Comparison of Physicochemical and Immunomodulatory Properties of Polysaccharides from Fresh and Dried Longan Pulp Products
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Longan is a popular fruit and is widely distributed throughout the subtropical area. The dried pulp of longan has been used in traditional Chinese medicine and is made up of polysaccharides as one of the main bioactive ingredients. The nutritional difference between fresh and dried longan pulp products was investigated using analytical methods and the physicochemical properties and immunomodulatory activity of polysaccharides were evaluated. Gas chromatography-mass spectrometry (GC-MS), ion exchange chromatography, gel filtration chromatography, viscometry, ultraviolet (UV) spectroscopy, and infrared (IR) spectroscopy were performed. The results showed that the longan polysaccharides from fresh and dried fruits (i.e., LPF and LPD, respectively) were polysaccharide-protein complexes, but significant differences were found in their binding protein contents, neutral/acid polysaccharide ratios, monosaccharide compositions, molecular weight distributions, and intrinsic viscosities. Cellular in vitro tests confirmed LPD strongly stimulated lymphocyte proliferation and macrophage phagocytosis compared to LPF in the dose range of 50~400 μg/mL. Both polysaccharides significantly stimulated ConA-induced lymphocyte proliferation and nitric oxide production from macrophages (P < 0.05), but had a weak effect on lipopolysaccharide (LPS)-induced lymphocyte proliferation. The drying process of longan pulp may enhance the in vitro immunomodulatory activity of water-soluble polysaccharides by changing their physicochemical characteristics.
