Xanthine oxidase inhibitory activity of northeastern North American plant remedies used for gout

Xanthine oxidase (xanthine: oxygen oxidoreductase EC 1.2.3.2) inhibitory ac tivity was assayed from 26 species belonging to 18 families traditionally u sed for the treatment of gout and related symptoms by Indigenous people of northeastern North America. The degree of inhibition was determined by meas uring the increase in absorbance at 295 nm associated with uric acid format ion. Eighty-eight percent of the plants were found to have inhibitory activ ity at 100 mu g/ml, with 20% having greater than 50% inhibition. Larix lari cina exhibited the highest activity with an inhibition of 86.33%. Of the sp ecies with the highest activity, Lineweaver-Burk plots showed that inhibiti on mode was of linear mixed-type. Inhibitory activity of the plants correla ted positively with their phenolic content (r = 0.52 P < 0.01) and tannin c ontent (r = 0.59 P < 0.001). (C) 1999 Published by Elsevier Science Ireland Ltd. All rights reserved.