Phenols from roots and rhizomes of Sinopodophyllum emodi Phenols from roots and rhizomes of Sinopodophyllum emodi Resources of survey in rare and endangered medicinal plant Sinopodophyllum emodi Determination of Podophyllotoxin Content in the Root andd Rhizoma of Podophyllum emodi Wall.by HPLC Research progress in Sinopodophyllum emodi