A Bioinspired Strategy Toward UV Absorption Enhancement of Melaninlike Polymers for Sun Protection

Due to the complexity of the structure within melanin and synthetic polymers(i.e.,polydopamine,PDA),it is a challenge to regulate the ultraviolet(UV)absorption.In nature,melanocytes can biosynthesize more pheomelanins than eumelanins via protein and gene overexpression for photoprotection when the UV irradiation is enhanced.During this biosynthetic pathway,L-cystine,transported by xCT gene,can be involved to form a new monomer structure incorporating a benzothiazole group,finally resulting in the formation of UV absorption-enhanced pheomelanin.Inspired by this,we have proposed a facile strategy to regulate the UV absorption of PDA by introducing the benzimidazole(BI)unit through the thiol-Michael addition reaction during the polymerization process.It was further found that the introduction of BI units not only significantly increased the content of chromophores and auxochromes,but also effectively restricted the red-shift of the absorption spectrum via interrupting the conjugated microstructure within PDA,both of which contribute to UV absorption enhancement.These UV absorption-enhanced PDA nanoparticles could be used to fabricate bio-inspired sunscreens for efficient sun protection.This work will provide a facile strategy to regulate UV absorption of melanin-like materials and open new horizons for the design and construction of bioinspired sunscreens.

A state of the science on influential factors related to sun protective behaviors to prevent skin cancer in adults

Skin cancer rates have risen over the past decades,making it imperative that adults understand the need for protection from sun exposure.Though some risk factors have been identified as predictive for skin cancers,there is a lack of synthesized information about factors that influence adults in their decisions to engage in sun protective behaviors.The purpose of this paper is to present the current state of the science on influential factors for sun protective behaviors in the general adult population.A rigorous literature search inclusive of a generally White,Caucasian,and non-Hispanic adult population was performed,and screening yielded 18 quantitative studies for inclusion in this review.Findings indicate that modifiable and non-modifiable factors are interdependent and play a role in sun protective behaviors.This study resulted in a proposed conceptual model for affecting behavioral change in sun protection including the following factors:personal characteristics,cognitive factors,family dynamics,and social/peer group influences.These factors are introduced to propose tailored nursing interventions that would change current sun protective behavior practice.Key implications for nursing research and practice focus on feasibility of annual skin cancer screening facilitated by advanced practice nurses,incorporating the identified influential factors to reduce skin cancer risk and unnecessary sun exposure.

The Phytochemical Profile and Photoprotective Potential of Bark and Leaves of Erythrina velutina Willd.—A Medicinal Species from the Caatinga Region of Brazil

The use of medicinal plants as therapeutic and economic resources has been on the rise in recent years. In Brazil, however, increasing doubt is being cast on the quality of these products, owing to the prevalence of adulteration and fraud. Solar radiation can cause serious damage to human skin, as a result, mostly, of ultraviolet light, which is a cause of skin cancer. Photoprotective substances are capable of absorbing, reflecting, or refracting ultraviolet radiation and thus protecting skin from exposure to sunlight. The present study aimed to characterize samples and examine the phytochemical profile and photoprotective potential of bark and leaves of Erythrina velutina Willd. The samples underwent five extraction methods using 80% ethanol. The phenolic content was measured using spectrophotometry. Antioxidant activity was examined using the DPPH and the photoprotective properties of the plant extracts were assessed using the method developed by Mansur. There was a quantitative difference in some groups of metabolites, with higher levels of tannin in the bark and of flavonoids in the leaves. The latter showed greater DPPH free radical scavenging capacity than the bark, although higher levels of SPF were obtained from the bark, with no statistically significant differences between methods. The results indicate that Erythrina velutina Willd. has potential as a photoprotector.

Study on the preparation and properties of sunscreen O/W/Si multiple emulsion

To solve the greasiness and irritation risks brought about by organic sun-screening agents in sunscreen emulsions,in this work,a sunscreen O/W/Si multiple emulsion was prepared by two-step emulsification method,in which the outer oil phase was silicone oil and the inner oil phase was solid lipid nanoparticles coated with organic sun-screening agent.Several influencing factors on the formation and stability of the emulsion were analyzed,including inorganic salts,the volume fraction of outer oil phase(silicone oil),and the dosage of W/O emulsifier.The in vitro sunscreen performance,water resistance and skin permeability of different types of sunscreen emulsions were further studied.The results showed that the sunscreen O/W/Si multiple emulsion containing 22.5%silicone oil,2.5%emulsifier and 0.2%NaCl had the best stability under the experimental conditions.The SPF value and water resistance of sunscreen O/W/Si multiple emulsion were slightly higher than those of sunscreen W/O emulsion,but significantly higher than those of sunscreen O/W emulsion.Compared with sunscreen W/O emulsion,the in vitro transdermal permeability of organic sun-screening agent in sunscreen O/W/Si multiple emulsion was reduced by approximately 60%,indicative of higher safety and good application prospect in sunscreen cosmetics.

Assessment of flavonoid-rich extracts from dark peels of Ficus carica L.fruits for cosmeceutical and antimicrobial applications

Background:Exploring natural sources to identify new active ingredients for cosmeceutical and pharmaceutical applications is of interest to many researchers.Methods:Flavonoid-rich extracts from dark Ficus carica peels were investigated in the present study.Extracts were prepared from the peels of four dark cultivars(Bakor Noir,Bouankik,Azenjer and Tazegaght)using acidified methanol.The antimicrobial activity of the extracts was evaluated by the agar well diffusion assay followed by the minimal inhibitory concentration determination using the microdilution method against Gram-positive and Gram-negative pathogenic bacteria and two fungi.Cosmeceutical properties were evaluated by measuring antioxidant activity,ultraviolet absorption characteristics and sun protection factor values.The antioxidant activity of the extracts was measured using aβ-carotene-linoleic acid system.The toxicity of the extracts was assessed using a brine shrimp lethality assay.Results:The extracts contained high amounts of phenolic compounds(3.85–8.63 g/100 g),mainly flavonoids(up to 5 g/100 g).Multiple antibacterial activities were recorded against Gram-positive and Gram-negative bacteria,with the best actions against Bacillus subtilis(minimal inhibitory concentration=156.25µg/mL),Staphylococcus aureus and Pseudomonas aeruginosa(minimal inhibitory concentration=312.5µg/mL),but no antifungal activity was recorded.Azenjer extract showed high inhibition of lipid oxidation evaluated by theβ-carotene bleaching assay with a half-maximal inhibitory concentration of 88.84µg/mL.All extracts showed absorption peaks in the ultraviolet range and Azenjer and Tazegaght extracts at 25 mg/mL presented sun protection factor values>15.The brine shrimp toxicity assay results revealed lethal concentration of 50%values greater than 2,000µg/mL,indicating the safety of the extracts.Conclusion:Therefore,Ficus carica peel extracts could be considered original ingredients with potential applications in the formulation of antibacterial drugs and skincare products.