Converts sesamin into sesamin mono- and di-catechol. Catalyzes a ring cleavage to transfer the methylene group to tetrahydrofolate (THF). Also active with (+)-episesamin, (-)-asarinin, sesaminol, (+)-sesamolin and piperine. (+)-sesamin + (6S)-5,6,7,8-tetrahydrofolyl-(gamma-L-Glu)(n) = (+)-sesamin monocatechol + (6R)-5,10-methylenetetrahydrofolyl-(gamma-L-Glu)(n) (+)-sesamin monocatechol + (6S)-5,6,7,8-tetrahydrofolyl-(gamma-L-Glu)(n) = (+)-sesamin dicatechol + (6R)-5,10-methylenetetrahydrofolyl-(gamma-L-Glu)(n) kcat is 7.9 sec(-1) with sesamin as substrate. Optimum pH is 7.5-8.5. Optimum temperature is below 40 degrees Celsius. Homotrimer. Expression is induced in the presence of sesamin. Belongs to the GcvT family.