Photophysics, photochemistry and photobiology of curcumin: Studies from organic solutions, bio-mimetics and living cells

Co-encapsulation of curcumin and fucoxanthin in solid-in-oil-in-water multilayer emulsions: Characterization, stability and programmed sequential release

To enhance the bioavailability of bioactives with varying efficacy in the gastrointestinal tract (GIT), a co-delivery system of solid-in-oil-in-water (S/O/W) emulsion was designed for the co-encapsulation of two bioactives in this paper. S/O/W emulsions were fabricated utilizing fucoxanthin (FUC)-loaded nanoparticles (NPs) as the solid phase, coconut oil containing curcumin (Cur) as the oil phase, and carboxymethyl starch (CMS)/propylene glycol alginate (PGA) complex as the aqueous phase. The high entrapment efficiency of Cur (82.3-91.3%) and FUC (96.0-96.1%) was found in the CMS/PGA complex-stabilized S/O/W emulsions. Encapsulation of Cur and FUC within S/O/W emulsions enhanced their UV and thermal stabilities. In addition, S/O/W emulsions prepared with CMS/PGA complexes displayed good stability. More importantly, the formed S/O/W emulsion possessed programmed sequential release characteristics, delivering Cur and FUC to the small intestine and colon, respectively. These results contributed to designing co-delivery systems for the programmed sequential release of two hydrophobic nutrients in the GIT.

Increasing the bioavailability of curcumin using a green supercritical fluid technology-assisted approach based on simultaneous starch aerogel formation-curcumin impregnation

A green approach based on simultaneous starch aerogel formation-curcumin impregnation via supercritical fluid technology was used to increase the bioavailability of curcumin. The loading amounts of curcumin were 16.4, 21.4, and 24.9 mg/g of aerogel for the 25% Amyl-loaded, 55% Amyl-loaded, and 72% Amyl-loaded samples, respectively. Curcumin-loaded aerogels showed the eventual distribution of curcumin in the hydrophobic area of the internal structure of the aerogels. In vitro gastrointestinal release profiles demonstrated the enhanced curcumin release from the curcumin-loaded aerogel formulations produced by the SC-CO2 technology over free curcumin. After intestinal digestion, the percentage of released curcumin from 25% Amyl-loaded, 55% Amyl-loaded, and 72% Amyl-loaded was 7.2, 12.1, and 12.1%, respectively, while the release of native curcumin was only 0.5%. Caco-2 cell permeation studies revealed superior bioavailability of curcumin from the curcumin-loaded aerogels. Curcumin-loaded aerogels exhibited improved storage stability than free curcumin.

Photodynamic therapy with curcumin and near-infrared radiation as an antitumor strategy to glioblastoma cells

Glioblastoma is a malignant neoplasm that develops in the central nervous system and is characterized by high rates of cell proliferation and invasion, presenting resistance to treatments and a poor prognosis. Photodynamic therapy (PDT) is a therapeutic modality that can be applied in oncological cases and stands out for being less invasive. Photosensitizers (PS) of natural origin gained prominence in PDT. Curcumin (CUR) is a natural compound that has been used in PDT, considered a promising PS. In this work, we evaluated the effects of PDT-mediated CUR and near-infrared radiation (NIR) in glioblastoma cells. Through trypan blue exclusion analysis, we chose the concentration of 5 μM of CUR and the dose of 2 J/cm2 of NIR that showed better responses in reducing the viable cell number in the C6 cell line and did not show cytotoxic/cytostatic effects in the HaCat cell line. Our results show that there is a positive interaction between CUR and NIR as a PDT model since there was an increase in ROS levels, a decrease in cell proliferation, increase in cytotoxicity with cell death by autophagy and necrosis, in addition to the presence of oxidative damage to proteins. These results suggest that the use of CUR and NIR is a promising strategy for the antitumor application of PDT.

A crystal engineering approach for rational design of curcumin crystals for Pickering stabilization of emulsions

Emulsions stabilized via Pickering particles are becoming more and more popular due to their high stability and biocompatibility. Hence, developing new ways to produce effective Pickering particles is essential. In this work, we present a crystal engineering approach to obtain precise control over particle properties such as size, shape, and crystal structure, which may affect wettability and surface chemistry. A highly reproducible synthesis method via anti-solvent crystallization was developed to produce sub-micron sized curcumin crystals of the metastable form III, to be used as Pickering stabilizers. The produced crystals presented a clear hydrophobic nature, which was demonstrated by their preference to stabilize water-in-oil (W/O) emulsions. A comprehensive experimental and computational characterization of curcumin crystals was performed to rationalize their hydrophobic nature. Analytical techniques including Raman spectroscopy, powder X-ray diffraction (PXRD), Solid-State Nuclear Magnetic Resonance (SSNMR), scanning electron microscopy (SEM), Differential Scanning Calorimetry (DSC), confocal fluorescence microscopy and contact angle measurements were used to characterize curcumin particles in terms of shape, size and interfacial activity. The attachment energy model was instead applied to study relevant surface features of curcumin crystals, such as topology and facet-specific surface chemistry. This work contributes to the understanding of the effect of crystal properties on the mechanism of Pickering stabilization, and paves the way for the formulation of innovative products in fields ranging from pharmaceuticals to food science.

Synthesis of fluorinated curcumin derivatives for detecting amyloid plaques by 19F-MRI

The most prominent pathophysiological hallmark of Alzheimer's disease is the aggregation of amyloid-β (Aβ) peptides into senile plaques. Curcumin and its derivatives exhibit a high affinity for binding to Aβ fibrils, effectively inhibiting their growth. This property holds promise for both therapeutic applications and diagnostic molecular imaging. In this study, curcumin was functionalized with perfluoro-tert-butyl groups to create candidate molecular probes specifically targeted to Aβ fibrils for use in 19F-magnetic resonance imaging. Two types of fluorinated derivatives were considered: mono-substituted (containing nine fluorine atoms per molecule) and disubstituted (containing eighteen fluorine atoms). The linker connecting the perfluoro moiety with the curcumin scaffold was evaluated for its impact on binding affinity and water solubility. All mono-substituted compounds and one disubstituted compound exhibited a binding affinity toward Aβ fibrils on the same order of magnitude as reference curcumin. The insertion of a charged carboxylate group into the linker enhanced the water solubility of the probes. Compound Curc-Glu-F9 (with one L-glutamyl moiety and a perfluoro-tert-butyl group), showed the best properties in terms of binding affinity towards Aβ fibrils, water solubility, and intensity of the 19F-NMR signal in the Aβ oligomer bound form.

The Bright Side of Curcumin: A Narrative Review of Its Therapeutic Potential in Cancer Management

Curcumin, a polyphenolic compound derived from Curcuma longa, exhibits significant therapeutic potential in cancer management. This review explores curcumin's mechanisms of action, the challenges related to its bioavailability, and its enhancement through modern technology and approaches. Curcumin demonstrates strong antioxidant and anti-inflammatory properties, contributing to its ability to neutralize free radicals and inhibit inflammatory mediators. Its anticancer effects are mediated by inducing apoptosis, inhibiting cell proliferation, and interfering with tumor growth pathways in various colon, pancreatic, and breast cancers. However, its clinical application is limited by its poor bioavailability due to its rapid metabolism and low absorption. Novel delivery systems, such as curcumin-loaded hydrogels and nanoparticles, have shown promise in improving curcumin bioavailability and therapeutic efficacy. Additionally, photodynamic therapy has emerged as a complementary approach, where light exposure enhances curcumin's anticancer effects by modulating molecular pathways crucial for tumor cell growth and survival. Studies highlight that combining low concentrations of curcumin with visible light irradiation significantly boosts its antitumor efficacy compared to curcumin alone. The interaction of curcumin with cytochromes or drug transporters may play a crucial role in altering the pharmacokinetics of conventional medications, which necessitates careful consideration in clinical settings. Future research should focus on optimizing delivery mechanisms and understanding curcumin's pharmacokinetics to fully harness its therapeutic potential in cancer treatment.

Curcumin's membrane localization and disruptive effects on cellular processes - insights from neuroblastoma, leukemic cells, and Langmuir monolayers

In therapies, curcumin is now commonly formulated in liposomal form, administered through injections or creams. This enhances its concentration at the cellular level compared to its natural form ingestion. Due to its hydrophobic nature, curcumin is situated in the lipid part of the membrane, thereby modifying its properties and influencing processes The aim of the research was to investigate whether the toxicity of specific concentrations of curcumin, assessed through biochemical tests for the SK-N-SH and H-60 cell lines, is related to structural changes in the membranes of these cells, caused by the localization of curcumin in their hydrophobic regions. Biochemical tests were performed using spectrophotometric methods. Langmuir technique were used to evaluate the interaction of the curcumin with the studied lipids. Direct introduction of curcumin into the membranes alters their physicochemical parameters. The extent of these changes depends on the initial properties of the membrane. In the conducted research, it has been demonstrated that curcumin may exhibit toxicity to human cells. The mechanism of this toxicity is related to its localization in cell membranes, leading to their dysfunction. The sensitivity of cells to curcumin presence depends on the saturation level of their membranes; the more rigid the membrane, the lower the concentration of curcumin causes its disruption.

The Effects of Fisetin and Curcumin on Oxidative Damage Caused by Transition Metals in Neurodegenerative Diseases

Neurodegenerative diseases pose a significant health challenge for the elderly. The escalating presence of toxic metals and chemicals in the environment is a potential contributor to central nervous system dysfunction and the onset of neurodegenerative conditions. Transition metals play a crucial role in various pathophysiological mechanisms associated with prevalent neurodegenerative diseases such as Alzheimer's and Parkinson's. Given the ubiquitous exposure to metals from diverse sources in everyday life, the workplace, and the environment, most of the population faces regular contact with different forms of these metals. Disturbances in the levels and homeostasis of certain transition metals are closely linked to the manifestation of neurodegenerative disorders. Oxidative damage further exacerbates the progression of neurological consequences. Presently, there exists no curative therapy for individuals afflicted by neurodegenerative diseases, with treatment approaches primarily focusing on alleviating pathological symptoms. Within the realm of biologically active compounds derived from plants, flavonoids and curcuminoids stand out for their extensively documented antioxidant, antiplatelet, and neuroprotective properties. The utilization of these compounds holds the potential to formulate highly effective therapeutic strategies for managing neurodegenerative diseases. This review provides a comprehensive overview of the impact of abnormal metal levels, particularly copper, iron, and zinc, on the initiation and progression of neurodegenerative diseases. Additionally, it aims to elucidate the potential of fisetin and curcumin to inhibit or decelerate the neurodegenerative process.

ChemFH: an integrated tool for screening frequent false positives in chemical biology and drug discovery

High-throughput screening rapidly tests an extensive array of chemical compounds to identify hit compounds for specific biological targets in drug discovery. However, false-positive results disrupt hit compound screening, leading to wastage of time and resources. To address this, we propose ChemFH, an integrated online platform facilitating rapid virtual evaluation of potential false positives, including colloidal aggregators, spectroscopic interference compounds, firefly luciferase inhibitors, chemical reactive compounds, promiscuous compounds, and other assay interferences. By leveraging a dataset containing 823 391 compounds, we constructed high-quality prediction models using multi-task directed message-passing network (DMPNN) architectures combining uncertainty estimation, yielding an average AUC value of 0.91. Furthermore, ChemFH incorporated 1441 representative alert substructures derived from the collected data and ten commonly used frequent hitter screening rules. ChemFH was validated with an external set of 75 compounds. Subsequently, the virtual screening capability of ChemFH was successfully confirmed through its application to five virtual screening libraries. Furthermore, ChemFH underwent additional validation on two natural products and FDA-approved drugs, yielding reliable and accurate results. ChemFH is a comprehensive, reliable, and computationally efficient screening pipeline that facilitates the identification of true positive results in assays, contributing to enhanced efficiency and success rates in drug discovery. ChemFH is freely available via https://chemfh.scbdd.com/.

Exploring the World of Curcumin: Photophysics, Photochemistry, and Applications in Nanoscience and Biology

Curcumin is a bright yellow naturally occurring polyphenol which is the principal component of turmeric. It is used as herbal supplement, cosmetics ingredient, and food coloring agent. Over the years, the therapeutic properties of the natural product curcumin have gone unexploited but not unnoticed. Curcumin cannot be employed as a drug due to limitations such as low aqueous solubility and limited bioavailability. Many attempts have been made to overcome these limitations by confining the drug in various confined media to enhance its bioavailability. The biomolecule is emissive and undergoes fundamental excited state processes such as solvation dynamics and excited state intramolecular proton transfer (ESIPT). Curcumin based biomaterials and nanomaterials are also a fast advancing field where curcumin is an intrinsic component necessary for formation of these materials and no longer added as an external free drug. In this review, we will summarize the recent research on the photophysical and photochemical properties of curcumin and its excited state dynamics in various bio-mimicking systems. At the same time we wish to also incorporate the various applications of curcumin, especially in biology. Lastly due to the growing importance of materials science, we will briefly discuss some recent advances on curcumin based biomaterials and nanomaterials. We believe such a compilation of recent research surrounding curcumin will provide an overall understanding of its potentialities in different areas.

Engineered Robust Hydrophobic/Hydrophilic Nanofibrous Scaffolds with Drug-Eluting, Antioxidant, and Antimicrobial Capacity

Multifunctional nanofibrous architectures have attracted extensive attention for biomedical applications due to their adjustable and versatile properties. Electrospun fabrics stand out as key building blocks for these structures, yet improving their mechanobiological and physicochemical performance is a challenge. Here, we introduce biodegradable engineered hydrophobic/hydrophilic scaffolds consisting of electrospun polylactide nanofibers coated with drug-eluting synthetic (poly(vinyl alcohol)) and natural (starch) polymers. The microstructure of these composite scaffolds was tailored for an increased hydrophilicity, optimized permeability, water retention capacity of up to 5.1 g/g, and enhanced mechanical properties under both dry and wet conditions. Regarding the latter, normalized tensile strengths of up to 32.4 MPa were achieved thanks to the improved fiber interactions and fiber-coating stress transfer. Curcumin was employed as a model drug, and its sustained release in a pure aqueous medium was investigated for 35 days. An in-depth study of the release kinetics revealed the outstanding water solubility and bioavailability of curcumin, owing to its complexation with the hydrophilic polymers and further delineated the role of the hydrophobic nanofibrous network in regulating its release rate. The modified curcumin endowed the composites with antioxidant activities up to 5.7 times higher than that of free curcumin as well as promising anti-inflammatory and bacteriostatic activities. The cytocompatibility and cell proliferation capability on human dermal fibroblasts also evidenced the safe use of the constructs. Finally, the fabrics present pH-responsive color-changing behavior easily distinguishable within the pH range of 5-9. Thus, these designs offer a facile and cost-effective roadmap for the fabrication of smart multifunctional biomaterials, especially for chronic wound healing.

Enhancement of Solubility, Stability, Cellular Uptake, and Bioactivity of Curcumin by Polyvinyl Alcohol

The biological activities and related mechanisms of curcumin, a major polyphenolic compound in turmeric, the rhizome of Curcuma longa, have been extensively investigated. Due to its poor solubility in water, the analysis of curcumin's biological activities is limited in most aqueous experimental systems. In the present study, the effects of polyvinyl alcohol (PVA), a dietary-compatible vehicle, on the solubility, stability, cellular uptake, and bioactivities of curcumin were investigated. Curcumin solubility was improved significantly by PVA; the color intensity of curcumin aqueous solution in the presence of PVA increased concentration-dependently with its peak shift to a shorter wavelength. Improved suspension stability and photostability of curcumin in an aqueous solution were also observed in the presence of PVA, even at 62.5 μg/mL. The scavenging activities of curcumin against DPPH, ABTS, AAPH radicals, and nitric oxide were enhanced significantly in the presence of PVA. PVA at 250 μg/mL also significantly enhanced the cytotoxic activity of curcumin against both HCT 116 colon cancer and INT 407 (HeLa-derived) embryonic intestinal cells by reducing the IC50 from 16 to 11 μM and 25 to 15 μM, respectively. PVA improved the cellular uptake of curcumin in a concentration-dependent manner in INT 407 cells; it increased the cellular levels more effectively at lower curcumin treatment concentrations. The present results indicate that PVA improves the solubility and stability of curcumin, and changes in these chemical behaviors of curcumin in aqueous systems by PVA could enhance the bioavailability and pharmacological efficacy of curcumin.

Curcumin and its nano-formulations combined with exercise: From molecular mechanisms to clinic

Curcumin is a strong substance derived from turmeric, a popular spice, renowned for its antioxidant and anti-inflammatory abilities. The study delved deeply into a thorough examination of various sources to evaluate the impact of both regular curcumin and nano-formulated curcumin on elements that impact physical performance, including muscular strain, discomfort, swelling, and oxidative tension. While engaging in exercise, the body experiences a rise in reactive oxygen species and inflammation. As a result, it is important to ensure a proper balance between internal and external sources of antioxidants to maintain stability in the skeletal muscle. Without this balance, there is a risk of muscle soreness, damage, and ultimately, a decline in exercise performance. Curcumin possesses the ability to enhance physical performance and reduce the symptoms of muscle fatigue and injury by virtue of its antioxidative and anti-inflammatory properties. Including curcumin supplements appears to have advantageous effects on various aspects of exercise, such as enhancing performance, assisting with recovery, lessening muscle damage and discomfort, and lowering levels of inflammation and oxidative stress. However, a thorough assessment is necessary to precisely gauge the healing advantages of curcumin in enhancing exercise ability and reducing recovery time.

Longevity and anti-aging effects of curcumin supplementation

Aging is a gradual and irreversible process that is accompanied by an overall decline in cellular function and a significant increase in the risk of age-associated disorders. Generally, delaying aging is a more effective method than treating diseases associated with aging. Currently, researchers are focused on natural compounds and their therapeutic and health benefits. Curcumin is the main active substance that is present in turmeric, a spice that is made up of the roots and rhizomes of the Curcuma longa plant. Curcumin demonstrated a positive impact on slowing down the aging process by postponing age-related changes. This compound may have anti-aging properties by changing levels of proteins involved in the aging process, such as sirtuins and AMPK, and inhibiting pro-aging proteins, such as NF-κB and mTOR. In clinical research, this herbal compound has been extensively examined in terms of safety, efficacy, and pharmacokinetics. There are numerous effects of curcumin on mechanisms related to aging and human diseases, so we discuss many of them in detail in this review.

Time-resolved keto-enol tautomerization of the medicinal pigment curcumin

Curcumin is a medicinal agent that exhibits anti-cancer and anti-Alzheimer's disease properties. It has a keto-enol moiety that gives rise to many of its chemical properties including metal complexation and acid-base equilibria. A previous study has shown that keto-enol tautomerization at this moiety is implicated in the anti-Alzheimer's disease effect of curcumin, highlighting the importance of this process. In this study, tautomerization of curcumin in methanol, acetone and acetonitrile was investigated using time-resolved 1H nuclear magnetic resonance spectroscopy. Curcumin undergoes hydrogen-deuterium exchange with the solvents and the proton resonance peak corresponding to the hydrogen at the α-carbon position (Cα) decays as a function of time, signifying deuteration at this position. Because tautomerization is the rate limiting step in the deuteration of curcumin at the Cα position, the rate of tautomerization is inferred from the rate of deuteration. The rate constant of tautomerization of curcumin shows a temperature dependence and analysis using the Arrhenius equation revealed activation energies (Ea) of tautomerization of (80.1 ± 5.9), (64.1 ± 1.0) and (68.3 ± 5.5) kJ mol-1 in methanol, D2O/acetone and D2O/acetonitrile, respectively. Insight into the role of water in tautomerization of curcumin was further offered by density functional theory studies. The transition state of tautomerization was optimized in the presence of water molecules. The results show a hydrogen-bonded solvent bridge between the diketo moiety and Cα of curcumin. The Ea of tautomerization of curcumin shows a strong dependence on the number of water molecules in the solvent bridge, indicating the critical role played by the solvent bridge in catalyzing tautomerization of curcumin.

Ratiometric dual-emitting thermometers based on rhodamine B dye-incorporated (nano) curcumin periodic mesoporous organosilicas for bioapplications

This study explores the potential of combining periodic mesoporous organosilicas (PMOs) with a fluorescent dye to develop a ratiometric thermometry system with enhanced stability, sensitivity, and biocompatibility. PMOs, ordered porous materials known for their stability and versatility, serve as an ideal platform. Curcumin, a natural polyphenol and fluorescent dye, is incorporated into PMOs to develop curcumin-functionalized PMOs (C-PMO) and curcumin-pyrazole-functionalized PMOs (CP-PMO) via hydrolysis and co-condensation. These PMOs exhibit temperature-dependent fluorescence properties. The next step involves encapsulating rhodamine B (RhB) dye within the PMO pores to create dual-emitting PMO@dye nanocomposites, followed by a lipid bilayer (LB) coating to enhance biocompatibility and dye retention. Remarkably, within the physiological temperature range, C-PMO@RhB@LB and CP-PMO@RhB@LB demonstrate noteworthy maximum relative sensitivity (Sr) values of up to 1.69 and 2.60% K-1, respectively. This approach offers versatile means to create various ratiometric thermometers by incorporating different fluorescent dyes, holding promise for future temperature sensing applications.

Green and single-step simultaneous composite starch aerogel formation-high bioavailability curcumin particle formation

The high porosity and specific surface area of aerogels offer an ideal platform for loading bioactive molecules. In the present study, the microstructure of the bio-based starch aerogels was modulated by the incorporation of chitosan. The starch hydrogel precursors were prepared from high amylose corn starch in the presence of 0, 0.50, and 0.75 wt% chitosan. Afterward, a green single-step simultaneous aerogel formation-curcumin deposition method was applied to impregnate curcumin into the aerogels through supercritical carbon dioxide (SC-CO2) drying technology. Composite starch/chitosan aerogels showed a more open porous structure and lighter weight than the neat starch counterpart. Confocal microscopy and fluorescence spectroscopy analysis confirmed curcumin molecules' attachment to the aerogels' hydrophobic cavities. The impregnation capacity was 24-27 mg curcumin per gram of aerogel depending on the composition of the aerogels. The loading of curcumin in the aerogels significantly enhanced the bioaccessibility of curcumin in the simulated gastrointestinal fluid by almost 30-fold when compared to the unloaded curcumin. Furthermore, the bioaccessibility of the curcumin loaded in starch-chitosan composite aerogels was higher than that in neat starch aerogels. While unloaded curcumin showed an undetectable intestinal Caco-2 cell transportation, curcumin-loaded aerogels revealed a cumulative curcumin passing of 0.15-0.23 μg/mL.

Near infra-red absorbing Quinolizidine fused curcuminoid-BF2 chelate and its applications in photodynamic therapy using MCF-7 and A549 cells

Metal-free near-infrared absorbing photosensitizers (PS) have been considered promising candidates for photodynamic therapy. Curcumin, curcuminoid, and its derivatives have therapeutic values due to their anti-inflammatory, antifungal, and antiproliferative properties. Curcuminoid-BF2 chelates have also been studied as cell imaging probes, however, their applications in photodynamic therapy are rare. In this article, we describe the synthesis and therapeutic evaluation of quinolizidine fused curcuminoid-BF2 chelate (Quinolizidine CUR-BF2) containing an acid-sensitive group. This donor-acceptor-donor curcuminoid-BF2 derivative exhibits absorption and emission in the deep red region with an absorption band maximum of ∼647 nm and a weak emission band at approximately 713 nm. It is interesting to note that this derivative has a high molar extinction coefficient (164,655 M-1cm-1). Quinolizidine CUR-BF2 possesses intramolecular charge transfer properties, facilitating the production of singlet oxygen (1O2), which plays a crucial role in cell death. Additionally, Quinolizidine CUR-BF2 can enable the selective release of active ingredients in an acidic medium (pH 5). Furthermore, the nanoaggregates of PS were prepared by encapsulating Quinolizidine CUR-BF2 within Pluronic F127 block co-polymer for better water-dispersibility and enhanced cellular uptake. Dark cytotoxicity of nanoaggregates was found to be negligible, whereas they exhibited significant photoinduced cytotoxicity towards cancer cells (MCF-7 and A549) under irradiation of 635 nm light. Further, the cell death pathway using Quinolizidine CUR-BF2 nanoaggregates as PS is found to occur through apoptosis. Specifically, the present study deals with the successful preparation of Quinolizidine CUR-BF2 nanoaggregates for enhanced water-dispersibility and cellular uptake as well as the efficacy evaluation of developed nanoaggregates for photodynamic therapy.

Theoretical studies on the photo protective mechanism of curcuminoids

In this work, the deactivation pathways of curcuminoids after photoexcitation was studied by employing density functional theory to explore their UVA radiation screening capacity. A comprehensive computational characterization of the excited-state processes of curcumin, demethoxycurcumin, and bis-demethoxycurcumin was done. The molecules exist in diketo and enol forms which are in equilibrium and interconvertible through keto-enol tautomerism. The enolic forms of each of the studied molecules have eight geometric cis-trans isomers as a result of torsion rotation about three different carbon-carbon double bonds across the aliphatic chain. For each geometric isomer, sixteen possible rotamers are found to exist due to rotation about five different carbon-carbon single bond rotations, also across the skeleton of the aliphatic chain. Upon photoexcitation, the studied molecules follow three main pathways of radiationless decay: (a) rotamerism and interconversion between rotamers of comparable energies which are in equilibrium, (b) interconversion between the cis-trans geometrical isomers where an efficient vibrational relaxation path is formed at ∼90° during torsion rotation about carbon-carbon double bond, and (c) excited state intramolecular proton transfer in a single O-H stretching vibration through a cyclic intramolecular hydrogen bonded ring formed at the centre of the molecule giving back the original structure. The absorption and emission spectra of the molecules were also simulated where the theoretically obtained absorption and emission maxima are close to the reported experimental values.

Plant-Derived Polyphenols to Prevent and Treat Oral Mucositis Induced by Chemo- and Radiotherapy in Head and Neck Cancers Management

Oral Mucositis (OM) is the most common side effect due to chemotherapy and radiotherapy, which are the conventional treatment options for head and neck cancers. OM is a severe inflammatory condition characterized by multifactorial etiopathogenesis. It further negatively affects patients' quality of life by severe impairment of normal oral functions. Consequently, it is mandatory to identify new effective therapeutic approaches to both prevent and treat OM while also avoiding any recurrence. Polyphenols recently attracted the interest of the scientific community due to their low toxicity and wide range of biological activities making them ideal candidates for several applications in the odontostomatological field, particularly against OM. This review collects the in vivo studies and the clinical trials conducted over the past 13 years evaluating the preventive and curative effects of several polyphenolic compounds towards chemo- and radiotherapy-induced OM, both when administered alone or as a plant-extracted phytocomplex. The literature fully confirms the usefulness of these molecules, thus opening the possibility of their clinical application. However, polyphenol limitations (e.g., unfavourable physicochemical properties and susceptibility to degradation) have emerged. Consequently, the interest of the scientific community should be focused on developing innovative delivery systems able to stabilize polyphenols, thus facilitating topical administration and maximizing their efficacy.

Nonlinear Optical Properties and All Optical Switching of Curcumin Derivatives

In this work OR1(E1,6E) -1,7-bis (4-propyloxy phenyl) hepta-1,6-diene-3,5 dione compound is synthesized. The compound has been characterized via computational technique by studying the molecule's electronic structures through calculating its HOMO and LUMO energies, and its band gap energy (EHOMO-ELUMO). The nonlinear refractive index (NLRI) of the solution of OR1 compound in DMF solvent is determined using diffraction patterns (DPs) which resulted when a continuous wave laser beam of wavelength 473 nm traversed the compound solution in a glass cell of 1 mm thickness. By counting the number of rings under maximum beam input power, the NLRI of value 10- 6 cm2/W resulted. The NLRI is calculated once more via the Z-scan technique and a value of 0.25 × 10- 7 cm2/W is obtained. The vertical convection current in the OR1 compound solution appears to be responsible for the asymmetries noticed in the DPs. The temporal variation of each DP is noticed together with the evolution of DPs against beam input power. DPs are numerically simulated based on the Fresnel-Kirchhoff integral with good accord compared to the experimental findings. Dynamic and static all-optical switching in the OR1 compound using two laser beams (473 and 532 nm) is tested successfully.

Mechanism insights of curcumin and its analogues in cancer: An update

Cancer is the world's second leading cause of mortality and one of the major public health problems. Cancer incidence and mortality rates remain high despite the great advancements in existing therapeutic, diagnostic, and preventive approaches. Therefore, a quest for less toxic and more efficient anti-cancer strategies is still at the forefront of the current research. Traditionally important, curcumin commonly known as a wonder molecule has received considerable attention as an anti-cancer, anti-inflammatory, and antioxidant candidate. However, limited water solubility and low bioavailability restrict its extensive utility in different pathological states. The investigators are making consistent efforts to develop newer strategies to overcome its limitations by designing different analogues with better pharmacokinetic and pharmacodynamic properties. The present review highlights the recent updates on curcumin and its analogues with special emphasis on various mechanistic pathways involved in anti-cancer activity. In addition, the structure-activity relationship of curcumin analogues has also been precisely discussed. This article will also provide key information for the design and development of newer curcumin analogues with desired pharmacokinetic and pharmacodynamic profiles and will provide in depth understanding of molecular pathways involved in the anti-cancer activities.

Investigation of ultrafast carrier dynamics in curcumin dye for environment friendly dye-sensitized solar cell

Natural dyes have been widely employed in the fabrication of dye-sensitized solar cells (DSSCs). DSSCs are favored for their cost-effective, and simple fabrication process relies on metal-based and organic dyes. The choice of dyes greatly affects the performance of DSSCs. DSSCs have found a lot of applications in indoor, solar power gadgets with reasonable efficiency up to 13%. Nonetheless, despite advances in DSSC technology, the complex photophysics and excited state dynamics associated with natural dyes employed in DSSCs remain elusive and have not been adequately investigated. This information gap emphasizes the need for more study and analysis into the behavior of these dyes, since understanding their underlying principles might lead to major improvements in DSSC performance and efficiency. In this work, we have investigated the fundamental characteristics and excited-state carrier dynamics of natural dye curcumin using ultrafast transient absorption (TA) spectroscopy technique. The curcumin dye shows delay time-dependent positive and negative signals in the TA spectra, which are related to excited state absorption and stimulated emission. We also found that hydrogen bonding and polarity effect of solvent significantly influence the carrier dynamics of curcumin. Ultrafast lifetime component indicates that hydrogen-bond rearrangements are involved in the kinetics of the relaxation process of the S1 state of curcumin photo-sensitizer.

Current appraises of therapeutic applications of nanocurcumin: A novel drug delivery approach for biomaterials in dentistry

Curcumin is a natural herb and polyphenol that is obtained from the medicinal plant Curcuma longa. It's anti-bacterial, anti-inflammatory, anti-cancer, anti-mutagenic, antioxidant and antifungal properties can be leveraged to treat a myriad of oral and systemic diseases. However, natural curcumin has weak solubility, limited bioavailability and undergoes rapid degradation, which severely limits its therapeutic potential. To overcome these drawbacks, nanocurcumin (nCur) formulations have been developed for improved biomaterial delivery and enhanced treatment outcomes. This novel biomaterial holds tremendous promise for the treatment of various oral diseases, the majority of which are caused by dental biofilm. These include dental caries, periodontal disease, root canal infection and peri-implant diseases, as well as other non-biofilm mediated oral diseases such as oral cancer and oral lichen planus. A number of in-vitro studies have demonstrated the antibacterial efficacy of nCur in various formulations against common oral pathogens such as S. mutans, P. gingivalis and E. faecalis, which are strongly associated with dental caries, periodontitis and root canal infection, respectively. In addition, some clinical studies were suggestive of the notion that nCur can indeed enhance the clinical outcomes of oral diseases such as periodontitis and oral lichen planus, but the level of evidence was very low due to the small number of studies and the methodological limitations of the available studies. The versatility of nCur to treat a diverse range of oral diseases augurs well for its future in dentistry, as reflected by rapid pace in which studies pertaining to this topic are published in the scientific literature. In order to keep abreast of the latest development of nCur in dentistry, this narrative review was undertaken. The aim of this narrative review is to provide a contemporaneous update of the chemistry, properties, mechanism of action, and scientific evidence behind the usage of nCur in dentistry.

A Systematic Evaluation of Curcumin Concentrations and Blue Light Parameters towards Antimicrobial Photodynamic Therapy against Cariogenic Microorganisms

Dental caries is a highly preventable and costly disease. Unfortunately, the current management strategies are inadequate at reducing the incidence and new minimally invasive strategies are needed. In this study, a systematic evaluation of specific light parameters and aqueous curcumin concentrations for antimicrobial photodynamic therapy (aPDT) was conducted. Aqueous solutions of curcumin were first prepared and evaluated for their light absorbance after applying different ~56 mW/cm2 blue light treatments in a continuous application mode. Next, these same light treatments as well as different application modes were applied to the curcumin solutions and the molar absorptivity coefficient, reactive oxygen species (ROS) release, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) for Streptococcus mutans and the MIC and minimum fungicidal concentration (MFC) for Candida albicans were measured. After up to 1 min of light treatment, the molar absorptivity of curcumin when added to culture media was lower than that for water only; however, at higher energy levels, this difference was not apparent. There was a noted dependence on both ROS type and cariogenic microorganism species on the sensitivity to both blue light treatment and application mode. In conclusion, this study provides new information towards improving the agonistic potential of aPDT associated with curcumin against cariogenic microorganisms.

Eco-Friendly Multilayer Coating Harnessing the Functional Features of Curcuma-Based Pigment and Rice Bran Wax as a Hydrophobic Filler

This work aims to highlight the multiple features shown by curcuma-based pigment and rice bran wax, which can be selectively employed as bio-based additives for the realization of multilayer wood coatings with multiple functionalities, harnessing the capabilities of the two environmentally friendly fillers, in line with current environmental sustainability trends. The role of the two green materials on the morphology of the composite layers was examined through observations employing scanning electron and optical microscopy, revealing a strong alteration of the film's appearance, both its color and reflectivity. Additionally, their influence on the paint's resilience was assessed by exposing the samples to UV-B radiation and consecutive thermal shocks. The coating displayed a clear and uniform change in color because of substantial curcuma powder photo-degradation but it remained exceptionally stable when subjected to thermal stresses. Moreover, the protective properties of the coatings were evaluated by conducting liquid resistance tests and water uptake tests, while the hardness and the abrasion resistance of the coatings were assessed to evaluate the effect of the additives on the mechanical properties of the coatings. In conclusion, this study showcases the promising joint action of curcuma-based pigment and rice bran wax in multilayer coatings. This combination offers vibrant yellow tones and an appealing appearance to the paint, enhances the surface's water-repellent properties, and improves the mechanical resistance of the coatings.

Curcumin Analogue Spectral, Nonlinear Optical Properties and All-optical Switching Using Visible, Low Power Cw Laser Beams

In this study, we conducted the synthesis and diagnosis of compound denoted as 1A3, specifically, (2E,4E,9E,11E)-7-chloro-2,12-diphenyltrideca-2,4,9,11-tetraene-6,8-dione. The photoluminescent and UV-vis spectral properties of this compound are investigated. The compound is dissolved in both chloroform and DMF for analysis purposes. Compound 1A3's nonlinear optical (NLO) characteristics when dissolved in DMF, are extensively studied through a series of experiments including diffraction patterns (DPs) and Z-scan. The optical limiting (OL) property of the 1A3 compound is tested and a threshold value of 12.4 mW at the wavelength 473 nm is obtained. Additionally, we explored its potential for all-optical switching utilizing two low-power visible laser beams. Notably, we achieved a significant nonlinear refractive index (NLRI) reaching up to 5.921 x 10-11 m2/W. To analyze the obtained diffraction patterns, we employed the Fresnel-Kirchhoff integral equation and conducted meticulous simulations. The numerical outcomes showed satisfactory agreement with the experimental observations.

A Photoreactor-Interfaced Mass Spectrometer: An Online Platform to Monitor Photochemical Reactions

An experimental platform is reported that allows for the online characterization of photochemical reactions by coupling a continuous flow photoreactor, equipped with LED light irradiation and a dual-tipped ESI source, directly to a mass spectrometer with electrospray ionization. The capabilities of this platform are demonstrated with two classes of photoreactions: (1) the photopolymerization of methyl methacrylate and (2) photocatalyzed alkyne insertion into a 1,2,3-benzotriazinone. The online technique provides rapid information to inform the underlying photochemical mechanism and evaluate the overall photochemistry.

Effect of pulsed light on curcumin chemical stability and antioxidant capacity

Curcumin is the major bioactive component in turmeric with potent antioxidant activity. Little is known about how pulsed light (PL) technology (an emerging non-thermal food processing technology relying on high intensity short duration flashes of light) can affect the chemical stability and antioxidant capacity of curcumin. This study found that PL treatment of fluence levels from 0 to 12.75 J/cm2 produced a fluence-dependent reduction in curcumin content. These results paralleled the production of a tentative curcumin dimer, identified as a potential photochemical transformation product. PL-treated curcumin at relatively higher fluence levels decreased chemical-based ORAC and ABTS antioxidant capacity, relative to control (P < 0.05). This contrasted the effect observed to increase coincidently both intracellular antioxidant capacity (e.g., DCFH-DA (P < 0.05)) and GSH/GSSG ratio (P < 0.05), respectively, in cultured differentiated Caco-2 cells. In conclusion, the application of PL on curcumin results in photochemical transformation reactions, such as dimerization, which in turn, can enhance biological antioxidant capacity in differentiated Caco-2 cells.

Natural photosensitizers potentiate the targeted antimicrobial photodynamic therapy as the Monkeypox virus entry inhibitors: An in silico approach

BACKGROUND

Monkeypox is a viral zoonotic disease that has emerged as a threat to public health. Currently, there is no treatment approved specifically targeting Monkeypox disease. Hence, it is essential to identify and develop therapeutic approaches to the Monkeypox virus. In the current in silico paper, we comprehensively involve using computer simulations and modeling to insights and predict hypotheses on the potential of natural photosensitizers-mediated targeted antimicrobial photodynamic therapy (aPDT) against D8L as a Monkeypox virus protein involved in viral cell entry.

MATERIALS AND METHODS

In the current study, computational techniques such as molecular docking were combined with in silico ADMET predictions to examine how Curcumin (Cur), Quercetin (Qct), and Riboflavin (Rib) as the natural photosensitizers bind to the D8L protein in Monkeypox virus, as well as to determine pharmacokinetic properties of these photosensitizers.

RESULTS

The three-dimensional structure of the D8L protein in the Monkeypox virus was constructed using homology modeling (PDB ID: 4E9O). According to the physicochemical properties and functional characterization, 4E9O was a stable protein with the nature of a hydrophilic structure. The docking studies employing a three-dimensional model of 4E9O with natural photosensitizers exhibited good binding affinity. D8L protein illustrated the best docking score (-7.6 kcal/mol) in relation to the Rib and displayed good docking scores in relation to the Cur (-7.0 kcal/mol) and Qct (-7.5 kcal/mol).

CONCLUSIONS

The findings revealed that all three photosensitizers were found to obey the criteria of Lipinski's rule of five and displayed drug-likeness. Moreover, all the tested photosensitizers were found to be non-hepatotoxic and non-cytotoxic. In summary, our investigation identified Cur, Qct, and Rib could efficiently interact with D8L protein with a strong binding affinity. It can be concluded that aPDT using these natural photosensitizers may be considered an adjuvant treatment against Monkeypox disease.

ESIPT-induced spin-orbit coupling enhancement leads to tautomer fluorescence quenching of the 10-HHBF molecule

We present novel insights into the interplay between excited state intramolecular proton transfer (ESIPT) and spin-orbit coupling (SOC) in the 10-hydroxy-11H-benzo[b]fluoren-11-one (10-HHBF) molecule, utilizing the time-dependent density functional theory approach and femtosecond transient absorption spectroscopy. Our discoveries entail a reassessment of the luminescence mechanism for 10-HHBF, characterizing it as an ESIPT fluorophore. Additionally, we demonstrate that the molecule undergoes intersystem crossing (ISC) following proton transfer, which quenches the fluorescence of the proton-transferred state, thus resulting in the absence of dual emission and a limited spectral range of fluorescence. Furthermore, our investigation reveals that 10-HHBF displays an SOC enhancement feature induced by ESIPT, which facilitates the ISC process. This trait serves as a barrier to the application of 10-HHBF in single-molecule white light emitters (SMWLEs). Our findings underscore the notable influence of the ESIPT-induced spin-orbit interaction enhancement on luminescent properties, which necessitates consideration in the design of SMWLEs.

Excited State Photophysics of Curcumin and its Modulation in Alkaline Non-Aqueous Medium

Curcumin, a well-known medicinal pigment, has seen limited applications in biology despite having great potential as a therapeutic drug. Deprotonation is one of the possible ways to enhance solubility of curcumin in polar solvent. Here, we have explored the effect of deprotonation on the ultrafast dynamics of this biomolecule with the help of the time-resolved fluorescence spectroscopic measurements using the femtosecond fluorescence upconversion technique. The excited state photophysics of fully deprotonated curcumin significantly differs from that of neutral curcumin. We have observed that the completely deprotonated curcumin not only has higher quantum yield, but also higher excited state lifetime and slower solvation dynamics in comparison to neutral curcumin. We propose solvation dynamics and intramolecular charge transfer as the excited state processes associated with the radiative decay of the completely deprotonated molecule, while ruling out the possibility of excited state proton exchange or proton transfer. Our results are well supported by time-dependent density-functional theory calculations. Lastly, we have also demonstrated the possibility of modulating the ultrafast dynamics of fully deprotonated curcumin using non-aqueous alkaline binary solvent mixtures. We believe our results will provide significant physical insight towards unveiling the excited state dynamics of this molecule.

Nonionizing Electromagnetic Irradiations; Biological Interactions, Human Safety

Human is usually exposed to environmental radiation from natural and man-made sources. Therefore, it is important to investigate the effects of exposure to environmental radiation, partly related to understanding and protecting against the risk of exposure to environmental radiation with beneficial and adverse impacts on human life. The rapid development of technologies causes a dramatic enhancement of radiation in the human environment. In this study, we address the biological effects caused by different fractions of non-ionizing electromagnetic irradiation to humans and describe possible approaches for minimizing adverse health effects initiated by radiation. The main focus was on biological mechanisms initiated by irradiation and represented protection, and safety approaches to prevent health disorders.

Curcumin-loaded mesoporous silica nanoparticles for drug delivery: synthesis, biological assays and therapeutic potential - a review

Curcumin-loaded mesoporous silica nanoparticles (MSNs) have shown promise as drug delivery systems to address the limited pharmacokinetic characteristics of curcumin. Functionalization with folic acid and PEGylation enhance anticancer activity, biocompatibility, stability, and permeability. Co-delivery with other drugs results in synergistically enhanced cytotoxic activity. Environment-responsive MSNs prevent undesirable drug leakage and increase selectivity towards target tissues. This review summarizes the methods of Cur-loaded MSN synthesis and functionalization and their application in various diseases, and also highlights the potential of Cur-loaded MSNs as a promising drug delivery system.

On the photobehaviour of curcumin in biocompatible hosts: The role of H-abstraction in the photodegradation and photosensitization

Curcumin (CUR) is a naturally occurring pigment extensively studied due to its therapeutic activity and delivered by suitable nanocarriers to overcome poor solubility in aqueous media. The significant absorption of CUR in the visible blue region has prompted its use as a potential phototherapeutic agent in treating infectious and cancer diseases, although the mechanism underlying the phototoxic effects is still not fully understood. This contribution investigates the photobehaviour of CUR within polymeric micelles, microemulsions, and zein nanoparticles, chosen as biocompatible nanocarriers, and human serum albumin as a representative biomolecule. Spectroscopic studies indicate that in all host systems, the enolic tautomeric form of CUR is converted in a significant amount of the diketo form because of the perturbation of the intramolecular hydrogen bond. This leads to intermolecular H-abstraction from the host components by the lowest excited triplet state of CUR with the formation of the corresponding ketyl radical, detected by nanosecond laser flash photolysis. This radical is oxidized by molecular oxygen, likely generating peroxyl and hydroperoxyl radical species, unless in Zein, reasonably due to the poor availability of oxygen in the closely packed structure of this nanocarrier. In contrast, no detectable formation of singlet oxygen was revealed in all the systems. Overall these results highlight the key role of the H-abstraction process over singlet oxygen sensitization as a primary photochemical pathway strictly dictated by the specific features of the microenvironment, providing new insights into the photoreactivity of CUR in biocompatible hosts that can also be useful for a better understanding of its phototoxicity mechanism.

Shining a Light on Prostate Cancer: Photodynamic Therapy and Combination Approaches

Prostate cancer is a major health concern worldwide, and current treatments, such as surgery, radiation therapy, and chemotherapy, are associated with significant side effects and limitations. Photodynamic therapy (PDT) is a promising alternative that has the potential to provide a minimally invasive and highly targeted approach to treating prostate cancer. PDT involves the use of photosensitizers (PSs) that are activated by light to produce reactive oxygen species (ROS), which can induce tumor cell death. There are two main types of PSs: synthetic and natural. Synthetic PSs are classified into four generations based on their structural and photophysical properties, while natural PSs are derived from plant and bacterial sources. Combining PDT with other therapies, such as photothermal therapy (PTT), photoimmunotherapy (PIT), and chemotherapy (CT), is also being explored as a way to improve its efficacy. This review provides an overview of conventional treatments for prostate cancer, the underlying principles of PDT, and the different types of PSs used in PDT as well as ongoing clinical studies. It also discusses the various forms of combination therapy being explored in the context of PDT for prostate cancer, as well as the challenges and opportunities associated with this approach. Overall, PDT has the potential to provide a more effective and less invasive treatment option for prostate cancer, and ongoing research is aimed at improving its selectivity and efficacy in clinical settings.

Novel Hydrogenated Derivatives of Chemically Modified Curcumin CMC2.24 Are Potent Inhibitors of Melanogenesis in an In Vitro Model: Influence of Degree of Hydrogenation

Chemically modified curcumin, CMC2.24, is a promising therapeutic that has shown efficacy in ameliorating excessive pigmentation in our previous studies. However, its inherent disadvantages of color, stability, solubility, and cytotoxicity to melanocytes and keratinocytes at concentrations > 4 µg/mL posed challenges in its use in cosmetic formulations. To overcome these limitations, chemical reduction by hydrogenation of CMC2.24 (compound 1) was developed to yield products at different time points of hydrogenation (1 h, 2 h, 4 h, and 24 h) referred to as partially (2, 3, 4) or fully hydrogenated (5) products, and the effects of the degree of hydrogenation on melanogenesis in vitro were explored. Compound 1 and products 2-5 were evaluated using mushroom tyrosinase activity assays with two substrates (L-tyrosine and L-DOPA), then cellular assays using B16F10 mouse melanoma cells, MNT-1 human melanoma cells, and physiological normal human melanocytes (HEMn-DP cells). The cytotoxicity, melanin contents, cellular tyrosinase activities, and cellular oxidative stress were evaluated. Moreover, the recovery of melanin contents in HEMn-DP cells was also studied. Our results provide novel insights into the role of the degree of hydrogenation of compound 1 on the biological effects of melanogenesis, which were dependent on cell type. To the best of our knowledge, this is the first study to show that in HEMn-DP cells, the anti-melanogenic efficacy of the yellow-colored CMC2.24 is retained as early as 1 h after its hydrogenation; this efficacy is enhanced with longer durations of hydrogenation, with a robust efficacy achieved for the 24 h hydrogenated product 5 at the lowest concentration of 4 µg/mL. A similar potency could be achieved for product 4 at higher concentrations, although interestingly, both differ only by a minor amount of dihydro-CMC2.24. Our results indicate promise for using products 4 & 5 as a skin-lightener in cosmetic formulations with the advantages of lack of color combined with a potency much greater than that of the parent compound 1 at lower concentrations and reversibility of the effects on melanocytes. This, along with the easy synthesis and scale-up of the hydrogenation method for CMC2.24 and the documented higher solubility, stability, and bioavailability of tetrahydrocurcumin, provides further impetus to incorporating these derivatives in cosmetic formulations. The results of this study can help to extend the therapeutic window of the lead compound CMC2.24 by providing options for selecting partially or fully hydrogenated derivatives for cosmetic applications where a trade-off between color and efficacy is needed. Thus, the degree of hydrogenation can be tuned for desired biological effects. Further studies are warranted to evaluate the efficacy of products 4 & 5 at suppressing pigmentation in 3D skin-tissue equivalents and in vivo models.

Electrospinning in personal protective equipment for healthcare work

Protection in many service areas is mandatory for good performance in daily activities of workers, especially health areas. Personal protective equipment (PPE) is used to protect patients and health workers from contamination by harmful pathogens and body fluids during clinical attendance. The pandemic scenario caused by SARS-CoV-2 has shown that the world is not prepared to face global disease outbreaks, especially when it comes to the PPE of healthcare workers. In the last years, the world has faced a deficiency in the development of advanced technologies to produce high-quality PPE to attend to the exponential increasing demand. Electrospinning is a technology that can be used to produce high-quality PPE by improving the protective action of clothing. In the face of this concern, this manuscript presents as focus the potential of electrospinning to be applied in protective clothing. PPE mostly used by healthcare workers are also presented. The physico-chemical characteristics and production processes of medical textiles for PPE are addressed. Furthermore, an overview of the electrospinning technique is shown. It is important to highlight most research about electrospinning applied to PPE for health areas presents gaps and challenges; thus, future projections are also addressed in this manuscript.

Biocompatible anti-aging face mask prepared with curcumin and natural rubber with antioxidant properties

Natural rubber latex (NRL) is a biopolymer widely used in biomedical applications. In this work, we propose an innovative cosmetic face mask, combining the NRL's biological properties with curcumin (CURC), which has a high level of antioxidant activity (AA) to provide anti-aging benefits. Chemical, mechanical and morphological characterizations were performed. The CURC released by the NRL was evaluated by permeation in Franz cells. Cytotoxicity and hemolytic activity assays were performed to assess safety. The findings showed that the biological properties of CURC were preserved after loading in the NRL. About 44.2 % of CURC was released within the first six hours, and in vitro permeation showed that 9.36 % ± 0.65 was permeated over 24h. CURC-NRL was associated with a metabolic activity higher than 70 % in 3 T3 fibroblasts, cell viability ≥95 % in human dermal fibroblasts, and a hemolytic rate ≤ 2.24 % after 24 h. Furthermore, CURC-NRL maintained the mechanical characteristics (range suitable) for human skin application. We observed that CURC-NRL preserved ~20 % antioxidant activity from curcumin-free after loading in the NRL. Our results suggest that CURC-NRL has the potential to be used in the cosmetics industry, and the experimental methodology utilized in this study can be applied to different kinds of face masks.

Efficacy of methylene blue and curcumin mediated antimicrobial photodynamic therapy in the treatment of indirect pulp capping in permanent molar teeth

PURPOSE

This study aimed to evaluate the adhesive bond strength and antibacterial efficacy of methylene blue (MB)-mediated antimicrobial photodynamic therapy (aPDT) and curcumin (CUR)-mediated aPDT versus the conventional disinfectants, such as chlorhexidine gluconate (CHX) gel and sodium hypochlorite (NaOCl), for indirect pulp capping (IPC) treatment of permanent molars.

METHODS

One Hundred grossly carious human permanent molars were collected through non-traumatic extraction. All specimens were embedded in polyvinyl cross-sections to the cemento-enamel junction. The cavity preparation was conducted by grinding the samples using silicon carbide discs. After culturing Streptococcus mutans (S. mutans), a 10 µL of S. mutans suspension (10⁶ colony forming units/mL) was transferred in each tooth cavity and anaerobically incubated for 48 hours at 37°C. All specimens were randomly divided into 5 groups: Group-I: samples treated IPC; Group-II: samples treated with 2% CHX gel; Group-III: samples treated with 6% NaOCl; Group-IV: irradiation of prepared cavity with MB-mediated aPDT; and Group-V: irradiation of prepared cavity with CUR-mediated aPDT. After disinfection methods, the universal adhesive was used, and all specimens were restored using giomer. Eventually, confocal laser scanning microscopy, shear bond strength (SBS), micro-tensile bond strength (μTBS), four-point bending strength (4P-BS) analyses were performed, and the data were analyzed statistically.

RESULTS

At baseline, the highest SBS (48.8 ± 6.5 MPa), μTBS (54.3 ± 3.9 MPa), and 4P-BS (123 ± 32 MPa) scores were demonstrated by the samples treated with MB-mediated aPDT. However, after 12 months of storage, the highest SBS (42.3 ± 3.9 MPa) and μTBS (45.2 ± 6.6 MPa) scores were shown by samples treated with MB-mediated aPDT, while CUR-mediated aPDT treated samples demonstrated the highest 4P-BS scores (70 ± 18 MPa). Moreover, the highest antibacterial activity against S. mutans was shown by the samples treated with MB-mediated aPDT.

CONCLUSIONS

The application of aPDT, especially MB-mediated, demonstrated superior SBS, μTBS, and 4P-BS values as well as antibacterial activity against S. mutans as compared to 2% CHX gel and 6% NaOCl as cavity disinfectants for IPC treatment of permanent molars.

Curcumin-loaded alginate hydrogels for cancer therapy and wound healing applications: A review

Hydrogels have emerged as a versatile platform for a numerous biomedical application due to their ability to absorb a huge quantity of biofluids. In order to design hydrogels, natural polymers are an attractive option owing to their biocompatibility and biodegradability. Due to abundance in occurrence, cost effectiveness, and facile crosslinking approaches, alginate has been extensively investigated to fabricate hydrogel matrix. Management of cancer and chronic wounds have always been a challenge for pharmaceutical and healthcare sector. In both cases, curcumin have been shown significant improvement and effectiveness. However, the innate restraints like poor bioavailability, hydrophobicity, and rapid systemic clearance associated with curcumin have restricted its clinical translations. The current review explores the cascade of research around curcumin encapsulated alginate hydrogel matrix for wound healing and cancer therapy. The focus of the review is to emphasize the mechanistic effects of curcumin with its fate inside the cells. Further, the review discusses different approaches to designed curcumin loaded alginate hydrogels along with the parameters that regulates their release behavior. Finally, the review is concluded with emphasize on some key aspect on increasing the efficacy of these hydrogels along with novel strategies to further develop curcumin loaded alginate hydrogel matrix with multifacet applications.

Natural versus synthetic curcuminoids as photosensitizers: photobleaching and antimicrobial photodynamic therapy evaluation

Antimicrobial photodynamic therapy (aPDT) has been studied as an alternative to combat bacterial resistance to the commonly used antibiotics. aPDT requires the use of a photosensitizer and curcumin is one of the more promising, though the usage of natural curcumin can be inconsistent in certain biomedical uses due to differences in soil condition and turmeric age, besides a large quantity of the plant is necessary to obtain useful amounts of the actual molecule. As such, a synthetic analogue is preferred as it is pure, and its components are better characterized. The present work studied photophysical differences in both natural and synthetic curcumin using photobleaching experiments and searched for whether differences existed in aPDT studies against Staphylococcus aureus. The results showed a faster O₂ consumption and a singlet oxygen's generation rate lower by the synthetic curcumin, in comparison with the natural derivative. However, no statistical difference was observed when inactivating S. aureus and these results were following a concentration-based pattern. Thus, the use of synthetic curcumin is indicated, as it can be obtained in controlled amounts and with less environmental impact. Although there are small changes in a photophysical context comparing natural versus synthetic curcumins, we did not observe statistical differences in the photoinactivation of S.aureus bacteria, and reproducibility in biomedical contexts is better achieved with the synthetic analogue.

Curcumin-based molecular probes for fluorescence imaging of fungi

Fluorescence imaging is a powerful and widely used method to visualize and study living organisms. However, fungi are notoriously difficult to visualize using fluorescence microscopy, given that their cell wall represents a diffusion barrier, and the synthetic organic dyes available are very limited when compared to molecular probes available for other organisms. Moreover, these dyes are usually available in only one colour, preventing co-staining experiments. To fill this gap, curcumin-based molecular probes were designed based on the rationale that curcumin is fluorescent and has moderate toxicity toward fungi, implying its ability to cross the cell wall to reach targets in the intracellular compartments. A family of boron diketonate complexes was synthesized, based on a curcumin backbone, tuning their emission color from blue to red. These probes did not present noticeable toxicity to filamentous fungus and, when applied to their visualization, readily entered the cells and precisely localized in sub-cellular organelles, enabling their visualization.

Exploring Steroidal Surfactants as Potential Drug Carriers for an Anticancer Drug Curcumin: An Insight into the Effect of Surfactants' Structure on the Photophysical Properties, Stability, and Activity of Curcumin

Despite having tremendous medicinal benefits, the practical applications of curcumin are limited, owing to two major challenges: poor aqueous solubility and lack of bioavailability. In this regard, biosurfactant-based micellar systems have surged recently for the development of novel and more effective formulations because of their biological relevance. This study deals with a comprehensive and comparative investigation on the effect of seven structurally different steroidal surfactants on the photophysical properties of curcumin and also evaluates these steroidal surfactants as possible drug delivery media for curcumin. The photophysical properties of curcumin exhibited a strong dependence on the structure of the steroidal surfactant; the extent of excited-state proton transfer between curcumin and the surfactants depends strongly on the type of the side chain in the surfactants, which mostly dictates the photophysics of curcumin in the presence of these structural variants. The solubility of curcumin and its stability at different pHs and temperatures and in the presence of salt are significantly enhanced in the presence of these surfactants. Furthermore, the curcumin-loaded micelles exhibited improved intracellular uptake and cytotoxicity against MCF-7 cancer cells than pristine curcumin. Among these steroidal surfactants, CHAPS, the zwitterionic derivative of cholic acid, was the most efficient one to offer better solubility and stability to curcumin under all conditions, and the death rate of MCF-7 cells by curcumin was found to be the highest in the presence of CHAPS, indicating the enhanced bioavailability of curcumin. Therefore, CHAPS-based colloids are found to be promising candidates as potential drug carriers for curcumin.

Characterization of Stable Pyrazole Derivatives of Curcumin with Improved Cytotoxicity on Osteosarcoma Cell Lines

Curcumin (CUR) is a natural molecule that is unstable due to the presence of a bis-ketone. To obtain more stable derivatives in biological fluids, the bis-ketone was replaced with pyrazole or O-substituted oximes. Their stability in solution was studied by UV-visible spectrophotometry. The effects on proliferation were studied by MTT assay and/or clonogenicity assay. Induction of apoptosis was evaluated by annexin V staining and Western blot analysis. The bioavailability was obtained from the analysis of the molecular chemical-physical characteristics. The replacement of the bis-ketone with a pyrazole ring or O-substituted oximes improved the stability of all the CUR-derivative molecules. These derivatives were more stable than CUR in solution and were generally cytotoxic on a panel of cancer cell lines tested, and they promoted caspase-dependent apoptosis. Derivative 1 was the most potent in the osteosarcoma (OS) lines. With respect to CUR, this derivative showed cytotoxicity at least three times higher in the MTT assay. In addition, in the clonogenic assay, 1 maintained the activity in conditions of long treatment presumably by virtue of its improved stability in biological fluids. Notably, 1 should have improved chemical-physical characteristics of bioavailability with respect to CUR, which should allow for reaching higher blood levels than those observed in the CUR trials. In conclusion, 1 should be considered in future clinical studies on the treatment of OS, either alone or in combination with other medications currently in use.

Ameliorative role of nanocurcumin against the toxicological effects of novel forms of Cuo as nanopesticides: a comparative study

Copper oxide nanoparticles (CuONPs) have a wide range of uses in agricultural applications. Nanocurcumin (NCur) acts as an antioxidant treatment. The goal of the study is to reduce the toxicity resulting from the use of CuONPs as nanopesticides on living organisms by inducing changes in the morphological shape of CuONPs or treating it with NCur. So, we induced a comparative study between three shapes of CuONPs: CuO nanosphere (CuONSp), CuO nanosheet (CuONS), and CuO nanoflower (CuONF). We characterize each nano-form by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (HRTEM), and Zetasizer HT device; 36 rats were divided into six groups (n = 6): 1st group was the control group; 2nd group received 50 mg/kg/day of NCur orally for 30 days; 3rd, 4th, and 5th groups received orally 50 mg/kg/day of CuONSp, CuONS, and CuONF, respectively, for 30 days; 6th group received 50 mg/kg/day CuONSp plus 50 mg/kg/day of NCur orally for 30 days. An elevation occurred in malondialdehyde (MDA), liver and kidney functions, tumor necrosis factor-alpha (TNF-α), and B-cell lymphoma 2 (Bcl2) by CuONSp > CuONS > CuONF, respectively. An inhibition occurred in glutathione (GSH), superoxidase (SOD) catalase (CAT), apoptotic Bax gene (Bax), histopathological, and ultrastructural alterations by CuONSp < CuONS < CuONF, respectively. NCur ameliorated these alternations. In conclusion, CuONF is a better form compared to other forms of nanopesticide in agriculture due to its lower toxicity. NCur decreased the biological alternations which induced by CuONSp due to its antioxidant and anti-apoptotic properties.

Cytotoxicity of Isoxazole Curcumin Analogs on Chronic Myeloid Leukemia-Derived K562 Cell Lines Sensitive and Resistant to Imatinib

Despite curcumin (CUR) inhibiting cell proliferation in vitro by activating apoptotic cell death, its use in pharmacological therapy is hampered by poor solubility, low stability in biological fluids, and rapid removal from the body. Therefore, CUR-derivatives with better biological and chemical-physical characteristics are needed. The bis-ketone moiety of CUR strongly influences its stability in slightly alkaline solutions such as plasma. Here, we considered its replacement with isoxazole, beta-enamine, or oxime groups to obtain more stable derivatives. The evaluation of the chemical-physical characteristics showed that only of the isoxazole derivatives 2 and 22 had better potential than CUR in terms of bioavailability. The UV-visible spectrum analysis showed that derivatives 2 and 22 had better stability than CUR in solutions mimicking the biological fluids. When tested on a panel of cell lines, derivatives 2 and 22 had marked cytotoxicity (IC50 = 0.5 µM) compared with CUR only (IC50 = 17 µM) in the chronic myeloid leukemia (CML)-derived K562 cell line. The derivative 22 was the more selective for CML cells. When administered at the average concentration found for CUR in the blood of patients, derivatives 2 and 22 had potent effects on cell cycle progression and apoptosis initiation, while CUR was ineffective. The apoptotic effect of derivatives 2 and 22 was associated with low necrosis. In addition, derivative 22 was able to reverse drug resistance in K562 cells resistant to imatinib (IM), the reference drug used in CML therapy. The cytotoxicity of derivative 22 on IM-sensitive and resistant cells was associated with upregulation of FOXN3 and CDKN1A expression, G2/M arrest, and triggering of apoptosis. In conclusion, derivative 22 has chemical-physical characteristics and biological effects superior to CUR, which allow us to hypothesize its future use in the therapy of CML and CML forms resistant to IM, either alone or in combination with this drug.

Equine Muscle Derived Mesenchymal Stem Cells Loaded with Water-Soluble Curcumin: Modulation of Neutrophil Activation and Enhanced Protection against Intracellular Oxidative Attack

We investigated the antioxidant potential of equine mesenchymal stem cells derived from muscle microbiopsies (mdMSCs), loaded by a water-soluble curcumin lysinate incorporated into hydroxypropyl-β-cyclodextrin (NDS27). The cell loading was rapid and dependent on NDS27 dosage (14, 7, 3.5 and 1 µM). The immunomodulatory capacity of loaded mdMSCs was evaluated by ROS production, on active and total myeloperoxidase (MPO) degranulation and neutrophil extracellular trap (NET) formation after neutrophil stimulation. The intracellular protection of loaded cells was tested by an oxidative stress induced by cumene hydroperoxide. Results showed that 10 min of mdMSC loading with NDS27 did not affect their viability while reducing their metabolism. NDS27 loaded cells in presence of 14, 7 µM NDS27 inhibited more intensively the ROS production, the activity of the MPO released and bound to the NET after neutrophil stimulation. Furthermore, loaded cells powerfully inhibited intracellular ROS production induced by cumene as compared to control cells or cyclodextrin-loaded cells. Our results showed that the loading of mdMSCs with NDS27 significantly improved their antioxidant potential against the oxidative burst of neutrophil and protected them against intracellular ROS production. The improved antioxidant protective capacity of loaded mdMSCs could be applied to target inflammatory foci involving neutrophils.

Enhanced Anti-Proliferative Effect of Carboplatin in Ovarian Cancer Cells Exploiting Chitosan-Poly (Lactic Glycolic Acid) Nanoparticles

OBJECTIVE

The present article aimed to enhance the therapeutic efficacy of carboplatin (CP) using the formulation of chitosan-poly (lactic glycolic acid) nanoparticles (CS-PLGA NPs).

METHODS

Nanoparticles were synthesized by an ionic gelation method and were characterized for their morphology, particle size, and surface potential measurements by TEM and zeta sizer. This study was highlighted for the evaluation of drug entrapment, loading and in vitro drug release capabilities of the prepared nanoparticles by spectrophotometric analysis. The stability study was also conducted after 3 months for their particle size, zeta potential, drug loading and encapsulation efficiencies. Further, ovarian cancer cell line PEO1 was used to evaluate the toxicity and efficacy of nano-formulation by MTT assay. Additionally, the study was evaluated for apoptosis using flow cytometric analysis.

RESULTS

The CS-PLGA-CP NPs were uniform and spherical in shape. The particle size and zeta potential of CS-PLGA-CP NPs were measured to be 156 ±6.8 nm and +52 ±2.4 mV, respectively. High encapsulation (87.4 ± 4.5%) and controlled retention capacities confirmed the efficiency of the prepared nanoparticles in a time and dose-dependent manner. The cytotoxicity assay results also showed that CS-PLGA-CP NPs have a high efficiency on PEO1 cells compared to the free drug. The flow cytometric result showed 64.25% of the PEO1 cells were apoptotic, and 8.42% were necrotic when treated with CS-PLGA-CP NPs.

CONCLUSION

Chitosan-PLGA combinational polymeric nanoparticles were not only steady but also non-toxic. Our experiments revealed that the chitosan-PLGA nanoparticles could be used as a challenging vehicle candidate for drug delivery for the therapeutic treatment of ovarian cancer.