Yingzhaosu B(I),C₁₅H₂₆O₃, isolated from the roots of yingzhao (Artabotrys uncinatus (L.) Merr.) (Anonaceae),is another biologcally active principle alongside of yingzhaosu A^[1].On the basis of chemical degradations and spectroscopic analysis(UV.IR.MS.NMR.)of yingzhaosu B and its derivatives, it was shown to have structure I.