Topical formulation of quercetin encapsulated in natural lipid nanocarriers: Evaluation of biological properties and phototoxic effect

The Potential Application of Nanocarriers in Delivering Topical Antioxidants

The imbalance in the production of reactive oxygen species (ROS) with endogenous antioxidant capacity leads to oxidative stress, which drives many disorders, especially in the skin. In such conditions, supplementing exogenous antioxidants may help the body prevent the negative effect of ROS. However, the skin, as the outermost barrier of the body, provides a perfect barricade, making the antioxidant delivery complicated. Several strategies have been developed to enhance the penetration of antioxidants through the skin, one of which is nanotechnology. This review focuses on utilizing several nanocarrier systems, including nanoemulsions, liposomes, solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), and polymeric nanoparticles, for transporting antioxidants into the skin. We also reveal ROS formation in the skin and the role of antioxidant therapy, as well as the natural sources of antioxidants. Furthermore, we discuss the clinical application of topical antioxidant therapy concomitantly with the current status of using nanotechnology to deliver topical antioxidants. This review will accelerate the advancement of topical antioxidant therapy.

Lipid Nanovesicles for Antioxidant Delivery in Skin: Liposomes, Ufasomes, Ethosomes, and Niosomes

The skin, being the largest organ of the human body, serves as the primary barrier against external insults, including UV radiation, pollutants, and microbial pathogens. However, prolonged exposure to these environmental stressors can lead to the generation of reactive oxygen species (ROS), causing oxidative stress, inflammation, and ultimately, skin aging and diseases. Antioxidants play a crucial role in neutralizing ROS and preserving skin health by preventing oxidative damage. In recent years, nanotechnology has emerged as a powerful tool for enhancing the delivery of antioxidants onto the skin. In particular, liposomal formulations have offered unique advantages such as improved stability, controlled release, and enhanced penetration through the skin barrier. This has led to a surge in research focused on developing liposomal-based antioxidant delivery systems tailored for skin health applications. Through a comprehensive analysis of the literature from the 2019-2024 period, this review provides an overview of emerging trends in the use of liposomal delivery systems developed for antioxidants aimed at improving skin health. It explores the latest advancements in liposomal formulation strategies, vesicle characterization, and their applications in delivering antioxidants to combat oxidative stress-induced skin damage and other associated skin pathologies. A comparison of various delivery systems is conducted for the most common antioxidants. Finally, a brief analysis of lipid nanovesicles used in the cosmeceutical industry is provided.

Evaluation of the photoprotective and antioxidant potential of an avobenzone derivative

Solar radiation can cause damage to the skin, and the use of sunscreens is one of the main protective measures. However, photounstable ultraviolet (UV) filters can generate photoproducts and reactive oxygen species (ROS). Adding antioxidants, such as resveratrol, to enhance the action of UV filters in sunscreens is an interesting strategy for reducing the damage caused by UV radiation exposure. However, new compounds must have their stability, safety and efficacy guaranteed. Avobenzone, a commonly used UV filter, stands out as a promising candidate for structural modification to enhance its stability. Its molecular hybridization with other UV filters and antioxidants can lead to safer and more effective compounds. In this study, the photoprotective and antioxidant potential of a derivative of avobenzone, hybridized with resveratrol's molecule, was evaluated using in vitro models of cells in monolayer and reconstructed human skin (RHS). Phototoxic potential was assessed using fibroblasts, while the antioxidant activity was measured using the DCFH2-DA probe in HaCaT keratinocytes and in-house RHS. The derivative exhibited UV absorption and demonstrated photostability. It did not exhibit any phototoxic nor photoreactivity potential. Additionally, it was able to photo stabilize a combination of photounstable UV filters, avobenzone and octyl methoxycinnamate, and to reduce their phototoxic potential. In terms of antioxidant activity, the derivative successfully protected against UVA-induced ROS production in the HaCaT keratinocytes model, showing statistical equivalence to the antioxidant control, quercetin (10 μg/mL). Furthermore, experiments conducted in the RHS model demonstrated a significant reduction of 30.7% in ROS generation compared to the irradiated control. This study demonstrated that structural modifications of avobenzone can lead to the development of a broad spectrum (absorbing UVB and UVA II radiation, as well as a portion of the UVA I radiation), non-phototoxic, non-photoreactive and photostable derivative for sunscreen and anti-aging formulations. This derivative enhances protection against oxidative stress induced by UV radiation and improves the effectiveness of sun protection. In addition to the monolayer model, the use of a standardized in-house RHS model was highly relevant for evaluating the effects of UV radiation and skin aging. This model closely mimics human physiological conditions and enables the testing of new compounds and the investigation of protective mechanisms against skin damage.

From Traditional Medicine to Advanced Therapeutics: The Renaissance of Phyto-nano Interventions in Psoriasis

Psoriasis is an autoimmune systemic chronic inflammatory disease that exhibits characteristic detrimental effects on the skin, often leading to infections or comorbid conditions. The multifaceted nature of psoriasis has made it very challenging to treat, especially with current chemotherapy options. Therefore, it is essential to consider phytoconstituents as novel alternatives. However, despite demonstrating higher anti-inflammatory, anti-psoriasis, and immunomodulatory potential, their clinical usage is hindered due to their poor physicochemical properties. To address these drawbacks, nanoparticulate drug delivery systems have been developed, helping to achieve better permeation of phytoconstituents through topical administration. This has breathed new life into traditional systems of medicine, particularly in the context of treating psoriasis. In this current review, we present a detailed, comprehensive, and up-to-date analysis of the literature, which will contribute to affirming the clinical role of phyto-nano interventions against psoriasis.

Assessment of the photoprotective potential and structural characterization of secondary metabolites of Antarctic fungus Arthrinium sp

Interest in Antarctic fungi has grown due to their resilience in harsh environments, suggesting the presence of valuable compounds from its organisms, such as those presenting photoprotective potential, since this environment suffers the most dangerous UV exposure in the world. Therefore, this research aimed to assess the photoprotective potential of compounds from sustainable marine sources, specifically seaweed-derived fungi from Antarctic continent. These studies led to discovery of photoprotective and antioxidant properties of metabolites from Arthrinium sp., an endophytic fungus from Antarctic brown algae Phaeurus antarcticus. From crude extract, fractions A-I were obtained and compounds 1-6 isolated from E and F fractions, namely 3-Hydroxybenzyl alcohol (1), (-)-orthosporin (2), norlichexanthone (3), anomalin B (4), anomalin A (5), and agonodepside B (6). Compounds 1, 2, and 6 were not previously reported in Arthrinium. Fraction F demonstrated excellent absorbance in both UVA and UVB regions, while compound 6 exhibited lower UVB absorbance, possibly due to synergistic effects. Fraction F and compound 6 displayed photostability and were non-phototoxic to HaCaT cells. They also exhibited antioxidant activity by reducing intracellular ROS production induced by UVA in keratinocyte monolayers and reconstructed human skin models (resulting in 34.6% and 30.2% fluorescence reduction) and did not show irritation potential in HET-CAM assay. Thus, both are promising candidates for use in sunscreens. It is noted that Fraction F does not require further purification, making it advantageous, although clinical studies are necessary to confirm its potential applicability for sunscreen formulations.

Design of Quercetin-Loaded Natural Oil-Based Nanostructured Lipid Carriers for the Treatment of Bacterial Skin Infections

The biological activity of natural plant-oil-based nanostructured lipid carriers (NPO-NLCs) can be enhanced by the encapsulation of bioactive compounds, and they in turn can improve topical delivery of the drugs. Quercetin (QR), a vital plant flavonoid, expresses antibacterial properties, and we recently showed that empty NPO-NLCs also have antimicrobial activity. The main objective of this study was to evaluate the synergetic effect of loading natural plant-oil-based nanostructured lipid carriers with quercetin (QR-NPO-NLCs) as a topical delivery system for the treatment of bacterial skin infections. Five nanostructured lipid carrier systems containing different oils (sunflower, olive, corn, coconut, and castor) were engineered. The particles’ stability, structural properties, bioavailability, and antimicrobial activity were studied. NLCs with an average size of <200 nm and Z-potential of −40 mV were developed. Stable QR-NPO-NLCs were obtained with high encapsulation efficiency (>99%). The encapsulation of QR decreased cytotoxicity and increased the antioxidant effect of nanocarriers. An increase in antibacterial activity of the systems containing QR was demonstrated against Staphylococcus aureus. QR-NPO-NLCs could transport QR to an intranuclear location within HaCaT cells, indicating that QR-NPO-NLCs are promising candidates for controlled topical drug delivery.

Antimicrobial benefits of flavonoids and their nanoformulations

Abstract:

Nowadays, there is an urgent need to discover and develop long-term and effective antimicrobial and biofilm-inhibiting compounds. Employing combination therapies using novel drug delivery systems and also natural antimicrobial substances is a promising strategy in this field. Nanoparticles (NPs)-based materials have become well appreciated in recent times due to serve as antimicrobial agents or the carriers for promoting the bioavailability and effectiveness of antibiotics. Flavonoids belong to the promising groups of bioactive compounds abundantly found in fruits, vegetables, spices, and medicinal plants with strong antimicrobial features. Flavonoids and NPs have potential as alternatives to the conventional antimicrobial agents, both on their own as well as in combination. Different classes of flavonoid NPs may be particularly advantageous in handling microbial infections. The most important antimicrobial mechanisms of flavonoid NPs include oxidative stress induction, non-oxidative mechanisms, and metal ion release. However, the efficacy of flavonoid NPs against pathogens and drug-resistant pathogens changes according to their physicochemical characteristics as well as the particular structure of microbial cell wall and enzymatic composition. In this review, we provide an outlook on the antimicrobial mechanism of flavonoid-based NPs and the crucial factors that are involved.

Design and development of topical liposomal formulations in a regulatory perspective

The skin is the absorption site for drug substances intended to treat loco-regional diseases, although its barrier properties limit the permeation of drug molecules. The growing knowledge of the skin structure and its physiology have supported the design of innovative nanosystems (e.g. liposomal systems) to improve the absorption of poorly skin-permeable drugs. However, despite the dozens of clinical trials started, few topically applied liposomal systems have been authorized both in the EU and the USA. Indeed, the intrinsic complexity of the topically applied liposomal systems, the higher production costs, the lack of standardized methods and the more stringent guidelines for assessing their benefit/risk balance can be seen as causes of such inefficient translation. The present work aimed to provide an overview of the physicochemical and biopharmaceutical characterization methods that can be applied to topical liposomal systems intended to be marketed as medicinal products, and the current regulatory provisions. The discussion highlights how such methodologies can be relevant for defining the critical quality attributes of the final product, and they can be usefully applied based on the phase of the life cycle of a liposomal product: to guide the formulation studies in the early stages of development, to rationally design preclinical and clinical trials, to support the pharmaceutical quality control system and to sustain post-marketing variations. The provided information can help define harmonized quality standards able to overcome the case-by-case approach currently applied by regulatory agencies in assessing the benefit/risk of the topically applied liposomal systems.

Hybrid Nanoparticles as an Efficient Porphyrin Delivery System for Cancer Cells to Enhance Photodynamic Therapy

Photodynamic therapy (PDT) is a potential non-invasive approach for application in oncological diseases, based on the activation of a photosensitizer (PS) by light at a specific wavelength in the presence of molecular oxygen to produce reactive oxygen species (ROS) that trigger the death tumor cells. In this context, porphyrins are interesting PS because they are robust, have high chemical, photo, thermal, and oxidative stability, and can generate singlet oxygen (1O2). However, porphyrins exhibit low solubility and a strong tendency to aggregate in a biological environment which limits their clinical application. To overcome these challenges, we developed hybrid nanostructures to immobilize 5,10,15,20-tetrakis[(4-carboxyphenyl) thio-2,3,5,6-tetrafluorophenyl] (P), a new third-generation PS. The biological effect of this system was evaluated against bladder cancer (BC) cells with or without light exposition. The nanostructure composed of lipid carriers coated by porphyrin-chitosan (P-HNP), presented a size of ca. 130 nm and low polydispersity (ca. 0.25). The presence of the porphyrin-chitosan (P-chitosan) on lipid nanoparticle surfaces increased the nanoparticle size, changed the zeta potential to positive, decreased the recrystallization index, and increased the thermal stability of nanoparticles. Furthermore, P-chitosan incorporation on nanoparticles increased the stability and enhanced the self-organization of the system and the formation of spherical structures, as observed by small-angle X-ray scattering (SAXS) analysis. Furthermore, the immobilization process maintained the P photoactivity and improved the photophysical properties of PS, minimizing its aggregation in the cell culture medium. In the photoinduction assays, the P-HNP displayed high phototoxicity with IC50 3.2-folds lower than free porphyrin. This higher cytotoxic effect can be correlated to the high cellular uptake of porphyrin immobilized, as observed by confocal images. Moreover, the coated nanoparticles showed mucoadhesive properties interesting to its application in vivo. Therefore, the physical and chemical properties of nanoparticles may be relevant to improve the porphyrin photodynamic activity in BC cells.

In Vitro Evaluation of the Photoprotective Potential of Quinolinic Alkaloids Isolated from the Antarctic Marine Fungus Penicillium echinulatum for Topical Use

Marine-derived fungi proved to be a rich source of biologically active compounds. The genus Penicillium has been extensively studied regarding their secondary metabolites and biological applications. However, the photoprotective effects of these metabolites remain underexplored. Herein, the photoprotective potential of Penicillium echinulatum, an Antarctic alga-associated fungus, was assessed by UV absorption, photostability study, and protection from UVA-induced ROS generation assay on human immortalized keratinocytes (HaCaT) and reconstructed human skin (RHS). The photosafety was evaluated by the photoreactivity (OECD TG 495) and phototoxicity assays, performed by 3T3 neutral red uptake (3T3 NRU PT, OECD TG 432) and by the RHS model. Through a bio-guided purification approach, four known alkaloids, (-)-cyclopenin (1), dehydrocyclopeptine (2), viridicatin (3), and viridicatol (4), were isolated. Compounds 3 and 4 presented absorption in UVB and UVA-II regions and were considered photostable after UVA irradiation. Despite compounds 3 and 4 showed phototoxic potential in 3T3 NRU PT, no phototoxicity was observed in the RHS model (reduction of cell viability < 30%), which indicates their very low acute photoirritation and high photosafety potential in humans. Viridicatin was considered weakly photoreactive, while viridicatol showed no photoreactivity; both compounds inhibited UVA-induced ROS generation in HaCaT cells, although viridicatol was not able to protect the RHS model against UVA-induced ROS production. Thus, the results highlighted the photoprotective and antioxidant potential of metabolites produced by P. echinulatum which can be considered a new class of molecules for photoprotection, since their photosafety and non-cytotoxicity were predicted using recommended in vitro methods for topical use.

Design, Preparation, and Characterization of Effective Dermal and Transdermal Lipid Nanoparticles: A Review

Limited permeability through the stratum corneum (SC) is a major obstacle for numerous skin care products. One promising approach is to use lipid nanoparticles as they not only facilitate penetration across skin but also avoid the drawbacks of conventional skin formulations. This review focuses on solid lipid nanoparticles (SLNs), nanostructured lipid nanocarriers (NLCs), and nanoemulsions (NEs) developed for topical and transdermal delivery of active compounds. A special emphasis in this review is placed on composition, preparation, modifications, structure and characterization, mechanism of penetration, and recent application of these nanoparticles. The presented data demonstrate the potential of these nanoparticles for dermal and transdermal delivery.

Synthesis and characterization of an experimental primer containing chitosan nanoparticles - Effect on the inactivation of metalloproteinases, antimicrobial activity and adhesive strength

OBJECTIVE

The aim of this study was to synthesize and characterize an experimental primer containing cationic lipid nanoparticles (NPL-chitosan) and to evaluate its properties.

DESIGN

The NPL-chitosan were synthesized by emulsion and sonication method. The experimental primers were applied in dentin surface of fifty human molars. The experimental groups were: 1) application of commercial primer; 2) Primer containing 2% of Chlorhexidine (CHX) 3); Primer with 2% NPL-chitosan 4); Primer with 0.6 % of NPL-chitosan 5); Primer with 0.4 % of NPL-chitosan. A composite resin plateau was used for the analysis, where sections were made for making the dentin beams. The effect of experimental primer with cationic nanoparticles in the inhibition of matrix metalloproteinase (MMP) activity was carrying out by in situ zymography. For the Resin-Dentin Adhesive Strength and in situ Zymography analysis, was used the One-way analysis of variance (ANOVA) with significance level of 95 %.

RESULTS

Spherical NPL-chitosan presented size below 220 nm, polydispersity index of 0.179 and zeta potential positive and was stable over 75 days. These nanoparticles showed antibacterial activity agsainst S. mutans with MIC of the 0.4 % and MBC of 0.67 %. In the Microtensile Strength, no statistical difference was observed between the experimental groups (p = 0.9054). The in situ zymography assay showed that the group with 2% of NPL-chitosan presented higher inactivation activity of MMPs compared to the other groups (p < 0.05).

CONCLUSION

The experimental primer containing NPL-chitosan has antimicrobial activity, does not alter the adhesive resistance and inactivates MMPs present in dentin.

Anti-rheumatic effect of quercetin and recent developments in nano formulation

Quercetin is a potential anti-rheumatoid drug. Nano formulation strategies could improve its solubility and efficacy.

Development of Photoprotective Formulations Containing Nanostructured Lipid Carriers: Sun Protection Factor, Physical-Mechanical and Sensorial Properties

The effects of ultraviolet (UV) radiation emitted by the sun are cumulative and can result in chemical changes such as the generation of reactive oxygen species (ROS), leading to the regular use of sunscreen. As an alternative, the use of antioxidants, such as quercetin, into sunscreen can control these effects and provide additional skin photoprotection. However, quercetin presents low stability and poor permeation, alternatively, the encapsulation in nanoparticles can improve the stability and skin permeation. Thus, this study aimed to develop photoprotective formulations containing nanoencapsulated quercetin, characterize the physical-mechanical and sensorial properties, and evaluate the influence of nanocarriers on sun protection factor (SPF) and the immediate clinical effects. Sunscreen formulations with or without antioxidants in a free form or loaded in nanostructured lipid carriers (NLCs) were developed. After the stability, rheological behavior, texture profile, and in vivo SPF (sun protector factor) evaluation, sixty female participants, aged between 20 and 35 years, were enclosed to evaluate the sensorial properties and immediate clinical effects of the formulation in the skin hydration using biophysical and skin imaging techniques. The correlation of rheological behavior, texture profile, and sensory properties enabled the correct choice of formulation ingredients. In addition, the use of NLCs with quercetin significantly improved the SPF in vivo of the developed photoprotective formulation, without increasing the amount of UV filters. Finally, the association of NLCs in the photoprotective formulation showed synergistic effects in the SPF and an improvement in the skin barrier function and hydration.

Recent Advances in the Structural Design of Photosensitive Agent Formulations Using "Soft" Colloidal Nanocarriers

The growing demand for effective delivery of photosensitive active compounds has resulted in the development of colloid chemistry and nanotechnology. Recently, many kinds of novel formulations with outstanding pharmaceutical potential have been investigated with an expansion in the design of a wide variety of "soft" nanostructures such as simple or multiple (double) nanoemulsions and lipid formulations. The latter can then be distinguished into vesicular, including liposomes and "smart" vesicles such as transferosomes, niosomes and ethosomes, and non-vesicular nanosystems with solid lipid nanoparticles and nanostructured lipid carriers. Encapsulation of photosensitive agents such as drugs, dyes, photosensitizers or antioxidants can be specifically formulated by the self-assembly of phospholipids or other amphiphilic compounds. They are intended to match unique pharmaceutic and cosmetic requirements and to improve their delivery to the target site via the most common, i.e., transdermal, intravenous or oral administration routes. Numerous surface modifications and functionalization of the nanostructures allow increasing their effectiveness and, consequently, may contribute to the treatment of many diseases, primarily cancer. An increasing article number is evidencing significant advances in applications of the different classes of the photosensitive agents incorporated in the "soft" colloidal nanocarriers that deserved to be highlighted in the present review.

Encapsulating plant ingredients for dermocosmetic application: an updated review of delivery systems and characterization techniques

Today, there is a rising demand and ongoing search for novel plant-derived phytochemicals in the cosmetic market owing to the growing consumer expectations worldwide for green and natural health products. Various plant ingredients, including polyphenols, oils, volatile oils, vitamins and other herbal extracts, have been extensively used in herbal cosmetics. Recent advances in encapsulation technologies have greatly improved their chemical stability, biocompatibility, skin permeability and dermocosmetic efficiency when applied topically. This comprehensive review summarizes the up-to-date information on encapsulated plant ingredients tailored for dermocosmetic application with a focus on the development of novel delivery systems. An overview of the commonly used techniques for carrier characterization, performance-related properties and toxicological evaluation is also included, which might provide guidance for researchers to select or develop appropriate assay systems.