Optimisation of ultrasound-assisted extraction and evaluation of anti-inflammatory and antioxidant activities of polysaccharides from <i>Livistona chinensis</i> fructus

<i>Livistona chinensis fructus</i>, a traditional medicinal fruit from southern China, is known for its ability to promote blood circulation, alleviate stagnation, and soften masses. It has been historically applied in chronic hepatitis treatment and shows emerging potential in cancer therapy. However, the key bioactive components remain unclear. This study aimed to optimise the ultrasound-assisted extraction of polysaccharides (LCP) from <i>L. chinensis</i> using Response Surface Methodology (RSM). Optimal extraction conditions—the liquid-to-solid ratio of 18:1 mL/g, extraction time of 2.2 h, and temperature of 88 °C—resulted in a 7.2% LCP yield with a low relative standard deviation (0.095%). <i>In vitro</i> assays using LPS-induced RAW 264.7 macrophages demonstrated that LCP significantly suppressed inflammatory markers (NO, IL-1β, TNF-α) and upregulated the anti-inflammatory cytokine IL-10. Moreover, LCP exhibited strong antioxidant activity, with IC₅₀ values of 0.474 and 1.963 mg/mL against ABTS and DPPH radicals, respectively. In H₂O₂-induced oxidative stress models, LCP protected RAW 264.7 cells and reduced reactive oxygen species (ROS) levels in a dose-dependent manner. These results highlight the therapeutic potential of LCP as a natural anti-inflammatory and antioxidant agent, providing a scientific basis for its future development in medicinal applications.