There are also other
related compounds including Rebaudioside-C, D, &
E and Dulcoside-A&C, as well as minor glycosides
that are found in very small quantities in the leaf.
They are less sweet and also contribute to the bitterness.
A typical stevia extract that combines all 6 glycosides
is around 250 sweeter than sugar and has a strong
bitter menthol-like aftertaste.