Innovative Bio-Based Organic UV-A and Blue Light Filters from Meldrum’s Acid

Abstract

Faced with the ban of some organic UV filters such as octinoxate or avobenzone, especially in Hawaii, it became essential to offer new alternatives that are both renewable and safe for humans and the environment. In this context, a class of bio-based molecules displaying interesting UV filter properties and great (photo)stability has been developed from Meldrum’s acid and bio-based and synthetic p-hydroxycinnamic acids, furans and pyrroles. Moreover, p-hydroxycinnamic acid-based Meldrum’s derivatives possess valuable secondary activities sought by the cosmetic industry such as antioxidant and anti-tyrosinase properties. The evaluation of the properties of mixture of judiciously chosen Meldrum’s acid derivatives highlighted the possibility to modulate secondary activity while maintaining excellent UV protection. Meldrum’s acid derivatives are not only competitive when benchmarked against organic filters currently on the market (i.e., avobenzone), but they also do not exhibit any endocrine disruption activity.

Sinapic Acid Esters: Octinoxate Substitutes Combining Suitable UV Protection and Antioxidant Activity

“…It has been observed that the presence of methoxy substituents (-OMe) on the aromatic ring significantly decreased the interaction of molecules with endocrine receptor [46], therefore, the use of a sinapic acid core that possesses two -OMe substituents should result in a lower risk of endocrine disruption. Moreover, previous studies in our laboratory proved the innocuousness of several sinapic acid derivatives towards endocrine receptors [47,48]. However, while the sinapic core seems favorable with regards to human health, the impact of the ester moiety on the latter, as well as the possible environmental toxicity of these compounds, should not be overlooked.…”

Towards developing novel and sustainable molecular light-to-heat converters

“…The barbiturics were synthesised using a green methodology based on the Knoevenagel condensation in water. The syntheses use no catalyst or organic solvent, thereby improving atom economy, 40,82 and were performed at room temperature, thereby minimising energy consumption. Further, the barbiturics precipitated readily from the reaction medium, enabling their recovery and purification simply by a classic filtration, without recourse to energy-and solvent-consuming, and waste-generating, silica gel chromatography.…”

“…(1) applied green chemistry principles to the well-established Knoevenagel and Knoevenagel-Doebner condensation reactions of cinnamates [38][39][40][41] to develop a synthetic route to barbiturics; 38,39,[41][42][43][44][45][46][47][48][49][50][51] (2) explored the photophysical properties of these barbiturics using steady-state and ultrafast transient absorption spectroscopies to gain insight into the light-to-heat generating pathways; (3) complemented these experiments with time-dependent density functional theory (TDDFT) and DFT/multireference configuration interaction (DFT/MRCI) calculations to describe these molecular relaxation pathways more fully; and (4) used in silico approaches to explore the potential toxicity of the barbiturics on humans. 52,53 Experimental and Computational Methods…”

Synthesis of Biobased Phloretin Analogues: An Access to Antioxidant and Anti-Tyrosinase Compounds for Cosmetic Applications

“…First, concerning phloretin, its loss of absorbance was 5.9% against 26.0% for octinoxate and only 0.6% for avobenzone. Peyrot et al mentioned in their study that the acceptable absorbance loss to match the commercial UV filters specifications should be less than 5% [ 43 ]. Phloretin’s result was very close to these specifications and revealed itself more photostable than octinoxate.…”

“…Tyrosinase inhibition activity was evaluated using the method used by Peyrot et al [ 43 ]. In a 96-well microplate, 60 µL of ammonium formate buffer (50 mM, pH 6.4) were mixed with 10 µL of inhibitor solution at different concentrations: 10,000, 5000, 1000, 500, 100, 50, 10, 5, 1 and 0.5 µM in DMSO.…”