[Determination of eliminating ratio of Chinese traditional medicine for hydroxyl radical by fluorescent spectrophotometry].

Benzoic acid with weak fluorescence may react on .OH, and products with intense fluorescence are made. Extractives of Chinese traditional medicine may eliminate .OH in solution, and make amounts of the products to reduce. Then, increase level of fluorescence of products in solution will be lowered. Based on this principle, a new method is developed to determine eliminating ratio of Chinese traditional medicine for .OH. It is shown that productivity of .OH tends to saturation when H2O2 is shown more than 20 min by 280 nm UV light; .OH may react on benzoic acid completely when molar ratio of H2O2 and benzoic acid is 30:1; linear response range of products fluorescence is 2.2-80 mmol.L-1 with concentration of H2O2. IC50 of elimination .OH with magnoliae and eucommia are 1.025 and 515.3 mg.L-1 respectively. There are no remarkable difference between these results and that of spectrophotometry.