Study And Application On The Electrochemical Voltammetric Method Of Electroactive Components In Medicinal Plant

There are many plenty medicinal plants in Xinjiang. In this paper, use the electrochemical method to investigate the electroactive components of some officinal medicinal plants in Xinjiang, such as Arnebia euchroma(Royle) Johnst,Rhubarb,G. uralensis. The methods for the determination of concentration in the plant by experiment were systematically studided as well as the reaction mechanism of electroactive components.1.Investigate the electrochemistry behavior of electroactive components in those medicinal plants was developed by using the method of line sweep polarography. It is showed that the best experiment condition as follows :(1) Shikonin at hanging mercury electrode in solution of 0.2mol/L HAc-NaAc (pH=4.3), the inception potential is 0V, scan rate is 300mV/s, the accumulate time is 100s. (2) Emodin at hanging mercury electrode in solution of 0.1mol/L Britton-Robinson (pH=5.72), the inception potential is 0V, scan rate is 300mV/s, the accumulate time is 100s. (3) Naringin in solution of 0.05mol/L KCl and Rutin in 0.1mol/L Tris-HCl(pH=8.3), they both at droping mercury electrode, the inception potential is -0.6V, scan rate is 400mV/s, the accumulate time is 150s. All of above have sensitive reduction peak at mercury electrode by line sweep polarography. Ep and ip can used to be qualitative and quantitative of those electroactive components .2.By the best experiment condition, we can build the electrochemistry methods to determination the electroactive components in medicinal plants in Xinjiang. (1) The peak current was proportional to the concentration of shikonin over the range of 5×10-7～1×10-5mol/L, r=0.9978. The propose method has been applied to the determination of the shikonin in Arnebia euchroma(Royle) Johnst sample, it is showed that the average recovery is 99.6%, RSD is 0.529%. (2) The peak current was proportional to the concentration of emodin over the range of 1×10-6～1.5×10-5mol/L. The propose method has been applied to the determination of the emodin in Rhubarb sample, it is showed that the average recovery is 102.5%, RSD is 0.31%. (3) The peak current was proportional to the concentration of naringin and rutin over the range of 5×10-6～1.5×10-5mol/L and 7×10-7～9.8×10-6mol/L. The propose method has been applied to the determination of the flavonoid in G. uralensis sample, average recovery is 99.1%, RSD is 0.303%.3.The reaction mechanism of electroactive components was also discussed by use the method of cyclic voltammetric. The result showed as follows:(1) Shikonin's electrode reaction process was double electron transfer and reversible with reactant adsorption. (2) Emodin's electrode reaction process was double electron transfer and pre-reversible with polymerization.(3) Naringin and Rutin's electrode reaction process both was double electron transfer. Naringin is irreversible with adsorption, and rutin is pre-reversible with adsorption.The results indicated that: the electrochemical methods was a rapid and sensitive analytical method for the quality control of those above medicinal plants, it has successfully employed to determine the concentration determination of the electroactive components in plant and this study can provided support for investigation on pharmacological and reaction mechanism, also this paper would promote the utilization and it is sure to be helpful to researches and exploitation of the officinal medicinal plant in Xinjiang.