Baimantuoluosides D-G, four new withanolide glucosides from the flower of Datura metel L.

In our search for bioactive anti-psoriasis compounds from the flower of Datura metel L, we isolated four new withanolide glucosides, baimantuoluosides D, E, F and G (1-4). The structures of the new compounds are (5alpha,6alpha,7beta,22R)-5,6,7,27-tetrahydroxy-1-oxowitha-2,24-dien-27-O-beta-D-glucopyranoside (1), (5alpha,6beta,7alpha,22R)-5,6,7,27-tetrahydroxy-1-oxowitha-2,24-dien-27-O-beta-D-glucopyranoside (2), (5alpha,6beta,7alpha,12beta,22R)-5,6,7,12,27-pentahydroxy-1-oxowitha-2,24-dien-27-O-beta-D-glucopyranoside (3), and (5alpha,6beta,22R)-5,6,27-trihydroxy-1-oxowitha-2,24-dien-27-O-beta-D-glucopyranoside (4) on the basis of chemical and physicochemical evidence.