Identification and Characterization of Component Organic and Glycosidic Acids of Crude Resin Glycoside Fraction from Calystegia soldanella

Abstract

NoteCalystegia soldanella ROEM. et SCHULT. (Convolvulaceae) is widely distributed on temperate sandy beaches of seas and lakes. The root of this plant is used for the treatment of arthritis.1) The isolation and structural elucidation were reported for two genuine resin glycosides, soldanellines A and B, as chemical constituents of the root.2,3) Prior to reinvestigation of the genuine resin glycosides of this plant, we examined the chemical components of the crude resin glycoside fraction of the leaves, stems, and roots of C. soldanella. This paper deals with the isolation and structural elucidation of four new glycosidic acids along with one known glycosidic acid and three known organic acids.The flesh leaves, stems, and roots of C. soldanella were extracted with methanol (MeOH). This extract was partitioned between ethyl acetate (EtOAc) and H 2 O. The EtOAcsoluble fraction was subjected to Sephadex LH-20 column chromatography to afford a crude resin glycoside fraction. The alkaline hydrolysis product of part of the fraction was fractionated into organic acid and glycosidic acid fractions.The organic acid fraction was acylated with p-bromophenacyl bromide followed by chromatographic separation to give p-bromophenacyl 2-methylbutyrate (1), p-bromophenacyl tiglate (2), and p-bromophenacyl nilate (3) (Fig. 1).4) The absolute configurations of 1 and 3 were defined as S and 2S,3S, respectively, by comparison of the specific rotations and 1 H-NMR spectral data for (ϩ)-a-methoxy-a-trifluoromethylphenylacetic acid (MTPA) ester (3a) of 3 with those of authentic samples (Fig. 1). 4)Acidic hydrolysis of the glycosidic acid fraction gave aglycone and monosaccharide fractions. Methylation of the former with trimethylsilyldiazomethane-hexane yielded methyl 11S-jalapinolate (4), which was identified by 13 C-NMR spectral data of 4 and 1 H-NMR spectral data of (ϩ)-MTPA ester (4a) of 4 (Fig. 1). 5,6) HPLC analysis with optical rotation chiral detection of the monosaccharide fraction indicated the presence of D-glucose, D-quinovose, and L-rhamnose.The glycosidic acid fraction was treated with trimethylsilyldiazomethane-hexane and then chromatographed over HPLC on the octadecyl silica (ODS) and silica gel column to yield five methyl esters (5-9) of glycosidic acids. Upon alkaline hydrolysis, 5-9 gave the free glycosidic acids 5a-9a, respectively. Compound 5a was identified as soldanellic acid B based on the physical and spectral data (Fig. 1). 3)Compound 6a, named calysolic acid A, was obtained as an amorphous powder and showed an [MϪH] Ϫ ion peak at m/z 1049 along with fragment ion peaks at m/z 887 [1049Ϫ162 (hexosyl unit)] Ϫ in the negative-ion FAB-MS (Fig. 2). The molecular formula of 6a was analyzed as C 46 H 82 O 26 by high-resolution (HR)-negative-ion FAB-MS. The 1 H-NMR spectrum of 6, which was similar to that of 5 except for the appearance of signals due to one more glucosyl unit, showed signals due to five Human and Environmental Studies, Kyoto University; Japan: c Faculty of Pharmaceutical Sciences, Fukuoka Universit...

Calysolins X–XIII, Resin Glycosides from <i>Calystegia soldanella</i>, and Their Antiviral Activity toward Herpes Simplex Virus

“…2) In order to clarify the positions of the ester linkages, the 1 H-NMR signals due to the sugar moiety of 1 were assigned on the basis of 1 H-1 H correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond correlation (HMBC) spectra (Tables 1, 2). By comparing the chemical shifts of the 1 H-NMR signals between 1 and 5a, 2) the downfield shifts (Δδ= δ1-δ5a) due to acylation were observed for signals assignable to H-2 (Δδ= 1.21) and H-4 (Δδ= 1.46) of the rhamnosyl residue (Rha) and H-2 (Δδ=ca. 1.61) of the second glucosyl residue (Glc′).…”

Calysolins V–IX, Resin Glycosides from <i>Calystegia soldanella</i> and Their Antiviral Activity toward Herpes

“…The 1 H-and 13 C-NMR spectra indicated that 2 is composed of 1 mol each of tiglic acid and 6 and 2 mol of 2-methylbutyric acid (Tables 1, 2 2) showed acylation shifts (Δδ= δ2-δ6a) of signals due to H-2 (Δδ= 0.95) and H-4 (Δδ= 1.46) of Rha and H-2 (Δδ=ca. 1.51) and H-3 (Δδ=ca.…”

“…The obtained extract was suspended in H 2 O and then extracted successively with ethyl acetate and n-butanol. The ethyl acetate-soluble fraction was subjected to silica gel column chromatography and HPLC on octadecyl silica (ODS) and naphthylethyl group bonded silica to yield five resin glycosides (1)(2)(3)(4)(5). H-NMR spectrum with that of an authentic sample.…”

“…Compounds 1-5, calysolins I (9)-IV (12), and soldanelline B (13) were evaluated for their anti-HSV-1 activity, 5) as a previous examination of the crude resin glycoside fraction 2) of this plant indicated such activity (EC 50 of anti-HSV-1 The EC 50 values of all compounds except 12 were ca. 8-to 22-fold of that of acyclovir, which is used for the treatment of HSV infections, and the activity of 12 was slightly weaker than that of 1-5, 9-11, and 13 (Table 5).…”

“…The compounds were of two macrolactone types-one having a 22-membered ring (1)(2)(3)(4) and the other with a 27-membered ring (5). The sugar moieties of 1-5 are found to be partially acylated by some organic acids (2S-methylbutyric acid and tiglic acid).…”