Differential effects of enzymatically modified Ougan (Citrus Suavissima Hort. ex Tanaka) peel pectins extracted with different methods on inhibiting the proliferation of Hela cells

Previous studies have shown that modified citrus pectin (MCP) is an anti-tumor material of food grade. In this study, two enzymatically modified Ougan (Citrus Suavissima Hort. ex Tanaka) peel pectins (EMP1 and EMP2, the ones extracted by alkali and enzymatic methods) were used to investigate their differential effects on viability and physiology of Hela cells. The results showed that EMP1 and EMP2 had 88.00 % and 81.01 % galacturonic acid, 21.31 % and 20.25 % esterification degree, 10,417 g/mol and 6416 g/mol molecular weight (Mw), 82.86 % and 50.62 % RG-I, and 8.91 % and 15.70 % HG, respectively. EMP2 had higher intensities of absorption peaks than EMP1. They were irregularly shaped, with more holes on EMP1 but more wrinkles on EMP2. Both could inhibit the growth, proliferation, migration, and invasion of HeLa cells in a concentration-dependent manner, with better efficiency in EMP2. Meanwhile, EMP2 was more efficient than EMP1 in blocking the cell cycle in S phase, resulting in apoptosis. In conclusion, the variations caused by extraction resulted in differences in anti-tumor activity of MCP and EMP2 with lower Mw and higher HG exhibited better anti-tumor effects. This study would provide an experimental basis and reference for the research and development of anti-tumor supplements from citrus pectin.