Table II.

Pyridine nucleotide cofactor dependency of 11(S),13-dihydrocostunolide and leucodin biosynthesis from (⁺)-costunolide

Pyridine Nucleotide Cofactor	Percentage Product Formation ± sd
	Dihydrocostunolide (17)	Leucodin   (19)
1 mm NADPH	100  ± 3a	100  ± 10a
None	15  ± 1	0  ± 0
1 mm NADH	14  ± 2	0  ± 0
1 mm NADPH + 1 mm NADH	107  ± 4	65  ± 19
1 mm NADP++ 1 mm NAD+	18  ± 3	0  ± 0

^a One hundred percent product formation corresponds to a saussurea lactone (18) and leucodin (19) peak size of 1.34 and 0.42 × internal standard (1 nmol of cis-nerolidol), respectively.