Phytochemistry, 28(5): 1503-1506 (1989)
ANTHOCYANIDIN MALONYLGLUCOSIDES IN FLOWERS OF HIBISCUS SYRIACUS
JONG HWA KIM, GEN-ICHIRO NONAKA, KUNIMITSU FUJIEDA and SHUNPEI UEMOTO

Table I. Rf values and retention times (R,) of anthocyanins (1-12)

  R, (x 100) in* Rf
(min)
Pigment BAW BuHCl 1% HCl HOAc-HCl
Delphinidin 3-O-glucoside (1) 26 11 4 17  8.62
Cyanidin 3-O-glucoside (2) 38 24 7 26 11.29
Petunidin 3-O-glucoside (3) 34 14 4 21 13.48
Pelargonidin 3-O-glucoside (4) 48 36 12 34 14.47
Peonidin 3-O-glucoside (5) 46 31 8 32 16.21
Malvidin 3-O-glucoside (6) 40 15 6 30 18.53
Delphinidin 3-O-malonylglucoside (7) 32 22 5 23 17.15
Cyanidin 3-O-malonylglucoside (8) 43 39 15 32 20.73
Petunidin 3-O-malonylglucoside (9) 38 29 6 30 22.74
Pelargonidin 3-O-malonylglucoside (10) 57 48 16 39 24.14
Peonidin 3-O-malonylglucoside (II) 52 42 14 38 25.97
Malvidin 3-O-malonylglucoside (12) 51 35 12 37 27.08
*Rf values were measured on microcrystalline cellulose TLC in the solvents of BAW; n-BuOH-HOAc-H2O (4: 1:5), BuHCl; n-BuOH-2 M HCl (1: 1), 1% HCl; conc HCl H2O(3:97), and HOAc-HCl;H2O-HOAc HCl (82:15:3).

Thus, 8‑12 are 3‑O-(6"‑O‑malonyl)-β-D-glucopyranosides of cyanidin, petunidin, pelargonidin, peonidin and malvidin, respectively. The cyanidin malonate (8) was found to be abundant in the petal eyes of all the cultivars examined so far (about 30%), malvidin (12) in blue petal tips (about 50%), and petunidin (9) and delphinidin (7) in most mauve flowers (about 30% in total), while pelargonidin (10) and peonidin (11) were invariably minor components.

Hibiscus syriacus has very diverse anthocyanidin compositions compared with those of other Hibiscus species. A survey of Malaysian Hibiscus [6] and other preliminary studies [7‑13] have shown that only delphinidin and cyanidin glycosides are contained in the Hibiscus species. Furthermore, acylated anthocyanins were not reported previously. The reason why acylated anthocyanins were not detected in the previous reports of H. syriacus [1,2] and related species [6‑13] may be explained by the classical methodology which employs methanolic HCl for the extraction and purification. Hence, it is emphasized that more precise reexamination of the anthocyanins of Hibiscus will be required. Recently, many zwitterionic anthocyanins were discovered [4, 14, 15] and the function of such acylations in living cells were discussed [4,16]. However, the role of such acylated anthocyanins, especially that of mono and diglucosides, in flower colour production is not fully resolved.

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Hibiscus syriacus biblio