2.6. β-hexosaminidase (β-hex) and His assay

RBL-2H3 and P815 cells were seeded in 24-well plates at 1 × 10⁵ cells/mL. C48/80 at 15 μg/mL (positive control) or different concentrations of 5-HMF (0.1 IC₅₀ and IC₅₀) were then administered to cells. After cell stimulation for 1 h, supernatants were collected for β-Hex and His assay, which were performed according to previous methods [20,21]. β-Hex and His release rates were calculated as percentages, when compared to the lysed group: i.e., release ratio (%) = (T—B)/(ZB) × 100 —%, where T, B and Z represented the OD of cells treated with drugs, cells without drugs, and cells lysed by 1% Triton X-100 (Sigma, MO, USA), respectively.