Four new kaempferol glycosides from the leaves of Brugmansia suaveolens
Brugmansia suaveolens (Humb. & Bonpl. ex Willd.) Bercht. & C. Presl (Syn. Datura suaveolens; Common name: Angel's trumpet) is a flouring shrub of Solanaceae family and it is native from coastal regions of the rainforest in Southeast Brazil. This plant has been investigated due to its inflammatory and wound healing activities  and mainly due to the presence of alkaloids . Nevertheless, only few studies related the characterization of flavonoid glycosides . This prompted us to investigate the ethanolic extract prepared from its leaves.
In order to have pure compounds, the plant material was submitted to successive chromatographic separations using open column chromatography and HPLC on RP-18. Up to now, four new flavonol glycosides, namely, kaempferol 3-O-β-D-glucopyranosyl-(1'''→2'')-O-α-L-arabinopyranoside-7-O-β-D-glucopyranoside (1), kaempferol 3-O-β-D-[6'''-O-(3,4-dihydroxy-cinnamoyl)]-glucopyranosyl-(1'''→2'')-O-α-L-arabinopyranoside-7-O-β-D-glucopyranoside (2), kaempferol 3-O-β-D-[2'''-O-(3,4-dihydroxy-cinnamoyl)]-glucopyranosyl-(1'''→2'')-O-α-L-arabinopyranoside-7-O-β-D-glucopyranoside (3), and kaempferol 3-O-β-D-glucopyranosyl-(1'''→2'')-O-α-L-arabinopyranoside (4) were isolated and identified by means of extensive spectroscopic methods including 1D-(1H and 13C) and 2D NMR experiments (COSY, HSQC and HMBC) as well as ESI-MS.
Acknowledgement: Financial support from the government Baden-Württemberg (Zukunftsoffensive IV) is gratefully acknowledged.
References: 1. Sebold DF (2003) Master thesis, UFRGS/Brazil. 2. Alves MN et al. (2007)J Chem Ecol 33: 297–309. 3. Begum S et al. (2006) Nat Prod Res 20: 1231–1236.