Reactive Oxygen Species Improve Quality Of Radix Scutellaria Through Antioxidant System

Scutellaria baicalensis Georgi show their nomal habit of growth with thermophilic,sun-loving,cold and drought tolertant,which is the distribution of a wide range and have a strong ability to adapt to the environment with obvious genuineness.Studies show dry climate,and ample sunshine are considered as major ecology factors relative to quality of Radix Scutellariae Plants can produce a lot of reactive oxygen species under the stress circumstances,which can induce synthesis of secondary metabolites and improve quality of herb.The fresh root of Scutellaria baicalensis Georgi is the living body and also the medicinal part.With the fresh root of Scutellaria baicalensis Georgi serving as the research object,this study discussed the effect of H2O2 and oxygen carrier Na2S2O4 on quality of Radix Scutellariae and their mechanisms.??The effect of H2O2 on quality of herb and their mechanisms1?The results indicated that the SOD and POD activities had been a modest decrease in fresh roots of S.baicalens-is treated with 0.002?mol/L,0.2?mol/L,and 20?mol/L H2O2.Especially,CAT activities decreased by 71.4?85.7%between the third-fifth day at 0.2?mol/L,and 20?mol/LH2O2 The activity fall of SOD,CAT and POD allow much more ROS to accumulate still further in the form of H2O22?H2O2 can significantly enhance the activity and gene expression of PAL.Especially,at the fifth day,the activity of PAL increased by 2.7 times,and promoted the synthesis of flavonoids.H2O2 also changed the activity of UBGAT and GUS,thus boosted transformation of flavonoid glycosides into aglycones.The expression of GUS and UBGAT was significantly increased or decreased by different concentrations of H2O2 at different times,and the activity of GUS was increased by 3 times at the fifth day.3?The results indicated that the 0.002?mol/L and 0.2?mol/L H2O2 improved biosynthesis of all flavonoids,especially at the third day,baicalin increase from 6.28%to 6.80%,wogonoside from 3.35%to 4.29%at the 0.002 ?mol/L.At 20 ?mol/L H2O2,the contents of flavonoid glycosides decreased,while the contents of aglycons increased significantly,especially at the 7th day,baicalin decreased from 6.82%to 6.15%,and wogonoside from 3.43%to 3.40%,but baicalein increased from 0.19%to 0.57%and wogonin from 0.11%to 0.30%,respectively.??The effect of Na2S2O4 on quality of herb and their mechanisms1?Na2S2O4 is O2-carrier.The results indicated that the SOD activities had a modest decrease in fresh roots of S.baicalensis treated with 0.004?mol/L,0.4?mol/L,and 40?mol/L Na2S2O4,the activities of CAT and POD were significantly decreased from the third day to the ninth day,especially CAT activities came down fast from the start,by 80?85%between the third-fifth day.The activity fall of SOD,CAT and POD allow much more ROS to accumulate still further in the form of H2O22?To activities,the Na2S2O4 showed no signs of increasing the activitiy of PAL.The 0.004?mol/L,and 0.4pmol/L Na2S2O4 made the PAL increasing slightly,the 40?mol/L Na2S2O4 promoted the PAL significantly.At the third day,the expression of PAL was increased by 4.3 times,thus promoting the synthesis of flavonoids.Na2S2O4 also changed the activity of UBGAT and GUS,thus boosted transformation of flavonoid glycosides into aglycones.But later than H2O2 group,Na2S2O4 may play a role through H2O2.The expression of GUS and UBGAT were significantly increased or decreased by different concentrations of Na2S2O4 at the third day,but did not show the dose relationship3?The effect of Na2S2O4 on the activity of PPO was delayed than that on the expression of PAL gene and antioxidative enzymes.At the fifth day,the 0.004?mol/L,and 0.4pmol/L Na2S2O4 increased PPO activities by 60?80%,scavenging excess flavonoids.While the 40?mol/L decreased by 60%,contributing to accumulation of the flavonoids4?The results indicated that the 0.004?mo]/L,and 0.4?mol/L Na2S2O4 can increase contents of flavonoid glycosides in roots to some extent,from 6.28%to 6.84%for baicalin,from 3.35%to 4.12%for wogonoside,more than aglycones at the third day.On the contrary,the 40?mol/L decreased flavonoid glycosides,and increased aglycones remarkably,most notably at the third day,baicalin fell from 6.28%to 5.21%,wogonoside from 3.35%to 2.83%,but baicalein rise from 0.28%to 1.96%,wogonin from 0.14%to 1.24%,over 7 times respectively.H2O2 and Na2S2O4 decrease activities of antioxidative enzymes to producing higher H2O2 which is well-described second messenger,enhancing the activities and the expression of PAL,GUS,UBGAT and improving transformations and synthesis of flavonoids.Finally,the PPO maintains the balance by regulating the contents of flavonoids.Quality of herb is improved by increasing the contents of secondary metabolism through ROS,especially in which strong activity of aglycone such as baicalein improve greatly.