label: 3',5-dihydroxy-3,4',7-trimethoxyflavone + S-adenosyl-L-homocysteine + H(+) => 3',4',5-trihydroxy-3,7-dimethoxyflavone + S-adenosyl-L-methionine
label_lc: 3',5-dihydroxy-3,4',7-trimethoxyflavone + s-adenosyl-l-homocysteine + h(+) => 3',4',5-trihydroxy-3,7-dimethoxyflavone + s-adenosyl-l-methionine