Purification and composition of heartwood pigment of Pterocarpus macrocarpus

  Objective  In order to provide scientific basis for forming mechanism of Pterocarpus macrocarpus heartwood, we investigated the purification process of heartwood pigment and component identification.

  Method  The pigment of Pterocarpus macrocarpus heartwood was extracted by 7 solvents. The wavelength was measured to established a standard curves of the heartwood pigment concentration. In the purification process of the heartwood pigment, absorption efficiency, absorption concentration, desorption efficiency and desorption concentration of 10 kinds of macroporous resins were measured to determine the resin with the best absorption effect. In the process of dynamic absorption and desorption, the mass concentration of pigment was used as an indicator to explore the influence of different factors on DA-201 macroporous resin, and then determine the best absorption process. UPLC-Q-EXCTIVE-MS was used to separate and identify the components of purified pigment.

  Result  Ethanol was selected as the extraction solvent, and the chromatic aberration of solutions was 55.15. The 486 nm was used as the measurement wavelength to establish a standard curve. The optimum absorption conditions of DA-201 were as follows: static absorption concentration was 10.07 g/L, absorption rate was 80.19%. The optimum desorption conditions of DA-201 were as follows: static desorption concentration was 7.06 g/L, desorption rate was 70.07%. In the static absorption process of DA-201 macroporous resin, the optimum conditions were: pH value was 4, eluent ethanol concentration was 100%. In the dynamic absorption process of DA-201 macroporous resin, the optimal absorption conditions for pigment were: the absorption flow rate was 2.0 mL/min, the mass concentration of the sample solution was 2 g/L. The optimum conditions of desorption effect were: the elution flow rate was 1 mL/min and the eluent volume was 100 mL. UPLC-Q-EXCTIVE-MS was used to separate and identify 10 flavonoids and alcohol compounds from the purified pigment, which were orientin, vitexin, genistein, resveratrol, chrysin, glycitein, isoliquiritin, nocarone, formononetin, ketoprofen.

  Conclusion  DA-201 macroporous resin can purify the pigment of Pterocarpus macrocarpus heartwood effectively, and the components of the pigment are determined simultaneously.