Phyllodulcin is a dihydroisocoumarin found in Hydrangea macrophylla and Hydrangea serrata. It is a sweetener 400-800 sweeter than sugar. Phyllodulcin is a dihydroisocoumarin found in Hydrangea macrophylla and Hydrangea serrata. It is a sweetener 400-800 sweeter than sugar.