Acylated anthocyanins from leaves of Oxalis triangularis

• Published in: Phytochemistry (Oxford) Vol. 66; no. 10; pp. 1133 - 1140
• Main Authors: Fossen, Torgils, Rayyan, Saleh, Holmberg, Maya H., Nateland, Ha˚vard S., Andersen, Øyvind M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01-05-2005; Elsevier
• Subjects: 2D NMR; 4-Malonylated rhamnose; Acylated anthocyanins; acylation; anthocyanins; Anthocyanins - chemistry; Biological and medical sciences; Chemical constitution; chemical structure; Colour; Food additives; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; glucopyranoside; Leaves; Magnoliopsida - chemistry; malvidin; Molecular Structure; Oxalis; Oxalis triangularis; phytochemicals; plant extracts; Plant Leaves - chemistry; Plant physiology and development; Purple shamrock; spectral analysis; stereochemistry; Leaves; Acylated anthocyanins; 2D NMR; 4-Malonylated rhamnose; Purple shamrock; Oxalis triangularis; Colour; Anthocyanin; Plant leaf; Electrospray; Rhamnose; Pigments; Isolation
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2005.04.009

Five novel anthocyanins, the 3-(6-(4-malonylrhamnosyl)glucoside)-5-glucoside (
2), the 3-(6-rhamnosylglucoside)-5-(6-malonylglucoside) (
3), the 3-(6-(4-malonylrhamnosyl)glucoside)-5-(6-malonylglucoside) (
4), the 3-(6-(4-malonylrhamnosyl)glucoside) (
5) and the 3-(6-(
Z)-pcoumaroylglucoside)-5-glucoside (
6) of malvidin have been isolated from methanolic extracts of leaves of
Oxalis triangularis.
The novel anthocyanins, malvidin 3-
O-(6-
O-(4-
O-malonyl-α-rhamnopyranosyl)-β-glucopyranoside)-5-
O-β-glucopyranoside (
2), malvidin 3-
O-(6-
O-α-rhamnopyranosyl-β-glucopyranoside)-5-
O-(6-
O-malonyl-β-glucopyranoside) (
3), malvidin 3-
O-(6-
O-(4-
O-malonyl-α-rhamnopyranosyl)-β-glucopyranoside)-5-
O-(6-
O-malonyl-β-glucopyranoside) (
4), malvidin 3-
O-(6-
O-(4-
O-malonyl-α-rhamnopyranosyl)-β-glucopyranoside) (
5) and malvidin 3-
O-(6-
O-(
Z)-
p-coumaroyl-β-glucopyranoside)-5-
O-β-glucopyranoside (
6), in addition to the 3-
O-(6-
O-α-rhamnopyranosyl-β-glucopyranoside)-5-
O-β-glucopyranoside (
1) and the 3-
O-(6-
O-(
E)-
p-coumaroyl-β-glucopyranoside)-5-
O-β-glucopyranoside (
7) of malvidin have been isolated from purple leaves of
Oxalis triangularis A. St.-Hil. In pigments
2,
4 and
5 a malonyl unit is linked to the rhamnose 4-position, which has not been reported previously for any anthocyanin before. The identifications were mainly based on 2D NMR spectroscopy and electrospray MS.