Rosmarinic Acid Multifunctional Sunscreen: Comet Assay and In Vivo Establishment of Cutaneous Attributes

Abstract

The skin acts as a protective barrier, guarding the body against microorganisms, chemicals, and several environmental factors. Accordingly, this all-important organ must be kept healthy to maintain its optimal functionality. One approach to maintain skin health is the application of multifunction bioactive sunscreens containing antioxidant molecule(s). Rosmarinic acid (RA), a phenolic compound, is known for its antioxidant activity. Herein, the safety and efficacy of a multifunction prototype sunscreen were investigated, aiming to evaluate the performance of this polyphenol with two known and widely used UV filters (bemotrizinol and octyl p-methoxycinnamate). Samples protected the DNA fragmentation compared to UV control, by the comet assay, and showed good skin compatibility in subjects. Formulations F1 and F3 were able to increase skin hydration, and, possibly, the RA interfered with this attribute. An increase in transepidermal water loss was observed for formulations F1, F2, and F4, which may be related to the vehicle, containing the RA or not. No decreases were observed in the inflammatory reaction caused by the ethyl nicotinate with any of the samples. As a perspective, we suggest trials with a greater number of subjects or protocol modifications. Altering the vehicle qualitative and quantitative composition is also a pertinent perspective.

HPLC‐TBARS‐EVSC (high‐performance liquid chromatography–thiobarbituric acid reactive substances–ex vivo stratum corneum) protocol: Selection of the subjects and approach to present the results

“…This hindrance can be minimized if the data are analysed using each subject as its own control, that is by examining putative differences in the ratios of the results obtained in the treated versus the control site. Several works conducted by our group have employed this strategy with satisfactory results, particularly taking into account that the panels of volunteers were relatively small (between 12 and 15 subjects) [8, 9, 16–20]. This study can also be considered as a corroboration of the advantages of using this approach, since the subtle differences between the two sexes were observed in the AUC ratios and not in the mean AUC.…”

“…Even though the skin has defence mechanisms against the oxidative stress, like enzymes and antioxidant molecules, being the stratum corneum the frontline of protection against the environment, the potential for an unfavourable unbalanced rate of oxidative reactions on this layer is significant. According to Alonso and coworkers, the lipoperoxidation of the skin results as a photo-oxidative injury that is amplified by the UV radiation, being the degradation of lipids and proteins an immediate consequence [7,8].…”

Protective Mechanisms of Polyphenol-Enriched Blueberry Preparation in Preventing Inflammation in the Skin against UVB-Induced Damage in an Animal Model

“…The topical application of RA emulsion further elucidated its anti-inflammatory efficacy by reducing TNF-α levels [53,56,58]. Evaluation of RA as a photoprotective adjuvant ingredient yielded successful results, manifesting an elevation in a sunscreen system's in vivo sun protection factor (SPF) [59,60].…”

Synergistic Differential DNA Demethylation Activity of Danshensu (Salvia miltiorrhiza) Associated with Different Probiotics in Nonalcoholic Fatty Liver Disease

“…Danshensu, ascorbic acid, and trolox exhibited dose-dependent effective antioxidant activity (Figure 2C). The result indicated the ability of DSS to scavenge excess radicals [54].…”