Sulfuric acid

Serum IgG and mucosal secretory IgA (sIgA) concentrations were measured using ELISA. Before testing, the samples were briefly diluted with PBS. Microplates containing 100 µL of diluted samples and 5 µg/well of H. pylori lysates were coated overnight at 4 °C. HRP-conjugated goat anti-mouse IgG (31,430, Thermo Fisher) and sIgA (ab97235, Abcam) were used after the plate had been cleaned with PBST. Tetramethylbenzidine (Solarbio, China) was used to view the plates after washing for 15 min in complete darkness. Finally, a solution of 2 M sulfuric acid (Solarbio, China) was used to terminate the process. A microplate reader was used to measure the absorbance at 450 nm.

Hemerocallis citrina Borani was obtained from Qingyang, Gansu, China. Standards of glucose, mannose, fucose, rhamnose, xylose, galactose, arabinose, glucuronic acid, ribose, and galacturonic acid were purchased from Shanghai Yuanye Biotechnology (Shanghai, China). Absolute ethanol was purchased from Fuyu Fine Chemical (Tianjin, China). Trifluoroacetic acid, methanol, sodium hydroxide, hydrochloric acid, carbazole, 1-phenyl-3-methyl-5-pyrazolone, 3,5-dinitrosalicylic acid, sulfuric acid, Coomash bright blue, chloroform, potassium bromide, sodium azide, sodium acetate, anthranone, and other reagents were purchased from Solarbio Biotechnology (Beijing, China). ABTS and FRAP assay kits were purchased from Suzhou Keming Biotechnology (Suzhou, China). Distilled water was used in these experiments.