One-pot biocatalysis of potato rhamnogalacturonan and the role of its deacetylation in efficient inhibition of colon cancer cells and hydrogel mediated colon-targeted drug delivery

Deacetylation of potato rhamnogalacturonan (PRG) by rhamnogalacturonan acetyl esterase (CtPae12B) Ct Pae12B) was explored for enhanced hydrolysis of PRG by rhamnogalacturonan lyase (CtRGLf) Ct RGL f ) and the effects of deacetylated PRG were studied in enhancing inhibition of colon-cancer cells and formation of colon-targeting drug delivery material. Pre-treatment of PRG with Ct Pae12B resulted in increased relative activity of Ct RGL f . Ct Pae12B removed acetyl groups from both O-2 and O-3 positions of D-galactopyranosyluronic acid residues of PRG, resulting in 98 % deacetylation. PRG displayed 21.9 % degree of acetylation and 7.7 % degree of methylation. TLC and ESI-MS analysis of Ct RGL f hydrolysed PRG showed unsaturated RG di-saccharide as the smallest product, with m / z 322. Deacetylated PRG-oligosaccharides displayed higher, 50 % inhibition of colon-cancer HCT-116 cells (with shrunken and globular morphology) than 35 % inhibition by acetylated PRGoligosaccharides. FESEM and BET analysis of Ct Pae12B-treated PRG showed porous structure and significantly higher total surface area and pore volume than non-enzyme treated PRG. Higher drug entrapment efficiency and lower drug release rate of Ct Pae12B-treated PRG hydrogel (0.0033 min(-1) at pH 1.2 and 0.009 min(-1) at pH 7.4), than non-enzyme treated PRG hydrogel, (0.0057 min(-1) at pH 1.2 and 0.02 min(-1) at pH 7.4), showed it to be a potential biomaterial for sustainable colon-targeted drug delivery.