The crude drug"Cinnamomi Cortex"the bark of Cinnamomum cassia BLUME and other plants of the same genus (Lauraceae) is well described in herbals or medicinal books of Chinese medicine, and has been used medicinally from old times. This important crude drug is clinically prescribed for sweating, anti-pyretic, and analgesic effects in many Chinese medicine and widely used for aromatic stomachics as folk remedy or spice in the world. In the course of search for active anti-inflammatory constituents in the crude drugs and plants, an aqueous methanolic (1 : 1, v/v) extract from the bark of Cinnamomum sieboldii MEISSN. was found to have the potent inhibitory activity of the formation of granulation tissue through the screening by the fertile egg method. Exploration on the bark of this plant resulted in the isolation of the known (-)-epicatechin (1), (+)-catechin (2), procyanidin B2 (5), and procyanidin B4 (6), and new compounds named cinnamonol D1 (9), and cinnamonol D2 (10) as their acetates, respectively. The activity increased in the order of monomers, dimers, and trimers.
