Structural features and immunomodulatory activities of polysaccharides of longan pulp

► Polysaccharides from longan pulp (Dimocarpus longan Lour. cv. Chu-liang) have been first fractionated. ► Their structural features and immunomodulatory activities have been characterized. ► The main immunomodulatory fractions of longan polysaccharides have been figured out ► The potential structure-function relationships of longan polysaccharides have been indicated. ► Our results support the medicinal application of dried longan pulp or longan polysaccharide.