The Structure of Dresgenin from Dregea sinensis var. Corrugata STRUCTURE OF DREGEOSIDE A FROM DREGEA SINENSIS VAR. CORRUGATA A NEW STEROIDAL COMPOUND OF DREGEA SINENSIS THE CONSTITUENTS OF C21-STEROIDS FROM DREGEA SINENSIS VAR. CORRUGATA Study on phenylpropanoids from Dregea sinensis var. corrugata Original plant identification of Dai nationality herb “Daibaijie”