From the commercial extract of the leaves of Stevia rebaudiana Bertoni, a minor steviol glycoside, 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(2-O-(3-O-β-D-glucopyranosyl-α-L-rhamnopyranosyl)-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl) ester] (1); also known as rebaudioside O having seven sugar units has been isolated. Its structural ch...