Purification Process and in Vitro Anti-inflammatory Activity of Total Polyphenols from Hedyotis Diffusa Willd.

OBJECTIVE To explore the optimal purification process condition of macroporous resin on the total polyphenolic compounds of Hedyotis diffusa, and to investigate its in vitro anti-inflammatory effect.

METHODS The total polyphenols in Hedyotis diffusa were extracted by ultrasound-assisted extraction, and the adsorption effect of different macroporous resins was investigated in static adsorption-desorption equilibrium kinetic experiments to screen the optimal purification process conditions, and the anti-inflammatory activity was evaluated by the inhibition of 5-lipoxygenase(5-LOX) and cyclooxygenase-2(COX-2) assays.

RESULTS The purification of total polyphenols from Hedyotis diffusa using HPD-826 macroporous resin was found to be most effective under the following conditions: sample concentration of 1.5 mg·mL⁻¹, pH of 5.0, sample volume of 90 mL, sample flow rate of 1.0 mL·min⁻¹, elution solution ethanol volume fraction of 70%, elution solution volume of 80 mL, and elution flow rate of 1.0 mL·min⁻¹. Under these conditions, the purity of total polyphenols from Hedyotis diffusa increased from (27.13±1.36)% to (63.08±0.83)%, representing a 1.32-fold improvement. The ethanolic extract of Hedyotis diffusa with a total polyphenol concentration of 20 mg·mL⁻¹ exhibited a (57.15±7.16)% inhibition rate against 5-LOX activity, while the ethanolic extract with a total polyphenol concentration of 3.2 mg·mL⁻¹ demonstrated an (83.49±2.48)% inhibition rate against COX-2 activity.

CONCLUSION The macroporous resin purification technology can enhance the purity of total polyphenols from Hedyotis diffusa. It exhibits inhibitory effects on inflammation-mediated 5-LOX and COX-2, with a more pronounced inhibitory effect on COX-2.