label: 3',4',5-trihydroxy-3,6,7-trimethoxyflavone + S-adenosyl-L-homocysteine => 3',4',5,6-tetrahydroxy-3,7-dimethoxyflavone + S-adenosyl-L-methionine
label_lc: 3',4',5-trihydroxy-3,6,7-trimethoxyflavone + s-adenosyl-l-homocysteine => 3',4',5,6-tetrahydroxy-3,7-dimethoxyflavone + s-adenosyl-l-methionine