Rats were treated with GSPE at 250 mg/Kg BW/day, 25 mg/Kg BW/day, or vehicle (control) for 11 days, and animals (n=4 per group) were sacrificed 6 hours after the last dose of GSPE/vehicle treatment. A) Detection of phenolic acids in perfused brain specimens from vehicle-treated control and GSPE treated groups. Data are displayed as mean ± SEM; * p<0.05, GSPE-treated compared to vehicle-treated control animals. 3-HBA and 3-HPP data are presented in bold to highlight significantly elevated contents for these two phenolic acids in brain specimen in response to GSPE treatment. Dark arrows indicate increased fold-change in GSPE-treated vs. vehicle-treated control brain specimens. B) Dose-responsive accumulation of 3-HBA and 3-HPP in brain specimens from animals treated with a daily dose of 250 or 25 mg/Kg BW/day GSPE. Bar graphs present mean ± SEM; * p<0.05, GSPE-treated compared to vehicle-treated control animals. C) Molecular structure of 3-HBA and 3-HPP. D) Representative HPLC resolution/detection of 3-HBA and 3-HPP from molecular standards (top spectrogram) and a brain specimen (bottom spectrogram). (Inset: MS-MS analysis of 3-HBA and 3-HPP from brain specimens following HPLC resolution).