Abstract: Total triterpenoids was extracted from Scrophularia ningponesis Hemsl. with ethanol and ultrasonic-assisted. The influence factors such as material-to-liquid ratio(g:mL), ethanol volume fraction, ultrasonic extracting time and temperature were investigated based on single factor and orthogonal test. The total triterpenoids extract was purified by macro-porous resin and analyzed with oleanic acid. Research on hydroxyl radicals scavenging of purified total triterpenoids extracts was carried out. The antioxidation to oils and fats of purified total triterpenoids extracts were evaluated and compared with gallic acid and Vc. The results showed that the optimal extracting conditions were obtained as follows: 70% ethanol, 1:30(g:mL) material-to-liquid ratio, 40 min ultrasonic extracting time at 250 W and 70 ℃,twice extraction. Under above conditions, the extracts yield was 2.56% and the content of oleanic acid in purified total triterpenoids extracts was 88.50%. The purified total triterpenoids extracts exhibited excellent ability to remove ·OH and the oleanic acid concentration of IC₅₀ to ·OH was 12 mg/L. When antioxidation test was carried out at the condition of being kept in oven at 40 ℃ for 360 min, the protection rate was 20.5% to oil and 29.0% to fat,respectively. The antioxidating effect of purified total triterpenoids extracts was better than that of gallic acid and Vc to oils and almost the same as gallic acid and Vc to fats, respectively.

Key words: Scrophularia ningponesis Hemsl., total triterpenoids extracts, hydroxyl radicals, oils and fats, antioxidation biological activity