SIRT6 and type 2 diabetes mellitus: Besides the biological relevance of monomeric anthocyanins, catechins, and LMWP, additional mechanistic in vitro and in vivo studies are necessary to fully define their specific roles and the occurrence of additive or synergistic effects as SIRT1 and SIRT6 activators in the prevention of endothelial damage due to type 2 diabetes.