XDH and gout: In another study, we found that 3,4-dicaffeoylquinic acid (compound 31, IC50: 0.32 mmol/L), 4,5-dicaffeoylquinic acid (compound 32, IC50: 0.26 mmol/L), and 3,5-dicaffeoylquinic acid (compound 33, IC50: 0.21 mmol/L) exhibited weak xanthine oxidase inhibitory activity (Positive control: allopurinol, IC50: 0.01 mmol/L) (Chen et al., 2014), partially explaining the phytochemistry of anti-gout activity.