Early sensory tests led to claims that rebaudioside A was 150 to 320 times sweeter than sucrose, stevioside was 10 to 270 times sweeter, rebaudioside C 40 to 60 times sweeter, and dulcoside A 30 times sweeter.  However, a more recent evaluation found rebaudoside A to be about 240 times sweeter, and stevioside about 140 times.  Rebaudioside A also had the least bitterness and aftertaste.  The relative sweetness seems to vary with concentration: a mix of steviol glycosides in the natural proportions was found to be 150 times sweeter than sucrose when matching a 3% sucrose solution, but only 100 times sweeter when matching a 10% sucrose solution. 
Cyanogenic glycosides are secondary plant compounds that occur widely in the plant kingdom. They are the source of HCN which can render the plant toxic if it is taken as food. The enzymes responsible for production of the HCN have long been known. More recent biosynthetic studies have established certain protein amino acids as precursors of the aglycones, and indicate N-hydroxyamino acids, aldoximes, nitriles and alpha-hydroxynitriles as intermediates. In sorghum the several biosynthetic enzymes catalyzing the flow of carbon atoms from L-tyrosine through such nitrogenous intermediates are located in a membrane fraction and may be capable of metabolic channeling.