Silybin interacting with Cu4, Ag4 and Au4 clusters: Do these constitute antioxidant materials?

We analyze the free radical scavenger capacity of silybin-metal clusters systems by applying Density Functional Theory (DFT) calculations, following two well-known antioxidant mechanisms: the radical adduct formation (RAF) and the hydrogen atom transfer (HAT). As apparent in this investigation, the presence of tetramer clusters increases the antioxidant capacity of silybin and de-protonated silybin. In order to assess further antiradical processes, we also investigated the single electron transfer (SET) process (for the most stable structures derived from RAF and HAT mechanisms). From this study, we concluded that the presence of Cu-4, Ag-4 and Au-4 clusters enhances the free radical scavenging properties of silybin and de-protonated silybin. These metal-organic systems may serve as effective antioxidant materials. These results may provide encouraging guidance for those involved in these experiments and hold promise for future applications. (C) 2017 Elsevier B.V. All rights reserved.