Characterization and Quantification of Luteolin-Metal Complexes in Aqueous Extract of Lonicerae Japonicae Flos and Huangshan Wild Chrysanthemum

Figure 3

Effects of reaction time and volume on luteolin-metal complex formation. (a) Luteolin (0.1 mmol) mixed with 0.02 mmol anhydrous calcium chloride, anhydrous zinc chloride, magnesium chloride hexahydrate, iron chloride hexahydrate, or copper chloride dihydrate was allowed to proceed for 0.5, 1, 2, or 4 h under heat backflow at a temperature of 90°C. (b) The reaction in (a) was carried out in 20, 40, 80, or 160 mL distilled water at 90 for 2 h. After free ion salts were removed, the reactants were analyzed by HPLC as described in methods. The experiment was performed at least three times independently in triplicate.

(a)

(b)