Kim, Yang, Lee, and Kang (2011) studied the amounts of water-soluble vitamins in the Stevia leaf and callus extracts ( Table 5), and determined that the contents of folic acid, vitamin C and vitamin B2 in the leaf extracts were significantly higher than those of the callus extracts. In the leaf extract, folic acid was found to be the major compound, followed by vitamin C. In the callus extract, vitamin C was the major compound, followed by vitamin B.