Zn(ferulate)-LSH Systems as Multifunctional Filters

Abstract

Excessive UV solar radiation exposure causes human health risks; therefore, the study of multifunctional filters is important to skin UV protective ability and also to other beneficial activities to the human organism, such as reduction of reactive oxygen species (ROS) responsible for cellular damages. Potential multifunctional filters were obtained by intercalating of ferulate anions into layered simple metal hydroxides (LSH) through anion exchange and precipitation at constant pH methods. Ultrasound treatment was used in order to investigate the structural changes in LSH-ferulate materials. Structural and spectroscopic analyses show the formation of layered materials composed by a mixture of LSH intercalated with ferulate anions, where carboxylate groups of ferulate species interact with LSH layers. UV-VIS absorption spectra and in vitro SPF measurements indicate that LSH-ferulate systems have UV shielding capacity, mainly UVB protection. The results of reactive species assays show the ability of layered compounds in capture DPPH•, ABTS•+, ROO•, and HOCl/OCl− reactive species. LSH-ferulate materials exhibit antioxidant activity and singular optical properties that enable their use as multifunctional filters.

A Sustainable Multistage Process for Immobilizing Bioactive Compounds on Layered Double Hydroxides

“…In the case of LDH_FA_1.1, and more prominently in LDH_FA_1.2, the (003) reflection comprises two overlapping signals with maxima at 5.1 and 3.9 • , corresponding to a d-value of 1.7 and 2.3 nm, respectively. By considering the dimensions of the ferulate anion obtained by semi-empirical calculations (1.8 × 7.1 × 9.4 Å), possibly the ferulate can arrange in the interlamellar space as both a monolayer and a bilayer [16,40,41]. The basal distance corresponding to the monolayer arrangement aligns with the 5.1 • signal while the bilayer arrangement leads to an increase in the interlamellar space consistent with the 3.9 • signal.…”

“…The XRD diffractograms of LDH-FA_1.1 and LDH-FA_1.2 samples (Figure 5) revealed a diffraction signal (003) at lower angles (with a maximum at 5.1 • ) compared to their precursor LDH-NO 3 (9.9 • ), indicating the intercalation of the anion between the lamellae [14,40]. Additionally, both LDH_FA_1.1 and LDH_FA_1.2 exhibited a signal at approximately 10.5 • attributed to the (006) reflection of the intercalated product, with less intense signals observed at higher angles, likely corresponding to higher order reflections.…”