label: 3',4',7,8-tetrahydroxyflavone + S-adenosyl-L-methionine = 4',7,8-trihydroxy-3'-methoxyflavone-7-olate + S-adenosyl-L-homocysteine + H(+)
label_lc: 3',4',7,8-tetrahydroxyflavone + s-adenosyl-l-methionine = 4',7,8-trihydroxy-3'-methoxyflavone-7-olate + s-adenosyl-l-homocysteine + h(+)