Structures of some lilioglycosides from the bulbs ofLilium regale

Abstract

The chemical structures of a number of steroid glycosides isolated from the bulbs of Lilium regale Wills have been reported previously [1]. In the present paper we give proofs of the structures of six steroid glycosides obtained from bulbs of L. regale growing on the territory of the Republic of Moldova, which we have called lilioglycosides B (1), C (2), E (3), F (4), H (5), and I (6).An ethanolic extract of the fresh lily bulbs was evaporated to an aqueous residue, from which the total steroid glycosides were extracted with n-butanol. By repeated chromatography on a column of silica gel we obtained six steroid glycosides in the individual state.Lilioglycosides (3) and (4) were identified as deacylbrownioside and brownioside, which have been isolated from Lilium brownii [2, 5]. According to IR spectroscopy (920 < 900 cm-1), lilioglycosides C and I belonged to the spirostanol series with the (25R) configuration, and lilioglycosides B and H to the (25S)-spirostanol series. On complete acid hydrolysis, lilioglycoside B formed an aglycon, identified as narthogenin, and D-glucose, as was established chromatographically.The full structure of lilioglycoside B was determined by 13C NMR spectroscopy (Table 1). When the 13C NMR spectra of lilioglycoside B and diosgenin [3] were compared it became obvious from the downfield shift of the signal that there was a hydroxy group in position 27 of the genin moiety of glycoside B, while the C-3 atom experienced a glycosylation effect and resonated at t5 76.6 ppm. By the NMR-spectroscopic method for detecting NOEs in the two-dimensional variant we also detected a correlation peak of the anomeric proton of/~-D-glucopyranose with the H-3 proton of the aglycon, which showed the position of the glycosidic bond.The 13C NMR spectrum of glycoside (1), containing the signals of one D-glucose residue, determined the glycoside as a monoside. The SSCC (7.2 Hz) of the anomeric proton, H-l, and the chemical shifts of the carbon atoms of the monosaccharide residue confirmed the/~-configuration, the C1 conformation, and the pyranose form of the D-glucose residue.Consequently, the chemical structure of the new steroid glycoside lilioglycoside B is described by the formula 3-O-/~-Dglucopyranosyl (25S)-spirost-5-ene-3/3,27-diol.The IR spectrum of lilioglycoside C revealed a band at 1725 cm -1, characteristic for a carbonyl group. Analysis of the products of the complete acid hydrolysis of glycoside (2) permitted the identification of D-glucose and of narthogenin as

Steroidal glycosides from Allium cyrillii bulbs

“…The CSs of the methylene protons of this substituent were G 2.75, 2.93, 2.84, and 3.07 ppm; of the methyl protons, 1.57 ppm. A comparison of these values with the literature [7] confirmed that glycoside 1 contained HMG. The acid was bonded at O-4 of a xylose unit as indicated by the weak-field CS of H-4ss (G 5.17) compared with that of 2 (4.12), which did not contain an HMG residue (Table 2).…”

Novel steroidal saponins from Dioscorea esculenta (Togedokoro)

“…Among them 9, 11, 14, and 15 were determined to be novel compounds. This is the first isolation of 1-15 from D. esculenta, though 1-5, 7, and 8 have already been isolated from Dioscorea spp., [28][29][30] and 6, 10, 12, and 13 have also been isolated from various plants 8,[20][21][22] The present study would be very useful to investigate the characteristics of saponins in Dioscorea spp.…”

“…Based on MS, 1 H-, and 13 C NMR spectra, the isolated three steroidal sapoinins, compound 1, 2, and 3, were identified as protodioscin (1), 8) dichotomin (2), 9,10) and protogracillin (3), 11,12) which are furostanetype saponins. Compound 4, 5, 7, 8, 10, 12, and 13 were identified as dioscin (4), 13,14) prosapogenin A (5), 15) parrisaponin (7), 16) gracillin (8), 17,18) 13 C NMR (151 MHz) data of sugar moiety of 9, 11, 14, and 15 in C 5 D 5 N. (1 → 2)]-β-D-glucopyranoside (10), 16) 19) and (25R)-spirost-5-ene-3β, 27- 20,21) which are spirostane-type saponin. Also, compound 6 was estimated as (25R)-spirost-5-en-3β-ol-3-O-α-L-rhamnopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside of spirostanetype saponin by 1 H NMR and ESI-MS data compared with those spectra data reported previously (Fig.…”

Chemistry and biological activity of steroidal glycosides from the Lilium genus

“…27). 91 The lily bulbs used in the study were collected in the territory of the Republic of Moldova. Lilium speciosum  Lilium nobilissimum (Makino) Makino (Fig.…”

“…27). 91 The lily bulbs used in the study were collected in the territory of the Republic of Moldova. Compound 48 was determined to be a b-D-glucopyranoside of 27-hydroxydiosgenin, narthogenin, and had a (S) conguration at the C-25 position.…”