[Modulatory effects of raw and honey-processed Astragali Radix fractions on intestinal microbiota, short-chain fatty acid metabolism and immune activity in rats with spleen deficiency].

This study aimed to investigate the effects of total saponins, total flavonoids, and total polysaccharides from raw and honey-processed Astragali Radix on intestinal microbiota, short-chain fatty acid metabolism, and immune activity in rats with spleen deficiency. A spleen deficiency model was established using a combination of irregular diet, bitter-cold purgative administration and excessive fatigue. High-throughput 16S rRNA sequencing was employed to analyze the modulatory effects of different fractions from raw and honey-processed Astragali Radix on the structural diversity of intestinal microbiota in spleen-deficient rats. Headspace gas chromatography-mass spectrometry was used to determine the modulatory effects of these fractions on the metabolism of short-chain fatty acids. ELISA was employed to assess the effects of raw and honey-processed Astragali Radix on specific and non-specific immune activities of spleen-deficient rats. The results demonstrated that the total flavonoids, total saponins, and total polysaccharides from raw and honey-processed Astragali Radix significantly restored the abundance of the harmful bacterial genus Helicobacter in the intestines of spleen-deficient rats. Moreover, except for the total polysaccharides from both raw and honey-processed Astragali Radix, all other treatment groups also significantly reduced the abundance of the harmful bacterial genus Sutterella(P<0.05). The fractions from raw and honey-processed Astragali Radix were able to restore the levels of various short-chain fatty acids in the colon of spleen-deficient rats. Notably, the total polysaccharides from honey-processed Astragali Radix significantly outperformed those from raw Astragali Radix in increasing acetic acid content(P<0.05). The total polysaccharides of both raw and honey-processed Astragali Radix significantly restored the levels of IL-4, IL-6, IL-10, IL-18, IgA, and IgG in the serum and colon, as well as the level of IL-2 in the serum of spleen-deficient rats(P<0.05 or P<0.01). The restorative effects of the processed product were superior to those of the raw product. In summary, the specific and non-specific immunomodulatory effects of the components from raw Astragali Radix increased after honey-processing, thereby potentiating its efficacy in ameliorating spleen deficiency. These findings may provide a scientific basis for elucidating the mechanism by which honey-processing enhances the qi-tonifying and middle-strengthening effects of Astragali Radix.