C-Glucosylflavonoid biosynthesis from 2-hydroxynaringenin by Desmodium uncinatum (Jacq.) (Fabaceae)

2′,3′,5′,6′-²H₄]-2-Hydroxynaringenin is synthesised and incubated with commercially available UDP-glucose and the crude protein extract from Desmoduim uncinatum leaves. The organic extract produces isotopically labelled 2′,3′,5′,6′-²H₄]-vitexin and 2′,3′,5′,6′-²H₄]-isovitexin. Repeating the experiment with denatured protein or replacing the 2-hydroxynaringenin with 2′,3′,5′,6′-²H₄]-apigenin or 2′,3′,5′,6′-²H₄]-naringenin results in no observable incorporation. 2-Hydroxynaringenin is therefore the substrate for C-glucosylflavonoid biosynthesis in D. uncinatum.