Photochemical inhibition of Trichophyton rubrum by different compoundings of 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.

Dual Action of Curcumin as an Anti- and Pro-Oxidant from a Biophysical Perspective

Curcumin, a natural polyphenol widely used as a spice, colorant and food additive, has been shown to have therapeutic effects against different disorders, mostly due to its anti-oxidant properties. Curcumin also reduces the efficiency of melanin synthesis and affects cell membranes. However, curcumin can act as a pro-oxidant when blue light is applied, since upon illumination it can generate singlet oxygen. Our review aims to describe this dual role of curcumin from a biophysical perspective, bearing in mind its concentration, bioavailability-enhancing modifications and membrane interactions, as well as environmental conditions such as light. In low concentrations and without irradiation, curcumin shows positive effects and can be recommended as a beneficial food supplement. On the other hand, when used in excess or irradiated, curcumin can be toxic. Therefore, numerous attempts have been undertaken to test curcumin as a potential photosensitizer in photodynamic therapy (PDT). At that point, we underline that curcumin-based PDT is limited to the treatment of superficial tumors or skin and oral infections due to the weak penetration of blue light. Additionally, we conclude that an increase in curcumin bioavailability through the using nanocarriers, and therefore its concentration, as well as its topical use if skin is exposed to light, may be dangerous.

Curcumin-Containing Polyphosphazene Nanodrug for Anti-Inflammation and Nerve Regeneration to Improve Functional Recovery After Spinal Cord Injury

The microenvironment of excessive inflammation and the activation of apoptotic signals are primary barriers to neurological recovery following spinal cord injury (SCI). Thus, long-lasting anti-inflammation has become an effective strategy to navigate SCI. Herein, a curcumin (CUR)-containing nanosystem (FCTHPC) with high drug loading efficiency was reported via assembling hydrophobic CUR into cross-linked polyphosphazene (PPZ), and simultaneous loading and coordinating with porous bimetallic polymers for greatly enhanced the water-solubility and biocompatibility of CUR. The nanosystem is noncytotoxic when directing its biological activities. By inhibiting the expression of pro-inflammatory factors (IL-1β, TNF-α and IL-6) and apoptotic proteins (C-caspase-3 and Bax/Bcl-2), which may be accomplished by activating the Wnt/β-catenin pathway, the versatile FCTHPC can significantly alleviate the damage to tissues and cells caused by inflammation and apoptosis in the early stage of SCI. In addition, the long-term in vivo studies had demonstrated that FCTHPC could effectively inhibit the formation of glial scars, and simultaneously promote nerve regeneration and myelination, leading to significant recovery of spinal cord function. This study emphasises the promise of the biocompatible CUR-based nanosystem and provides a fresh approach to effectively treat SCI.

In vitro evaluation of photodynamic activity of methylene blue against Trichophyton verrucosum azole-susceptible and -resistant strains

The intense search for the "Holy Grail" of antifungal therapy can be observed today. The searches are not limited only to discovery of potential antifungal drugs, but also new therapeutic strategies involving the use of chemosensitizers to achieve synergistic effect or physicochemical factors inducing stress conditions in fungal cells. In this study was examined in vitro effectiveness of photodynamic antifungal strategy with methylene blue using a light beam with a wavelength equal to 635 nm toward the Trichophyton verrucosum susceptible and itraconazole- and/or fluconazole-resistant strains. Methylene blue used at concentration equal to 5 μg/mL and in the presence of 40 J/cm² of light energy showed fungicidal effect toward the susceptible strains. However, for azole-resistant isolates, only the energy dose equal to 60 J/cm² at 5 μg/mL of methylene blue allowed to kill the pathogen. This study confirms that methylene blue induced by red light has a definite inhibitory effect on zoophilic dermatophytes.

Aloe-emodin-mediated antimicrobial photodynamic therapy against dermatophytosis caused by Trichophyton rubrum

Trichophyton rubrum is responsible for the majority of dermatophytosis. Current systemic and topical antifungals against dermatophytosis are often tedious and sometimes unsatisfactory. Antimicrobial photodynamic therapy (aPDT) is a non‐invasive alternative suitable for the treatment of superficial fungal infections. This work investigated the photodynamic inactivation efficacy and effects of aloe‐emodin (AE), a natural photosensitizer (PS) against T. rubrum microconidia in vitro, and evaluated the treatment effects of AE‐mediated aPDT for T. rubrum‐caused tinea corporis in vivo and tinea unguium ex vivo. The photodynamic antimicrobial efficacy of AE on T. rubrum microconidia was evaluated by MTT assay. The inhibition effect of AE‐mediated aPDT on growth of T. rubrum was studied. Intracellular location of AE, damage induced by AE‐mediated aPDT on cellular structure and surface of microconidia and generation of intracellular ROS were investigated by microscopy and flow cytometry. The therapeutic effects of AE‐mediated aPDT against dermatophytosis were assessed in T. rubrum‐caused tinea corporis guinea pig model and tinea unguium ex vivo model. AE‐mediated aPDT effectively inactivated T. rubrum microconidia in a light energy dose‐dependent manner and exhibited strong inhibitory effect on growth of T. rubrum. Microscope images indicated that AE is mainly targeted to the organelles and caused damage to the cytoplasm of microconidia after irradiation through generation of abundant intracellular ROS. AE‐mediated aPDT demonstrated effective therapeutic effects for T. rubrum‐caused tinea corporis on guinea pig model and tinea unguium in ex vivo model. The results obtained suggest that AE is a potential PS for the photodynamic treatment of dermatophytosis caused by T. rubrum, but its permeability in skin and nails needs to be improved.

Different susceptibility of spores and hyphae of Trichophyton rubrum to methylene blue mediated photodynamic treatment in vitro

BACKGROUND

In recent years, methylene blue mediated-photodynamic therapy (MB-PDT) has proved to be an effective inhibitor to a variety of microorganisms, including Trichophyton rubrum, the most common dermatophyte worldwide. However, previous studies mainly focused on the spore form of T rubrum, but rarely on its hyphal form, although the latter is the main pathogenic form of T rubrum in vivo.

OBJECTIVE

To investigate the inhibitory effect of MB-PDT on T rubrum in different growth phases in vitro.

METHODS

The suspensions of spores and hyphae obtained from T rubrum (ATCC28188) were prepared, respectively, incubated with MB solution (0.15-40 μg/mL) and irradiated with 635 nm red light. Varied light energy and MB concentration were used. The specimen in the absence of light exposure or/and MB served as controls. MIC determination, colony counts and MTT assay were employed to evaluate the antifungal effect of MB-PDT.

RESULTS

The MICs of MB-PDT for hyphae and spores of T. rubrum were 6.300 ± 1.072 μg/mL and 1.984 ± 1.072 μg/mL, respectively, at a fixed light dose of 60 J/cm² . CFU counts gave the minimum critical combinations of MB concentration and light dose to achieve 100% inhibitory rate. For hyphae, they were 5 μg/mL + 100 J/cm² or 10 μg/mL + 60 J/cm² . For spores, they were 1.25 μg/mL + 40 J/cm² or 5 μg/mL + 20 J/cm² . The outcomes of MTT assay were consistent with those of CFU counts, but less accurate.

CONCLUSION

MB-PDT is a potent inhibitor to both spores and hyphae of T. rubrum in vitro, and the spores are more sensitive to it. Its antifungal efficacy is positively correlated with the concentration of MB and light dose.

Clinical isolates of Trichophyton rubrum are completely inhibited by photochemical treatment with a γ-cyclodextrin formulation of curcuminoids

INTRODUCTION

It was shown previously that dermatophytes can markedly be inhibited by a photochemical treatment with curcumin. This kind of photo-inactivation needs to be improved, however, because curcumin is poorly water-soluble. Therefore, a new water-soluble γ-cyclodextrin formulation of curcuminoids was tested for its photochemical inactivation of Trichophyton (T.) rubrum.

MATERIALS AND METHODS

Conidia were harvested from 6 typical strains of T rubrum and used to inoculate wells of microtiter plates. These wells were also filled with a γ-cyclodextrin curcuminoid formulation with 0.1% DMSO and Sabouraud broth. The assays were then irradiated with visible light (wavelength 420 nm, 45 J/cm² ). After 24 hours, curcuminoid was added once more, and irradiation was repeated. Fungal growth was monitored photometrically for 8 days and compared with controls.

RESULTS

Growth of all 6 T rubrum strains was completely inhibited by the photochemical treatment with the γ-cyclodextrin formulation of curcuminoids. The same curcuminoid formulation applied without irradiation had only a minor inhibitory effect.

DISCUSSION

Photo-inactivation of dermatophytes with a γ-cyclodextrin formulation of curcuminoids plus visible light is a very promising procedure with potential for a new treatment of patients with superficial tinea.

Anti-infective Properties of the Golden Spice Curcumin

The search for novel anti-infectives is one of the most important challenges in natural product research, as diseases caused by bacteria, viruses, and fungi are influencing the human society all over the world. Natural compounds are a continuing source of novel anti-infectives. Accordingly, curcumin, has been used for centuries in Asian traditional medicine to treat various disorders. Numerous studies have shown that curcumin possesses a wide spectrum of biological and pharmacological properties, acting, for example, as anti-inflammatory, anti-angiogenic and anti-neoplastic, while no toxicity is associated with the compound. Recently, curcumin’s antiviral and antibacterial activity was investigated, and it was shown to act against various important human pathogens like the influenza virus, hepatitis C virus, HIV and strains of Staphylococcus, Streptococcus, and Pseudomonas. Despite the potency, curcumin has not yet been approved as a therapeutic antiviral agent. This review summarizes the current knowledge and future perspectives of the antiviral, antibacterial, and antifungal effects of curcumin.