Structural characteristics and immunomodulatory effects of polysaccharides extracted from plant seeds: A review

In the past few decades, plant polysaccharides obtained from the roots, stems, leaves, flowers, fruits or seeds of herbaceous, woody, shrub and liana plants have become important sources for developing valuable functional foods and immune adjuvant. Compared with other plant parts, the research on plant seed polysaccharides (PSPs) is more less, and many seed resources remain unexplored. The study of the active substances in seeds, especially polysaccharides, is an indispensable part of research. PSPs have attracted immense attention because of their relatively low-toxicity and various biological activities. The article reviews experimental studies regarding structural characteristics and immunomodulatory effects of polysaccharides which extracted from plant seeds, covering a period of over 20 years. Increasing evidence has suggested that PSPs can exert their active functions through immunomodulatory effects. This review aims to summarize the relationships among plant sources, structural characteristics and the immunomodulatory effects of PSPs, and thus provide theoretical support for the application of plant seeds, especially for the further application of PSPs as valuable food or as functional factors related to the immune response. •Plant seeds are a potential rich resource for obtaining polysaccharides.•The extraction and purification methods of various plant seed polysaccharides were analyzed and compared.•This review could provide theoretical support for the application of plant seed polysaccharides.•The relationship of structural characteristics and immunomodulatory effects of plant seed polysaccharides were discussed.