Integrated EWM-RSM optimization of wine-steaming enhances the anti-inflammatory activity of Dendrobium huoshanense polysaccharides

Background Dendrobium huoshanense is a valuable medicinal herb in Traditional Chinese Medicine renowned for its polysaccharides which are considered a core pharmacological component, particularly for their anti-inflammatory properties. The herb is commonly subjected to wine-steaming processing to enhance its efficacy, yet the scientific rationale behind this traditional method remains insufficiently explored. Methods This study systematically optimized the wine-steaming processing parameters for D. huoshanense and comparatively evaluated the anti-inflammatory activities of its polysaccharides before and after processing. The physicochemical properties of the polysaccharides before and after wine steaming were characterized by scanning electron microscopy (SEM), size exclusion chromatography coupled with multi-angle light scattering and refractive index detection (SEC-MALS-RI), and high-performance liquid chromatography The anti-inflammatory effects were assessed using lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Key evaluations included the measurement of nitric oxide (NO) production and the analysis of mRNA expression levels of pro-inflammatory cytokines, namely TNF-α, IL-1β, IL-6, IL-10, iNOS, and COX-2. Results The optimal wine-steaming conditions were determined as follows: moistening with 38% yellow rice wine for 7.5 h followed by steaming for 5 h. Following processing, the polysaccharide yield slightly decreased from 27.0% ± 0.5% in the raw sample to 26.0% ± 0.4%. a significant reduction in molecular weight, and altered monosaccharide composition with a decreased mannose-to-glucose ratio. In vitro , the wine-steamed polysaccharides exhibited stronger anti-inflammatory activity than those from the raw herb, with the most pronounced effect observed at 200 μg/mL, as reflected by greater inhibition of NO production and stronger downregulation of TNF-α, IL-1β, IL-6, IL-10, iNOS, and COX-2 mRNA expression. Conclusion Wine-steaming processing significantly enhances the anti-inflammatory activity of D. huoshanense polysaccharides. These findings provide modern pharmacological evidence supporting the traditional processing method and offer a scientific basis for the standardized processing of this medicinal herb and the development of its polysaccharide-based active ingredients.