Novel nanoparticles (NPs) were constructed with lysozyme (LY) and pectin (Ps) through self-assembly, which were used as a carrier to encapsulate epigallocatechin-3-gallate (EGCG). The binding of EGCG and LY is a static quenching process. Hydrogen bonds might play a major role in the formation of NPs, which has also been verified by a lower binding constant of EGCG with LY/Ps NPs. Meanwhile, EGCG could lead to conformational and microenvironmental changes of LY, resulting in more folding of LY secondary structures. In addition, attaching Ps to LY might inhibit LY aggregation induced by addition of free EGCG. At the LY/Ps mass ratio of 1:1, the constructed LY/Ps NPs had a high EGCG-loading capacity without a significant change in mean particle size, thus, our NPs could be used as an effective nanocarrier for loading EGCG. In vivo, compared with free EGCG, EGCG loaded onto LY/Ps NPs significantly increased Caenorhabditis elegans' (C. elegans) resistance to heat stress and oxidative injury and prolonged their lifespan. This study provides theoretical basis and reference for constructing nanoactive substance carriers so as to improve the resistance of organisms to heat stress and oxidative damage and to increase their survival rate and extend their lifespan under environment stresses.
Keywords: Caenorhabditis elegans; EGCG; lysozyme; nanoparticles; pectin; stress defense.