Guo Yue, Cheng Yanan, Zheng Bing, Xie Jianhua, Chen Yi, Lin Huasi, Liu Hui, Hu Xiaobo, Yu Qiang
State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, 235 Nanjing East Road, Nanchang 330047, China.
State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, 235 Nanjing East Road, Nanchang 330047, China.
Carbohydr Polym. 2025 Dec 1;369:124337. doi: 10.1016/j.carbpol.2025.124337. Epub 2025 Sep 2.
Gardenia jasminoides Ellis is an important medicinal and edible resource. However, the structure-activity relationships underlying the immunomodulatory activity of its polysaccharides remain incompletely understood. Herein, we aimed to characterize the structure of a novel pectin from Gardenia fruit and clarify its immunomodulatory mechanism. A homogeneous polysaccharide, GJP70-0.2 (M = 54.5 kDa), was isolated and purified from gardenia fruit. Structural analysis confirmed that it was a pectic polysaccharide characterized by a notably homogalacturonan (HG)-dominant architecture with minor rhamnogalacturonan-I (RG-I) domains. The main chain structure contains α-D-GalpA-(1→[4)-α-GalpA-6R-(1]→[3,4)-α-GalpA-(1]→[2,4)-α-Rhap-(1→4)-α-GalpA(1→], and the RG-I region harbors arabinan and type II arabinogalactan side chains. In vitro assays showed that GJP70-0.2 significantly enhanced RAW264.7 macrophage proliferation and phagocytic activity, and induced M1 polarization, as evidenced by increased nitric oxide (NO) and reactive oxygen species (ROS) secretion, as well as upregulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Mechanistically, GJP70-0.2 promoted M1 polarization by activating the NF-κB, JAK/STAT, and MAPK signaling pathways. Thus, the HG domain-dominant gardenia pectin polysaccharides exhibit potent immunomodulatory activities, supporting the potential of gardenia pectin polysaccharides as natural immunomodulators.
栀子是一种重要的药食两用资源。然而，其多糖免疫调节活性的构效关系仍未完全明确。在此，我们旨在表征一种来自栀子果实的新型果胶的结构，并阐明其免疫调节机制。从栀子果实中分离纯化得到一种均一多糖，GJP70 - 0.2（分子量 = 54.5 kDa）。结构分析证实它是一种果胶多糖，其特征是具有明显以同型半乳糖醛酸聚糖（HG）为主的结构，带有少量鼠李糖半乳糖醛酸聚糖 - I（RG - I）结构域。主链结构包含α - D - 半乳糖醛酸 - (1→[4)-α - 半乳糖醛酸 - 6R - (1]→[3,4)-α - 半乳糖醛酸 - (1]→[2,4)-α - 鼠李糖 - (1→4)-α - 半乳糖醛酸(1→]，且RG - I区域含有阿拉伯聚糖和II型阿拉伯半乳聚糖侧链。体外实验表明，GJP70 - 0.2显著增强RAW264.7巨噬细胞的增殖和吞噬活性，并诱导M1极化，这通过一氧化氮（NO）和活性氧（ROS）分泌增加以及诱导型一氧化氮合酶（iNOS）和环氧化酶 - 2（COX - 2）表达上调得以证明。机制上，GJP70 - 0.2通过激活NF - κB、JAK/STAT和MAPK信号通路促进M1极化。因此，以HG结构域为主的栀子果胶多糖具有强大的免疫调节活性，支持了栀子果胶多糖作为天然免疫调节剂的潜力。
