*4.4. G.K. Peptide*−*Ribose Assay*

This test was used to evaluate the ability of flavonoids to inhibit the crosslinking of G.K. peptides (last glycation products) in the presence of ribose, using the method described by Rahbar et al. [23]. The G.K. peptide (80 mg/mL) was incubated with 0.8 M ribose under sterile conditions in 0.5 M sodium phosphate buffer (pH 7.4) at 37 ◦C for 24 h. The adlay samples or phenolic acids were added at final concentrations of 125 μg/mL and 250 μg/mL, respectively. At the end of the incubation period, samples were analyzed for specific fluorescence (excitation, 340 nm; emission, 420 nm). The % inhibition by different concentrations of inhibitor was calculated as described above.

### *4.5. HPLC Analysis*

The HPLC analysis method according to a previous report [22], with a slight modification, was used and carried out on an UltiMate 3000 pump equipped with an autosampler column compartment system and a variable wavelength detector (DIONEX, manufacturer, Sunnyvale, CA, USA). A 4.6 mmØ × 250 mm (5 μM) reverse-phase C18 column was used (HiQ sil C18HS). Gradient elution was performed with 2% acetic acid(aq) (*v*/*v*, solvent A) and 0.5% acetic acid(aq)/acetonitrile (1:1, *v*/*v*, solvent B) at a constant flow rate of 1 mL/min. The initial condition was at 5% B, and the eluent was as follow: 0–10 min B increased from 5 to 10%, 10–40 min B increased from 10 to 40% and 40–55 min B increased from 40 to 55%. The waste was washed by increasing B from 55 to 100% within 10 min, and the eluent was adjusted to the initial condition (5% B) within 15 min. The absorbance at 280 nm was recorded. Phenolic standards, dissolved in DMSO, were analyzed, and peak areas of serial diluted standards were calculated for calibration curves. ATE-BuOH was analyzed using the HPLC system, and the contents of phenolic acids were compared with the retention times and calibration curves.

#### *4.6. Statistics*

All the experiments were performed in triplicate, and the values are expressed as the mean ± SD. Statistical analysis was performed via one-way analysis of variance (ANOVA), and multiple comparisons were performed utilizing Duncan's multiple range test. All statistical analyses were performed using the computer software SPSS 12.0. *p* < 0.05 was considered statistically significant.
