Structural characteristics and biological activity of a water-soluble polysaccharide HDCP-2 from Camellia sinensis

Large-leaf Yellow tea (LYT) is a traditional beverage from Camellia Sinensis (L.) O. Kuntze in China and has unusual health-regulating functions. This investigation explored the structural characteristics of a polysaccharide extracted from LYT, which possesses anti-inflammatory activity. The polysaccharide HDCP-2, obtained through ethanol fractional precipitation and then DEAE-52 anion exchange column, followed by DPPH radical scavenging screening, exhibited a yield of 0.19 %. The HPGPC method indicated that the molecular weight of HDCP-2 is approximately 2.9 × 10⁴ Da. Analysis of the monosaccharide composition revealed that HDCP-2 consisted of mannose, glucose, xylose, and galacturonic acid, and their molar ratio is approximately 0.4:0.5:1.2:0.7. The structure motif of HDCP-2 was probed carefully through methylation analysis, FT-IR, and NMR analysis, which identified the presence of β-d-Xylp(1→, →2, 4)-β-d-Xylp(1→, →3)-β-d-Manp(1→, α-d-Glcp(1→ and →2, 4)-α-d-GalAp(1→ linkages. A CCK-8 kit assay was employed to evaluate the anti-inflammatory action of HDCP-2. These results demonstrated that HDCP-2 could inhibit the migration and proliferation of the MH7A cells and reduce NO production in an inflammatory model induced by TNF-α. The abundant presence of xylose accounted for 39 % of the LYT polysaccharide structure, and its distinctive linking mode (→2, 4)-β-d-Xylp(1→) appears to be the primary contributing factor to its anti-inflammatory effect.