Gynostemosides A-E, megastigmane glycosides from Gynostemma pentaphyllum.

Megastigmane glycosides (1-5) together with seven (6-12) related known compounds were isolated from the whole plants of Gynostemma pentaphyllum. The structures were elucidated by means of spectroscopic methods, including 2D NMR, HR-ESIMS, and circular dichroism (CD), as well as chemical transformations to be (3R,4R,5S,6S,7E)-3,4,6-trihydroxymegastigmane-7-en-9-one-3-O-beta-D-glucopyranoside (gynostemoside A, 1), (3S,4S,5R,6R,7E,9R)-3,4,6,9-tetrahydroxymegastigmane-7-en-3-O-beta-D-glucopyranoside (gynostemoside B, 2), (3S,4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-9-O-beta-D-glucopyranoside (gynostemoside C, 3), (3S,4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-3-O-beta-D-glucopyranoside (gynostemoside D, 4), and (3S,4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-4-O-beta-D-glucopyranoside (gynostemoside E, 5), respectively.