Browsing by Author "Tavares-Valente, Diana"
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- Biological potential and bioaccessibility of encapsulated curcumin into cetyltrimethylammonium bromide modified cellulose nanocrystalsPublication . Casanova, Francisca; Pereira, Carla F.; Ribeiro, Alessandra B.; Castro, Pedro M.; Freixo, Ricardo; Martins, Eva; Tavares-Valente, Diana; Fernandes, João C.; Pintado, Manuela E.; Ramos, Óscar L.Curcumin is a natural phenolic compound with important biological functions. Despite its demonstrated efficacy in vitro, curcumin biological activities in vivo are dependent on its bioaccessibility and bioavailability, which have been highlighted as a crucial challenge. Cetyltrimethylammonium bromide-modified cellulose nanocrystals (CNC-CTAB) have been shown to be effective in curcumin encapsulation, as they have the potential to enhance biological outcomes. This study evaluated the biological effects of curcumin encapsulated within CNC-CTAB structures, namely its antioxidant, anti-inflammatory and antimicrobial properties, as well as the release profile under digestion conditions and intestinal permeability. Encapsulated curcumin demonstrated antioxidant and anti-inflammatory properties, effectively reducing reactive oxygen species and cytokine production by intestinal cells. The delivery system exhibited antimicrobial properties against Campylobacter jejuni bacteria, further suggesting its potential in mitigating intestinal inflammation. The system showed the ability to protect curcumin from degradation and facilitate its interaction with the intestinal epithelium, highlighting the potential of CNC-CTAB as carrier to enhance curcumin intestinal biological functions.
- Breaking the virus: yeast glucans as an effective alternative to acyclovir in HSVI treatmentPublication . Tavares-Valente, Diana; Moreira, Helena; Sousa, Pedro; Amorim, Manuela; Conde, António; Pintado, Manuela; Fernandes, João; Azevedo-Silva, JoãoGlucans, structural polysaccharides in the yeast cell wall, are known for their biological and immunomodulatory capacities, helping in prevention and management of infections. Herpes simplex virus type 1 (HSVI) is a prevalent infection that causes great comorbidity and is challenging to treat due to the adverse effects of standard antiviral drugs like acyclovir. This study assessed the potential of yeast glucans extracted from two different origins − a steviol-glycoside producing strain and a wild-type strain- to circumvent HSVI infection, either in vitro and ex vivo. Treatment with glucans in keratinocytes and macrophages in vitro reduced cell infection similarly to acyclovir. However, unlike acyclovir, glucans demonstrated an immunostimulatory effect, increasing the production of IL-1β, TNF-α and IL-6. Additionally, both glucans were formulated with squalane for skin application. This formulation improved glucans penetration in the skin, restored skin structure and reduced the cytopathic effect of HSVI infection. In summary, this study highlights yeast glucans as a natural therapeutic alternative for HSVI treatment, offering an option with an excellent safety profile. Moreover, using glucans from industrial side-streams promotes a sustainable approach, contributing to the circular economy.
- Circular economyeast: saccharomyces cerevisiae as a sustainable source of glucans and its safety for skincare applicationPublication . Sousa, Pedro; Tavares-Valente, Diana; Pereira, Carla F.; Pinto-Ribeiro, Inês; Azevedo-Silva, João; Madureira, Raquel; Ramos, Óscar L.; Pintado, Manuela; Fernandes, João; Amorim, ManuelaGlucans, a polysaccharide naturally present in the yeast cell wall that can be obtained from side streams generated during the fermentation process, have gained increasing attention for their potential as a skin ingredient. Therefore, this study focused on the extraction method to isolate and purify water-insoluble glucans from two different Saccharomyces cerevisiae strains: an engineered strain obtained from spent yeast in an industrial fermentation process and a wild strain produced through lab-scale fermentation. Two water-insoluble extracts with a high glucose content (> 90 %) were achieved and further subjected to a chemical modification using carboxymethylation to improve their water solubility. All the glucans' extracts, water-insoluble and carboxymethylated, were structurally and chemically characterized, showing almost no differences between both yeast-type strains. To ensure their safety for skin application, a broad safety assessment was undertaken, and no cytotoxic effect, immunomodulatory capacity (IL-6 and IL-8 regulation), genotoxicity, skin sensitization, and impact on the skin microbiota were observed. These findings highlight the potential of glucans derived from spent yeast as a sustainable and safe ingredient for cosmetic and skincare formulations, contributing to the sustainability and circular economy.
- Exploring cannabidiol (CBD) and cannabigerol (CBG) safety profile and skincare potentialPublication . Luz-Veiga, Mariana; Mendes, Adélia; Tavares-Valente, Diana; Amorim, Manuela; Conde, António; Pintado, Manuela Estevez; Moreira, Helena R.; Azevedo-Silva, João; Fernandes, JoãoCannabinoids have long been known for their bioactive properties, with their topical application as anti-inflammatory compounds being at the forefront of research for the past decade. Concurrently, the cosmetic market is a fast-growing industry in constant need of new biomolecules. In this work, we studied the safety profile for topical applications of two cannabinoids: cannabidiol (CBD) and cannabigerol (CBG) and assessed their potential as skin care ingredients. The CBG used in this work resulted from bio-fermentation, and to the best of our knowledge, there are no extensive reports on its safety and usage as a cosmetic ingredient. Our results show that CBD and CBG do not exhibit cytotoxicity, mutagenicity, or skin sensitization. Moreover, we verified an absence of primary irritability, accumulated irritability, phototoxicity and photosensitization, supporting the claims of dermatologically tested, hypoallergenic and non-irritating. While these cannabinoids did not show significant anti-aging effects by altering the extracellular matrix components (both in vitro and ex vivo), they demonstrated promise as protective agents against inflammation caused by air pollution. Specifically, they reduced the levels of pro-inflammatory cytokines, making them valuable in combating environmental skin damage. Overall, our results validate the safety of topical use of cannabinoids, while paving the way for further research in the beauty and personal care market as soothing agents.
- Exploring yeast glucans for vaccine enhancement: sustainable strategies for overcoming adjuvant challenges in a SARS-CoV-2 modelPublication . Azevedo-Silva, João; Amorim, Manuela; Tavares-Valente, Diana; Sousa, Pedro; Mohamath, Randolph; Voigt, Emily A.; Guderian, Jeffrey A.; Kinsey, Robert; Viana, Sofia; Reis, Flávio; Pintado, Manuela E.; Paddon, Christopher J.; Fox, Christopher B.; Fernandes, João C.Vaccine adjuvants are important for enhancing vaccine efficacy, and although aluminium salts (Alum) are the most used, their limited ability to induce specific immune responses has spurred the search for new adjuvants. However, many adjuvants fail during product development due to manufacturability, supply, stability, or safety concerns. This work hypothesizes that protein-free yeast glucans can be used as vaccine adjuvants due to their known immunostimulatory activity and high abundancy. Thus, high molecular weight glucans with over 99% purity, comprising 64–70% β-glucans and 29–35% α-glucans, were extracted from a wild-type yeast and an engineered yeast to produce a steviol glycoside. These glucans underwent carboxymethylation to enhance solubility. Both water-dispersible and particulate glucans were evaluated as adjuvants, either alone or in combination with Alum or squalene stable emulsion (SE), for a SARS-CoV-2 vaccine. The study demonstrated that glucans triggered a robust immune response and enhanced the effects of Alum and SE when used in combination, both in vitro and in vivo. Water-dispersible glucans combined with Alum, and particulate glucans combined with SE, increased the production of specific antibodies against SARS-CoV-2 spike protein and enhanced serum neutralization titers against SARS-CoV-2 pseudovirus. Furthermore, the results indicated that larger molecular weight glucans from engineered yeast exhibited stronger immunogenic activity in comparison to wild-type yeast glucans. In conclusion, appropriately formulated glucans have the potential to be scalable, low-cost vaccine adjuvants, potentially overcoming the limitations of current adjuvants.
- Modified cellulose nanocrystals encapsulating cannabigerol: a step forward in controlling intestinal inflammatory disordersPublication . Casanova, Francisca; Pereira, Carla F.; Ribeiro, Alessandra B.; Castro, Pedro M.; Martins, Eva; Freixo, Ricardo; Tavares-Valente, Diana; Pimentel, Lígia L.; Fontes, Ana L.; Rodríguez-Alcalá, Luís M.; Fernandes, João C.; Pintado, Manuela E.; Ramos, Óscar L.Cannabigerol (CBG) from Cannabis sativa L. is known for its anti-inflammatory, antibacterial, and antioxidant properties, showing potential against intestinal inflammation. However, its lipophilic nature limits its absorption and stability. Researchers have explored cellulose nanocrystals (CNCs) to deliver lipophilic compounds and enhance their biological outcomes. This study investigated the capability of modified CNC with cetyltrimethylammonium bromide (CTAB) to effectively deliver CBG. The encapsulation process’s impact on cytotoxicity, biological activity, and controlled release during digestion was assessed. Results indicated that CNC-CTAB encapsulation significantly reduced CBG’s cytotoxicity on intestinal cells, allowing safer administration of higher doses. The antioxidant and anti-inflammatory properties of the encapsulated CBG were retained, resulting in a decrease in reactive oxygen species and cytokine levels in intestinal cells. Additionally, the system inhibited the growth of the intestinal pathogen Campylobacter jejuni. The study supports using CNC-CTAB as an efficient delivery system to enhance CBG’s potential against intestinal inflammation. Incorporating this system into food matrices could lead to novel functional foods for managing intestinal inflammation.
- Silica microparticles from sugarcane by-products as an encapsulation system for retinoids aimed at topical sustained releasePublication . Costa, Joana R.; Costa, Ana Helena; Azevedo-Silva, João; Tavares-Valente, Diana; Sousa, Sérgio C.; Neto, Tânia; Pintado, Manuela E.; Madureira, Ana RaquelThe encapsulation of retinol within silica microparticles has emerged as a promising opportunity in the realm of cosmetic and pharmaceutical formulations, driven by the need to reinforce the photoprotection and oxidation stability of retinol. This work examines the process of encapsulating retinol into silica microparticles. The association efficiency, microparticle size, molecular structure, morphology, oxidation, and release profile, as well as biocompatibility and skin sensitization, were evaluated. Results showed that 0.03% of retinol and 9% of emulsifier leads to an association efficiency higher than 99% and a particle size with an average of 5.2 µm. FTIR results indicate that there is an association of retinol with the silica microparticles, and some may be on the surface. Microscopy indicates that when association happens, there is less aggregation of the particles. Oxidation occurs in two different phases, the first related to the retinol on the surface and the second to the associated retinol. In addition, a burst release of up to 3 h (30% free retinol, 17% associated retinol) was observed, as well as a sustained release of 44% of retinol up to 24 h. Encapsulation allowed an increase in the minimal skin cytotoxic concentrations of retinol from 0.04 μg/mL to 1.25 mg/mL without skin sensitization. Overall, retinol is protected when associated with silica microparticles, being safe to use in cosmetics and dermatology.