Catalytic hydrogenolysis of larix bark proanthocyanidins in ionic liquids produces UV blockers with potential for use in cosmetics

Abstract

Oligomeric proanthocyanidins with excellent UV resistance were prepared by hydrogenolysis in ionic liquids.

Oligomeric Proanthocyanidins: An Updated Review of Their Natural Sources, Synthesis, and Potentials

“…Although some proanthocyanidins including OPCs, PPCs, and their derivatives displayed similar biological potentials, such as antioxidant, anti-inflammatory, anti-aging, anti-bacterial, and antineoplastic activities [1], OPCs tend to have stronger antioxidant enzyme activity than PPCs, and can also pass through cell membranes more easily, as well as showing higher bio-accessibility rates compared with those of PPCs [23]. OPCs also tend to have greater free-radical scavenging capacities, and the ultraviolet (UV) transmittance of OPC-containing lotions and sunscreens, is higher than that of PPC-containing products [24]. Similarly, some research showed grape seed extracts containing more OPCs exhibited higher antioxidant capacities than cocoa extracts [25], and OPCs attenuated oxidative stress damage by directly scavenging reactive oxygen species (ROS), improving cellular endogenous antioxidant mechanisms, or regulating intracellular oxidation-related signaling pathways [26].…”

Depolymerisation–hydrogenation of condensed tannins as a strategy for generating flavan-3-ol monomers

“…Earlier work has already demonstrated the reductive cleavage of the interflavonoid bond in dimers using sodium cyanoborohydride in trifluoroacetic acid. 29 Also catalysed hydrogenolysis has been studied as a means of condensed tannin depolymerisation, 30–35 but detailed analysis and quantification of the reaction products has remained scarce. Most closely related but different from the work here, hydrogenolysis has also been used in synthetic chemistry for the removal of protecting benzyl groups from benzylated flavonoid molecules.…”

“…A general procyanidin structure is shown on the left, with the numbering indicated on one of its monomers. depolymerisation, [30][31][32][33][34][35] but detailed analysis and quantification of the reaction products has remained scarce. Most closely related but different from the work here, hydrogenolysis has also been used in synthetic chemistry for the removal of protecting benzyl groups from benzylated flavonoid molecules.…”

Mechanistic origins of accelerated hydrogenation of mixed alkylaromatics by synchronised adsorption over Rh/SiO2

“…Reactions with mixtures involve lower-value chemicals such as oil cracking or its renewable counterpart of bio-oil upgrading 1 as well as higher-value chemicals such as natural products in food and cosmetics. 2,3 Liquid phase reaction is common for the latter case. There are many unknowns in the interactions between the constituents in mixtures.…”