Erysimum cheiri, (L.) Crantz

Tatsuzawa, Fumi, 2019, Acylated pelargonidin glycosides from the red-purple flowers of Iberis umbellata L. and the red flowers of Erysimum × cheiri (L.) Crantz (Brassicaceae), Phytochemistry 159, pp. 108-118 : 112

2.2. Anthocyanins in the red flowers of E. × cheiri

By HPLC analysis, four major anthocyanin peaks were detected in the 5% HOAc extract from the red flowers of E. × cheiri ‘Aurora’ ( Fig. 3 ). Percentages of the total anthocyanin contents based on HPLC peak areas at 530 nm are as follows: 7: 52.6%, 8: 7.5%, 9: 15.7%, 10: 14.4%. These anthocyanins (7–10) were isolated from the dried flowers and purified according to procedures described previously ( Tatsuzawa et al., 2006). The chromatographic and spectroscopic properties of these pigments are summarized in Experimental. Visible maxima (λ max) in 0.1% HCl-MeOH were observed at 509–510 nm. In addition, (E 440 / E vis.max) ratios were 0.22–0.23. Addition of AlCl 3 did not exhibit a bathochromic shift, indicating that these pigments lack a vicinal hydroxyl group in the B-ring. Therefore, these data suggested that 7–10 may have a pelargonidin 3,5-glycosyl type structure ( Tatsuzawa and Shinoda, 2005). The E acyl / E vis.max ratio 0.83–1.41 suggested that 7–10 had one or two hydroxycinnamic acid units ( Saito et al., 2008). Alkaline hydrolysis of 1 mg of each pigment yielded deacyl anthocyanins and hydroxycinnamic acids. The structure of the deacyl anthocyanin of pigments 7, 8, and 10 was identified as pelargonidin 3-sambubioside-5- glucoside by direct comparison of HPLC behavior with those of authentic samples obtained from Lobularia maritima (Tatsuzawa et al., 2010a) . The structure of the deacyl anthocyanin of pigment 9 was not identified at this stage. p -Coumaric acid was obtained from the alkaline hydrolysate of pigments 7, 9, and 10, but ferulic acid was obtained from the alkaline hydrolysate of pigment 8 based on comparison to authentic samples (Wako Pure chemical Industries. Ltd., Osaka, Japan). The structures of 7–10 were elucidated further as described below based on analysis of their NMR spectra in CF 3 COOD-DMSO‑ d 6 (1:9), with TMS as an internal standard.

Figures

Fig. 3. HPLC profile (530 nm) and structure of acylated anthocyanins isolated from the red flowers of E.× cheiri 'Aurora'. 7: pelargonidin 3-O-[2-O-(xylosyl)-6-O-(p-coumaroyl)-glucoside]-5-O-(glucoside). 8: pelargonidin 3-O-[2- O-(xylosyl)-6-O-(feruloyl)-glucoside]-5-O-(glucoside). 9: pelargonidin 3-O-[2-O-(2-O-(p-coumaroyl)-3-O-(glucosyl)-xylosyl)-6-O-(p-coumaroyl)-glucoside]-5-O-(glucoside). 10: pelargonidin 3-O-[2-O-(2-O-(p-coumaroyl)-xylosyl)-6-O-(p- coumaroyl)-glucoside]-5-O-(glucoside).