College of Food Science, South China Agricultural University, Guangzhou 510642, China; LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
CICECO - Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal; LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Carbohydr Polym. 2021 Aug 15;266:118106. doi: 10.1016/j.carbpol.2021.118106. Epub 2021 Apr 24.
Longan (Dimocarpus longan Lour.) is a seasonal tropical fruit used by Chinese medicine in both fresh and dried pulp forms. Their polysaccharides have been reported to have biological activity. However, their composition and immune activity have not yet been disclosed. To fulfil this aim, hot water-soluble polysaccharides of fresh and dried longan pulp were fractionated according to their molecular weight by ultrafiltration (10, 50, 100 kDa cut off). The main polysaccharides recovered were 1,6-linked glucans branched at O-3 (4-8%), O-2 (1%), O-2,4 (0.1%), and O-3,4 (0.1%). The drying process promotes the solubility of the polysaccharides. These glucans from fresh and dried longan pulp have immunomodulatory activity, shown by in vitro phagocytosis, NO, TNF-α, and IL-6 macrophages production assays. They showed also to inhibit the inflammatory response induced by LPS. The immunological activity of these glucans seems to have different responses dependent on their molecular weight, related to the immune regulatory pathways.
桂圆（Dimocarpus longan Lour.）是一种季节性热带水果，在中国医学中既以新鲜果肉形式使用，也以干果肉形式使用。其多糖已被报道具有生物活性。然而，其组成和免疫活性尚未被披露。为了实现这一目标，根据分子量大小，采用超滤法（截留分子量为 10、50 和 100 kDa）对新鲜和干桂圆果肉的热水溶性多糖进行了分级。回收的主要多糖是 1,6-连接的葡聚糖，在 O-3（4-8%）、O-2（1%）、O-2,4（0.1%）和 O-3,4（0.1%）处支化。干燥过程促进了多糖的溶解度。这些来自新鲜和干桂圆果肉的葡聚糖具有免疫调节活性，表现在体外吞噬作用、NO、TNF-α 和 IL-6 巨噬细胞产生试验中。它们还能抑制 LPS 诱导的炎症反应。这些葡聚糖的免疫活性似乎因其分子量而异，与免疫调节途径有关。
