OBJECTIVE To optimize the extraction process of Kai-Xin-San polysaccharides(KXS-P) by hot water extraction, and to systematically evaluate its in vitro antioxidant and anti-inflammatory activities.

METHODS On the basis of single factor experiments, response surface methodology was used to optimize the extraction process with the material liquid ratio, extraction time and extraction temperature as influencing factors, and the polysaccharide yield as evaluation indicators. The antioxidant activity of polysaccharides was evaluated according to the clearance rate on DPPH radicals, ABTS⁺ radicals, hydroxyl radicals, and superoxide anion radicals. The in vitro cellular inflammation model was induced by lipopolysaccharide, and different concentrations of KXS-P were administered for intervention. The content of NO in the cell supernatant was detected using the Griess method, while the levels of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), and IL-6 were measured using the ELISA method.

RESULTS The optimal extraction conditions of KXS-P were as follows: material liquid ratio of 1∶20(g·mL⁻¹); extraction time of 100 min; extraction temperature of 62 ℃. The polysaccharide yield was (5.734±0.106)% under the optimal conditions. KXS-P had strong antioxidant activity with IC₅₀ values of 0.581, 0.212, 3.23, 1.33 mg·mL⁻¹ for DPPH, ABTS⁺, hydroxyl, and superoxide anion radicals, respectively. The results from cellular test showed that KXS-P could inhibit TNF-α, NO, IL-1β, and IL-6 in macrophages(P<0.05 or P<0.01) and the inhibition effect was dose-dependent.

CONCLUSION The optimized extraction process of KXS-P is stable and feasible. KXS-P have strong antioxidant activity and significant anti-inflammatory effects in vitro.