Hypoglycemic effects of aqueous extract from Taraxaci Herba on diabetic rats induced by Streptozotocin and its mechanism Determinationofcichoricacid,caffeicacid,andchlorogenicacidinTaraxaci Herba by HPLC ISSR analysis on genetic diversity of Taraxaci Herba ISSR analysis on genetic diversity of Taraxaci Herba