Studies On Structure, Accumulation Of Flavonoids And Baicalin In Scutellaria Baicalensis Georgi

Scutellaria baicalensis Georgi(Scutellaria Linn.)is a perennial herbaceous plant. Its root namely Chinese traditional medicine Huang-qin,is mainly officinal part. Study on Scutellaria baicalensis Georgi has been described in many reports by predecessors.Mainly includes determination of chemical constituents and clinical study of pharmacological effect.Most study on anatomical of Scutellaria baicalensis Georgi were microscopic observation of dry root.In this study,we systematically investigated the development and structure of root,stem and leaf,the structure of nutritive organs and propagative organ,distribution and the dynamic changes of flavone and baicalin have studied from different organs,different stages and different years,by using anatomy,histochemistry and phytochemistry methods.1.The development and primary structure of nutritive organs were the same to other dicotyledons.The development of root could be divided into four stages, promeristem,primary meristem,primary structure and secondary growth stage.The primary xylem is diarch.The secondary growth mainly depend on the activities of vascular cambium and cork cambium;the cork cambium originates from pericyclic cells.The structures of the two-year-old and three-year-old tap roots were similar to the one-year-old ones,while the interxylary phellem and phellem cells appear.2.The present histochemical results indicate that flavone exist all nutritive organs and mainly parenchyma of Scutellaria baicalensis Georgi.Accumulation of flavone at the beginning of young root.3.Great discrepancies about the distribution of flavone and baicalin exist in each organ of Scutellaria baicalensis Georgi.The distribution of flavone in each organ shows as follows:leaf＞flower＞root＞stem＞fruit.The distribution of baicalin in each organ appears that root is the highest,the second is flower,fruit and frond,the stem is the lowest,and root much higher than other organs.4.Great discrepancies about the accumulation of flavone and baicalin exist in each organ of Scutellaria baicalensis Georgi.Content except vegetative growth phase baicalin in root shows as follows:three-year-old＞two-year-old＞one-year-old. Obviously vegetative growth phase and wilting stage were the two peak period of baicalin in root and the vegetative growth phase was the highest.Root much higher than stem and leaf at all stages,so it indicated that root is main storing position. Content of flavone was highest in florescence stage and lowest in wilting stage.At the same stage shows as follows:three-year-old＞two-year-old＞one-year-old,and leaf＞root＞stem in all stages,so leaves were main storing position of flavone.5.Accumulation regularity of flavone and baicalin present as one falls another rises.Vegetative growth phase and wilting stage were the two peak period of baicalin in root and lowest in florescence stage.Flavone were highest in florescence stage, lowest in wilting stage.Similar situation appeared in stem and leaf.Accumulation regularity flavone and baicalin in aerial part and underground part also have similar regularity.Baicalin in underground part and flavone in aerial part have homoplastic change curve,so as baicalin in aerial part and flavone in underground part.According to this accumulation regularity,we can reasonably harvesting stems and leaves to utilizing plant resources of Scutellaria baicalensis Georgi.6.Anatomy,histochemical and phytochemistry results indicate that content of baicalin in root was the highest for vascular tissue occupied most proportion of root, and parenchyma have a large proportion in vascular tissue.Proportion of vascular tissue in stem and leaf were very small and content of baicalin of them were low.So content of baicalin of nutritive organs have close relations with their structural characteristics.Structure of plant is closely related to distribution and accumulation of their secondary metabolites.