<;P>;PROBLEM TO BE SOLVED: To provide a new substance which is originated from a natural product, has a Ca<;SP>;2+<;/SP>;signal transduction inhibition action, and is useful as a medicine for preventing and treating excess immunoreactions, allergies, cancer, Alzheimer's disease, type 2 diabetes, hypertension, angina, and the like. <;P>;SOLUTION: This anthracobic acid compound represented by the general formula (1) or (2) (R<;SP>;1<;/SP>;and R<;SP>;2<;/SP>;are each identically or differently H or methyl; n<;SB>;1<;/SB>;and n<;SB>;2<;/SB>;are each identically or differently an integer of 1 to 5). <;P>;COPYRIGHT: (C)2007,JPO&INPIT