Isolation and identification of polyphenolic compounds from aerial parts of Corispermum marshallii Steven

Corispermum marshallii Steven is an herbaceous annual plant material belonging to the Amaranthaceae family. In Poland this plant is a domesticated species occurring in open, gravelly or sand habitats. In the literature there are no studies considering the polyphenolic composition of the aerial parts of any Corispermum species. Available research shows, that plant materials belonging to this genus contain ecdysteroids and some isoquinoline alkaloids including salsoline and salsolidine.

The aim was to isolate and characterise major flavonoids occurring in aerial parts of C. marshallii.

The plant material was collected on Vistula river banks, then dried aerial parts were extracted with acetone-MeOH-H2O. Solvents were evaporated under reduced pressure and water residue fractionated by liquid-liquid extraction with chloroform, diethyl ether, ethyl acetate and n-butanol. Ethyl acetate and n-butanol fractions were separated using column chromatography and preparative HPLC.

Thirteen major polyphenols were isolated. Their structures were established based on 1D and 2D NMR experiments and MS/MS analysis. All obtained compounds were classified as flavonoids – quercetin, patuletin or spinacetin derivatives. Hyperoside (1) and patuletin 3-O-β-D-galactopyranoside (2) were found as dominating constituents. Additionally, six other patuletin glycosides were isolated, including: 3-O-β-D-galactopyranosyl-7-O-β-D-glucopyranoside (3), 3-O-(6''-O-β-D-glucopyranosyl)-β-D-galactopyranoside (4), 3-O-(6''-O-α-L-arabinopyranosyl)-β-D-galactopyranoside (5), 3-O-(2''-O-(5'''-O-α-L-arabinopyranosyl)-β-D-apiofuranosyl)-β-D-galactopyranoside (6), 3-O-(2''-O-β-D-apiofuranosyl)-β-D-galactopyranoside (7) and 3-O-β-D-galactopyranosyl-7-O-(6'''-O-feruloyl)-β-D-glucopyranoside (8). Moreover, three spinacetin derivatives – 3-O-β-D-galactopyranoside (9), 3-O-β-D-galactopyranosyl-7-O-β-D-glucopyranoside (10) and 3-O-β-D-galactopyranosyl-7-O-(6'''-O-feruloyl)-β-D-glucopyranoside (11) were identified. Other identified glycosides were 6-methoxykaempferol 3-O-β-D-galactopyranoside (12) and naringenin 8-C-β-D-glucopyranoside (13).

All compounds were detected in the analysed plant material for the first time. Nine of the isolated flavonoid glycosides (compounds 3 – 11) are new natural products.

Fig. 1