| abstract |
The present invention relates to a method for prevention or treatment of periodontal diseases, containing administering lignans represented by the following formula (1) n n(wherein R 1 represents a hydrogen atom or a hydroxyl group; R 2 , R 3 , R 4 and R 5 are the same or different and each represents a hydrogen atom, a hydroxyl group, a C 1-10 alkyl group, a hydroxy C 1-10 alkyl group or a C 1-10 alkoxy group) or plant extracts containing the lignans. |