Provided are a sulfated C-glycoside which is a novel compound serving as a precursor of chafuroside and chafuroside analogs a method for efficiently producing the sulfated C-glycoside and a method for efficiently producing chafuroside and chafuroside analogs using said sulfated C-glycoside. A sulfated C-glycoside represented by general formula (A1) or (B1) [wherein R1, R2 and R3 independently represent each a hydrogen atom or an OH group] is obtained by extracting tea leaves or tea tannins with water, a lower alcohol solvent having 1 to 3 carbon atoms or a liquid mixture comprising the same. Alternatively, the sulfated C-glycoside is produced by reacting a flavone C-glycoside such as isovitexin or vitexin with a sulfate group-introducing agent to thereby sulfate the flavone C-glycoside. By heating the sulfated C-glycoside thus obtained, chafuroside and chafuroside analogs are efficiently produced.
