. longa, curcumin, and aPDT was evaluated over Candida spp. Finally, the toxicity of C. longa and curcumin was evaluated on the Galleria mellonella model. The data were analyzed using the GraphPad Prism 5.0 software considering α = 5%. It was found that C. longa, curcumin, and aPDT using blue LED have an antifungal effect over C. albicans and C. tropicalis. The extract of C. longa 100 mg/mL and curcumin 200 μg/mL do not show toxicity on Galleria mellonella model.

The Natural Alkaloid Tryptanthrin Induces Apoptosis-like Death in Leishmania spp

Leishmaniasis is a vector-borne disease against which there are no approved vaccines, and the treatment is based on highly toxic drugs. The alkaloids consist of a chemical class of natural nitrogen-containing substances with a long history of antileishmanial activity. The present study aimed at determining the antileishmanial activity and in silico pharmacokinetic and toxicological potentials of tryptanthrin alkaloid. The anti-Leishmania amazonensis and anti-L. infantum assays were performed against both promastigotes and intracellular amastigotes. Cellular viability was determined by parasites’ ability to grow (promastigotes) or differentiate (amastigotes) after incubation with tryptanthrin. The mechanisms of action were explored by mitochondrion dysfunction and apoptosis-like death evaluation. For the computational pharmacokinetics and toxicological analysis (ADMET), tryptanthrin was submitted to the PreADMET webserver. The alkaloid displayed anti-promastigote activity against L. amazonensis and L. infantum (IC₅₀ = 11 and 8.0 μM, respectively). Tryptanthrin was active against intracellular amastigotes with IC₅₀ values of 75 and 115 μM, respectively. Mitochondrial membrane depolarization was observed in tryptanthrin-treated promastigotes. In addition, parasites undergoing apoptosis-like death were detected after 18 h of exposure. In silico ADMET predictions revealed that tryptanthrin has pharmacokinetic and toxicological properties similar to miltefosine. The results presented herein demonstrate that tryptanthrin is an interesting drug candidate against leishmaniasis.

Photodynamic therapy for leishmaniasis: Recent advances and future trends

Leishmaniasis has infected more than 12 million people worldwide. This neglected tropical disease, causing 20,000-30,000 deaths per year, is a global health problem. The emergence of resistant parasites and serious side effects of conventional therapies has led to the search for less toxic and non-invasive alternative treatments. Photodynamic therapy is a promising therapeutic strategy to produce reactive oxygen species for the treatment of leishmaniasis. In this regard, natural and synthetic photosensitizers such as curcumin, hypericin, 5-aminolevulinic acid, phthalocyanines, phenothiazines, porphyrins, chlorins and nanoparticles have been applied. In this review, the recent advances on using photodynamic therapy for treating Leishmania species have been reviewed.