Two new amide alkaloids from the flower of Datura metel L.

Two new amide alkaloids were isolated from the alkaloidal fraction of Datura metel L. Their structures were elucidated as (E)-methyl 4-(3-(4-hydroxyphenyl)-N-methylacrylamido) butanoate and 6,7-dimethyl-1-D-ribityl-quinoxaline-2,3(1H,4H)-dione-5'-O-β-D-glucopyranoside on the basis of spectroscopic methods including HRESIMS, 1D and 2D NMR. Tropane alkaloids have for a long time been considered as characteristic ingredients of D. metel. However, the presence of amide alkaloids in D. metel was reported for the first time in this study.