Phenolic
acids have significant
biological and pharmacological properties and some have demonstrated remarkable ability to alter
sulfate conjugation. However, the modulatory effects of phenolic
acids on
phenol sulfotransferases (PSTs) in vivo have not been described. The present investigation evaluates the role of
phenolic acid on the expression of PSTs in male Sprague-Dawley rat liver. According to the results,
gentisic acid,
gallic acid and
p-coumaric acid in a dosage of 100 mg/kg of
body weight for 14 consecutive days significantly increased P-form PST (PST-P) activity as compared with that of the control rats (P<.05), whereas the activity of M-form PST (PST-M) in rats that received
gallic acid and
p-coumaric acid were also significantly (P<.05) higher than in the control rats.
Reverse transcriptase-polymerase chain reaction results indicated that the changes in both PST-P and PST-M
mRNA levels by phenolic
acids were similar to those noted in the
enzyme activity levels. The plasma obtained from
phenolic acid-administered rats had significantly (P<.05) increased
oxygen radical absorbance capacity (ORAC(ROO*) values than that from control rats. In a bioavailability study, following
oral administration of
gallic acid and
p-coumaric acid, the phenolic
acids were detected in the plasma, and the Cmax values after 2.0-h administration were 665+/-23 and 550+/-33 nmol/L, respectively. There was a significant correlation between the activity of both forms of PSTs and the
antioxidant capacity of ORAC(ROO*) value by phenolic
acids (r=.74, P<.05 and r=.77, P<.05). These data suggest that phenolic
acids might alter
sulfate conjugation and
antioxidant capacity in living systems.