Proniosomal Gel for Topical Delivery of Rutin: Preparation, Physicochemical Characterization and In Vitro Toxicological Profile Using 3D Reconstructed Human Epidermis Tissue and 2D Cells

Development of Curcumin and Turmerone Loaded Solid Lipid Nanoparticle for Topical Delivery: Optimization, Characterization and Skin Irritation Evaluation with 3D Tissue Model

Background

Curcuma longa L., commonly known as turmeric, is renowned for its therapeutic benefits attributed to bioactive compounds, namely curcumin (Cur) and aromatic turmerone (Tur), present in its rhizome. These compounds exhibit diverse therapeutic properties, including anti-inflammatory, antioxidant, and anti-tumor effects. However, the topical application of these compounds has a significant potential for inducing skin irritation. This study focuses on formulating solid lipid nanoparticle (SLN) carriers encapsulating both Cur and Tur for reduced irritation and enhanced stability.

Methods

SLN formulations were prepared by a method using homogenization followed by ultrasonication procedures and optimized by applying response surface methodology (RSM).

Results

The optimized SLN formulation demonstrated entrapment efficiencies, with 77.21 ± 4.28% for Cur and 75.12 ± 2.51% for Tur. A size distribution of 292.11 ± 9.43 nm was obtained, which was confirmed to be a spherical and uniform shape via environmental scanning electron microscopy (ESEM) images. The in vitro release study indicated cumulative releases of 71.32 ± 3.73% for Cur and 67.23 ± 1.64% for Tur after 24 hours under sink conditions. Physical stability tests confirmed the stability of formulation, allowing storage at 4°C for a minimum of 60 days. Notably, in vitro skin irritation studies, utilizing the reconstructed human epidermal model (EPI-200-SIT), revealed a significant reduction in irritation with the SLN containing Cur and Tur compared to nonencapsulated Cur and Tur.

Conclusion

These findings collectively endorse the optimized SLN formulation as a favorable delivery system for Cur and Tur in diverse topical uses, offering enhanced stability, controlled release and reduced irritation.

Rutin Gel with Bone Graft Accelerates Bone Formation in a Rabbit Model by Inhibiting MMPs and Enhancing Collagen Activities

Bone graft techniques are used to compensate for bone loss in areas with deficient regeneration. However, matrix metalloproteases (MMPs) can limit bone formation by degrading extracellular matrices, which are required for bone regrowth. Noteworthily, rutin is a natural flavonoid compound that inhibits the genetic expression of various MMPs. Therefore, rutin may serve as an inexpensive and stable alternative to the growth factors used to accelerate dental bone graft healing. This study aimed to evaluate the potential of mixing rutin gel with allograft bone to accelerate the healing of bone defects in an in vivo rabbit model. Bone defects were surgically induced in New Zealand rabbits (n = 3 per group) and subsequently treated with bone grafts along with rutin or control gel. Overall, treatment with rutin significantly prevented the expression of several MMPs and increased type III collagen in the gingiva around the surgical site. Additionally, rutin-treated animals showed enhanced bone formation with higher bone marrow content in the jawbone defect area compared with the control group. Taken together, these findings demonstrate that rutin gel, when added to bone grafts, quickly enhances bone formation and may serve as a suitable alternative to expensive growth factors for the same purpose.

Structural Characterization and Optimization of a Miconazole Oral Gel

The development of semisolid formulations, gels in particular, has raised the attention of scientists more and more over the last decades. Because of their biocompatibility, hydrophilic nature, and capacity of absorbing large quantities of water, hydrogels are still one of the most promising pharmaceutical formulations in the pharmaceutical industry. The purpose of this study is to develop an optimal formulation capable of incorporating a water-poorly soluble active ingredient such as miconazole used in the treatment of fungal infections with Candida albicans and Candida parapsilosis. A D-optimal design was applied to study the relationship between the formulation parameter and the gel characteristics. The independent parameters used in this study were the Carbopol 940 concentration (the polymer used to obtain the gel matrix), the sodium hydroxide amount, and the presence/absence of miconazole. Ten different dependent parameters (Y1-Y10) were evaluated (penetrometry, spreadability, viscosity, and tangential tension at 1 and 11 levels of speed whilst destructuring and during the reorganization of the gel matrix). The consistency of the gels ranged from 23.2 mm (GO2) to 29.6 mm (GM5). The least spreadable gel was GO7 (1384 mm²), whilst the gel that presented the best spreadability was GO1 (3525 mm²). The viscosity and the tangential stress at the selected levels (1 and 11) varied due to the different compositions of the proposed gels. The gels were also tested for drug content and antifungal activity. All determinations had satisfying results; the drug content was within limits accepted by Ph. Eur. 10 and all formulations containing miconazole exhibited antifungal activity. An optimal formulation with miconazole was attained, consisting of 0.84% Carbopol 940 and 0.32% sodium hydroxide.

Oxidative Stability and Protective Effect of the Mixture between Helianthus annuus L. and Oenothera biennis L. Oils on 3D Tissue Models of Skin Irritation and Phototoxicity

The present study was aimed to evaluate the oxidative stability as well as to assess the protective effect of the mixture of Helianthus annuus L. (HAO) and Oenothera biennis L. (OBO) oils on 3D tissue models of skin irritation and phototoxicity. The following methods were used: GS analysis (fatty acids composition), thiobarbituric acid-reactive substances assay (TBA) (lipid oxidation degree of tested samples), 3D EpiDerm models (skin irritation and phototoxicity). For HAO the detected saturated fatty acids (SFA) were palmitic acid (7.179%), stearic acid (3.586%), eicosanoic (0.138%) and docosanoic acid (0.548%) The monounsaturated acids (MUFA) were palmitoleic acid (0.158%) and oleic acid (28.249%) and the polyunsaturated acids (PUFA) were linoleic acid (59.941%) and linolenic acid (0.208%). For OBO the detected SFA were myristic acid (0.325%), pentadecylic acid (0.281%), palmitic (7.2%), stearic (2.88%), and arachidic acid (0.275%). Regarding MUFA, even a lower proportion (8.196%) was observed, predominantly being oleic acid, cis form (7.175%), oleic (n10) (0.558%) and 11-eicosenoic (0.210%) acids. The higher content was found for PUFA (82.247%), the most significant proportions being linoleic acid (72.093%), arachidonic acid (9.812%) and linolenic (0.233%). Obtained data indicate a good oxidative stability and biocompatibility of the mixture on the 3D EpiDerm models with no irritant and no phototoxic effects. Oenothera biennis L. oil may be an excellent natural choice in order to delay or prevent oxidative damage of Helianthus annuus L. oil.

Rutin bioconjugates as potential nutraceutical prodrugs: An in vitro and in ovo toxicological screening

Rutin (RUT) is considered one the most attractive flavonoids from a therapeutic perspective due to its multispectral pharmacological activities including antiradical, anti-inflammatory, antiproliferative, and antimetastatic among others. Still, this compound presents a low bioavailability what narrows its clinical applications. To overcome this inconvenience, the current paper was focused on the synthesis, characterization, and toxicological assessment of two RUT bioconjugates obtained by enzymatic esterification with oleic acid (OA) and linoleic acid (LA)—rutin oleate (RUT-O) and rutin linoleate (RUT-L), as flavonoid precursors with improved physicochemical and biological properties. Following the enzymatic synthesis in the presence of Novozyme® 435, the two bioconjugates were obtained, their formation being confirmed by RAMAN and FT-IR spectroscopy. The in vitro and in ovo toxicological assessment of RUT bioconjugates (1–100 µM) was performed using 2D consecrated cell lines (cardiomyoblasts - H9c2(2-1), hepatocytes—HepaRG, and keratinocytes—HaCaT), 3D reconstructed human epidermis tissue (EpiDerm™), and chick chorioallantoic membranes, respectively. The results obtained were test compound, concentration—and cell-type dependent, as follows: RUT-O reduced the viability of H9c2(2-1), HepaRG, and HaCaT cells at 100 µM (to 77.53%, 83.17%, and 78.32%, respectively), and induced cell rounding and floating, as well as apoptotic-like features in the nuclei of all cell lines, whereas RUT-L exerted no signs of cytotoxicity in all cell lines in terms of cell viability, morphology, and nuclear integrity. Both RUT esters impaired the migration of HepaRG cells (at 25 µM) and lack irritative potential (at 100 µM) in vitro (tissue viability >50%) and in ovo (irritation scores of 0.70 for RUT-O, and 0.49 for RUT-L, respectively). Computational predictions revealed an increased lipophilicity, and reduced solubility, drug-likeness and drug score of RUT-O and RUT-L compared to their parent compounds—RUT, OA, and LA. In conclusion, we report a favorable toxicological profile for RUT-L, while RUT-O is dosage-limited since at high concentrations were noticed cytotoxic effects.

Tea Tree Oil Nanoemulsion-Based Hydrogel Vehicle for Enhancing Topical Delivery of Neomycin

The present investigation aims to improve the antimicrobial influence of certain antibacterial drugs, namely, neomycin (NEO), exploiting the benefits of natural oils such as tea tree oil (TTO). Therefore, a distinctive nanolipid formulation, namely, a nanoemulsion (NE), was developed using a Central Composite Factorial Design (CCD) approach depending on the amount of TTO and tween 80 as surfactant. The optimized NEO-NE formula exhibiting minimum globular size and maximum in vitro release was selected. For efficient topical delivery, NEO-NE was incorporated into a pre-formulated hydrogel. The developed NEO-NE-hydrogel was characterized by its physical characteristics such as pH, viscosity, and spreadability. Next, it was tested for stability under different conditions for 3 months. Ultimately, an irritation test was conducted followed by an antibacterial examination. The preparation demonstrated acceptable properties to be successfully applied topically. It showed non-significant changes in stability in both conditions up to 3 months storage when compared to a fresh preparation. It exhibited no irritation when applied on hairless animal skin. Finally, TTO revealed a good inhibition for the bacterial growth that could improve the influence of NEO antibacterial activity, indicating the efficiency of NE containing NEO prepared with TTO to be a promising antibacterial nanocarrier.

Toxicological Assessment of an Acrylic Removable Orthodontic Appliance Using 2D and 3D In Vitro Methods

Malocclusion is a global health problem, mainly affecting children and adolescents. For this reason, orthodontic treatment must be, on the one hand, safe, non-toxic, and effective and, on the other hand, it must have the best possible esthetic profile. Thus, the use of orthodontic appliances is addressed to all age groups, including young children, for a long period of time, which is why their safety profile is a matter of real interest. For this reason, the purpose of the present study was to evaluate the safety and biocompatibility of an acrylic removable orthodontic appliance made of polymethylmethacrylate and stainless steel alloy made by our team of researchers. To verify the biocompatibility of the medical device, it was immersed in artificial saliva with three different pHs (3, 7, and 10) for a period of ten days. Subsequently, the three types of saliva were tested on human keratinocytes (HaCaT cell line) in terms of viability and modification of cell morphology. Finally, the use of 3D reconstructed human epidermis verified the cytotoxic and irritating potential of the medical device, thus providing relevant information regarding its biocompatibility. The results revealed that by maintaining the orthodontic device in the saliva there is no release of substances with a toxic effect on the human keratinocytes and on the 3D reconstructed human epidermis. There were also no significant changes in cell morphology. In conclusion, it is suggested that the acrylic removable appliance has a safety profile recommended for in vivo use.

Methotrexate and Cetuximab—Biological Impact on Non-Tumorigenic Models: In Vitro and In Ovo Assessments

Background Objectives: The neoplastic process remains a major health problem facing humanity. Although there are currently different therapeutic options, they raise a multitude of shortcomings related to the toxic effects associated with their administration. Methotrexate (Met) and Cetuximab (Cet) are two basic chemotherapeutics used in cancer practice, but notwithstanding despite many years of use, the mechanisms by which the multitude of side-effects occur are not yet fully understood. Thus, the present study focused on the in vitro and in ovo evaluation of the associated toxic mechanisms on keratinocytes, keys cells in the wound healing process. Materials and Methods: The two chemotherapeutics were tested in eight different concentrations to evaluate keratinocytes viability, the anti-migratory effect, and the influence on the expression of markers involved in the production of cell apoptosis. In addition, the potential irritating effect on the vascular plexus were highlighted by applying the in ovo method, chick chorioallantoic membrane (HET-CAM). Results: The results revealed that Met induced decreased cell viability as well as increased expression of pro-apoptotic genes. In the vascular plexus of the chorioallantoic membrane, Met caused vascular irritation accompanied by capillary hemorrhage and vascular stasis. Conclusions: Summarizing, Cet presents a safer toxicological profile, compared to Met, based on the results obtained from both in vitro (cell viability, wound healing, RT-PCR assays), and in ovo (HET-CAM assay) techniques.

Rutin Exerts Cytotoxic and Senescence-Inducing Properties in Human Melanoma Cells

Malignant melanoma represents the deadliest type of skin cancer with narrow treatment options in advanced stages. Herbal constituents possessing anticancer properties occupy a particular spot in melanoma research as potential chemotherapeutics. Rutin (RUT) is a natural compound exerting antioxidant, antimicrobial, anti-inflammatory, UV-filtering, and SPF-enhancing activities that are beneficial to the skin; however, its effect as an anti-melanoma agent is less investigated. The current study is focused on assessing the cytotoxic potential of RUT against two different human melanoma cell lines: RPMI-7951 and SK-MEL-28 by evaluating its impact in terms of cell viability, cells’ morphology, and nuclear aspect assessment, and senescence-inducing properties. The results indicate a dose-dependent decrease in the viability of both cell lines, with calculated IC₅₀ values of 64.49 ± 13.27 µM for RPMI-7951 cells and 47.44 ± 2.41 µM for SK-MEL-28, respectively, accompanied by a visible reduction in the cell confluency and apoptotic features within the cell nuclei. RUT exerted a senescence-inducing property highlighted by the elevated expression of senescent-associated beta-galactosidase (SA-β-gal) in SK-MEL-28 cells. Despite the in vitro anti-melanoma effect revealed by our results, further studies are required to elucidate the mechanisms of RUT-induced cytotoxicity and senescence in melanoma cells.

Rutin: A Flavonoid as an Effective Sensitizer for Anticancer Therapy; Insights into Multifaceted Mechanisms and Applicability for Combination Therapy

Rutin is a unique antioxidant flavonoid that is mainly found in fruit, vegetables, cereals, and many other plant-based human diets. This review aims to highlight the in vitro anticancer properties of rutin including combination therapeutic strategies. Literature resources were gathered through PubMed, Scopus, Web of Science, and Google Scholar databases that cover the period of 1995–2021. Rutin is demonstrated to inhibit the proliferation of breast, colon, lung, and prostate cancers and other tumors. Furthermore, rutin alone or in combination with other therapeutic agents has been shown to regulate several signalling pathways involving the Ras/Raf and PI3K/Akt, MAPK, and TGF-β2/Smad2/3Akt/PTEN, etc., which are related to the processes of carcinogenesis and induction of apoptosis. The combination of rutin with other chemotherapy drugs may benefit on prevention of tumor cells by decreasing drug resistance and chemotherapy side effects. Moreover, rutin induces apoptosis synergistically with the therapeutic agent. More in vivo and clinical data are however needed to evaluate the true potential of rutin as an anticancer agent as an adjuvant. The present review highlights the effects of rutin which can be a promising candidate in combination with other antitumor drugs or alone for cancer treatment in vitro. Also, rutin can lead to decrease in drug resistance and chemotherapeutic side effects.

Oleogel Formulations for the Topical Delivery of Betulin and Lupeol in Skin Injuries-Preparation, Physicochemical Characterization, and Pharmaco-Toxicological Evaluation

The skin integrity is essential due to its pivotal role as a biological barrier against external noxious factors. Pentacyclic triterpenes stand as valuable plant-derived natural compounds in the treatment of skin injuries due to their anti-inflammatory, antioxidant, antimicrobial, and healing properties. Consequently, the primary aim of the current investigation was the development as well as the physicochemical and pharmaco-toxicological characterization of betulin- and lupeol-based oleogels (Bet OG and Lup OG) for topical application in skin injuries. The results revealed suitable pH as well as organoleptic, rheological, and textural properties. The penetration and permeation of Bet and Lup oleogels through porcine ear skin as well as the retention of both oleogels in the skin were demonstrated through ex vivo studies. In vitro, Bet OG and Lup OG showed good biocompatibility on HaCaT human immortalized cells. Moreover, Bet OG exerted a potent wound-healing property by stimulating the migration of the HaCaT cells. The in ovo results demonstrated the non-irritative potential of the developed formulations. Additionally, the undertaken in vivo investigation indicated a positive effect of oleogels treatment on skin parameters by increasing skin hydration and decreasing erythema. In conclusion, oleogel formulations are ideal for the local delivery of betulin and lupeol in skin disorders.

Enhancement of the Antioxidant and Skin Permeation Properties of Betulin and Its Derivatives

This study investigated the antioxidant activity DPPH, ABTS, and Folin-Ciocalteu methods of betulin (compound 1) and its derivatives (compounds 2-11). Skin permeability and accumulation associated with compounds 1 and 8 were also examined. Identification of the obtained products (compound 2-11) and betulin isolated from plant material was based on the analysis of 1H- NMR and 13C-NMR spectra. The partition coefficient was calculated to determine the lipophilicity of all compounds. In the next stage, the penetration through pig skin and its accumulation in the skin were evaluated of ethanol vehicles containing compound 8 (at a concentration of 0.226 mmol/dm3), which was characterized by the highest antioxidant activity. For comparison, penetration studies of betulin itself were also carried out. Poor solubility and the bioavailability of pure compounds are major constraints in combination therapy. However, we observed that the ethanol vehicle was an enhancer of skin permeation for both the initial betulin and compound 8. The betulin 8 derivative showed increased permeability through biological membranes compared to the parent betulin. The paper presents the transformation of polycyclic compounds to produce novel derivatives with marked antioxidant activities and as valuable intermediates for the pharmaceutical industry. Moreover, the compounds contained in the vehicles, due to their mechanism of action, can have a beneficial effect on the balance between oxidants and antioxidants in the body, minimizing the effects of oxidative stress. The results of this work may contribute to knowledge regarding vehicles with antioxidant potential. The use of vehicles for this type of research is therefore justified.

Assessment of Betulinic Acid Cytotoxicity and Mitochondrial Metabolism Impairment in a Human Melanoma Cell Line

Melanoma represents one of the most aggressive and drug resistant skin cancers with poor prognosis in its advanced stages. Despite the increasing number of targeted therapies, novel approaches are needed to counteract both therapeutic resistance and the side effects of classic therapy. Betulinic acid (BA) is a bioactive phytocompound that has been reported to induce apoptosis in several types of cancers including melanomas; however, its effects on mitochondrial bioenergetics are less investigated. The present study performed in A375 human melanoma cells was aimed to characterize the effects of BA on mitochondrial bioenergetics and cellular behavior. BA demonstrated a dose-dependent inhibitory effect in both mitochondrial respiration and glycolysis in A375 melanoma cells and at sub-toxic concentrations (10 μM) induced mitochondrial dysfunction by eliciting a decrease in the mitochondrial membrane potential and changes in mitochondria morphology and localization. In addition, BA triggered a dose-dependent cytotoxic effect characterized by apoptotic features: morphological alterations (nuclear fragmentation, apoptotic bodies) and the upregulation of pro-apoptotic markers mRNA expression (Bax, Bad and Bak). BA represents a viable therapeutic option via a complex modulatory effect on mitochondrial metabolism that might be useful in advanced melanoma or as reliable strategy to counteract resistance to standard therapy.

Plant-Derived Anticancer Compounds as New Perspectives in Drug Discovery and Alternative Therapy

Despite the recent advances in the field of chemically synthetized pharmaceutical agents, nature remains the main supplier of bioactive molecules. The research of natural products is a valuable approach for the discovery and development of novel biologically active compounds possessing unique structures and mechanisms of action. Although their use belongs to the traditional treatment regimes, plant-derived compounds still cover a large portion of the current-day pharmaceutical agents. Their medical importance is well recognized in the field of oncology, especially as an alternative to the limitations of conventional chemotherapy (severe side effects and inefficacy due to the occurrence of multi-drug resistance). This review offers a comprehensive perspective of the first blockbuster chemotherapeutic agents of natural origin’s (e.g. taxol, vincristine, doxorubicin) mechanism of action using 3D representation. In addition is portrayed the step-by-step evolution from preclinical to clinical evaluation of the most recently studied natural compounds with potent antitumor activity (e.g. resveratrol, curcumin, betulinic acid, etc.) in terms of anticancer mechanisms of action and the possible indications as chemotherapeutic or chemopreventive agents and sensitizers. Finally, this review describes several efficient platforms for the encapsulation and targeted delivery of natural compounds in cancer treatment