Cadmium inhibits hSMUG1-mediated uracil excision: quantitative analysis and mitigation by <i>Ganoderma lucidum</i> extracts

= 4.6 μM), with near-complete inhibition at concentrations ≥25 μM. Notably, five Ganoderma lucidum extracts derived from different strains and extraction methods restored hSMUG1 activity (16.4-21.6%) under cadmium stress. ICP mass spectrometry revealed that these extracts reduced cadmium ion levels by 40-73%, suggesting metal chelation as a contributing mechanism. Together, our findings uncover a previously unrecognised mechanism by which cadmium compromises base excision repair and establishes a robust framework for evaluating environmental metal toxicity and its modulation at single-nucleotide resolution.