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Two new glycosidic acids, calyhedic acids E (1a) and F (2a), were isolated from the glycosidic acid fraction afforded by alkaline hydrolysis of the crude resin glycoside fraction obtained from whole plants of Calystegia hederacea Wall. Compounds 1a and 2a were characterised as 11S-hydroxyhexadecanoic acid 11-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl-(1→3)-[O-α-L-rhamnopyranosyl-(1→2)]-O-β-D-glucopyranosyl-(1→2)-β-D-quinovopyranoside and an isomer of 1a, in which the 11S-hydroxyhexadecanoyl residue of 1a was replaced by a 12S-hydroxyhexadecanoyl residue, respectively, on the basis of spectroscopic data. [ABSTRACT FROM AUTHOR]

Resin glycosides act as laxatives in crude drugs derived from plants of the Convolvulaceae family. These compounds have exhibited antibacterial, ionophoric, anti-inflammatory, antiviral, and multidrug resistance-modulating properties, as well as cytotoxicity against cancer cells. This study investigated the organic acid, hydroxyl fatty acid, monosaccharide, and glycosidic acid components of the crude resin glycoside fraction obtained from the methanol extract of Ipomoea alba L. (Convolvulaceae) seeds, which was subjected to alkaline and acidic hydrolysis. The alkaline hydrolysis yielded acetic, isobutyric, (E)-2-methylbut-2-enoic, and 2 S -methyl-3 S -hydroxybutyric acids as organic acid components, along with a glycosidic acid fraction. The acidic hydrolysis of the glycosidic acid fraction resulted in the isolation of 11 S -hydroxytetradecanoic and 11 S -hydroxyhexadecanoic acids as hydroxyl fatty acid components, as well as d -glucose, d -quinovose, d -fucose, d -xylose, and l -rhamnose as monosaccharide components. In addition, 10 new glycosidic acid methyl esters were isolated from the glycosidic acid fraction treated with trimethylsilyldiazomethane–hexane, along with one known glycosidic acid methyl ester. Of these, eight compounds contained new glycans. Four of these compounds were unusual natural glycosides with four glycosidic linkages to one monosaccharide. Their structures were determined using MS and NMR spectral analyses, which provided valuable insights into the unique glycosidic composition of I. alba seeds. [Display omitted] • The components of the resin glycoside fraction of Ipomoea alba were studied. • Ten new glycosidic acids were isolated as methyl esters. • Of the glycosidic acid methyl esters isolated, eight contained new glycans. • Four methyl esters had four glycosidic linkages to one monosaccharide. [ABSTRACT FROM AUTHOR]

Resin glycosides are commonly found in plants belonging to the Convolvulaceae family. Ipomoea lacunosa L. (Convolvulaceae) is an herbaceous vine native to the United States. The resin glycosides of this plant have not been studied in detail. In this study, the components of the crude resin glycoside fraction extracted from the seeds of I. lacunosa are characterized. Alkaline hydrolysis of the crude resin glycoside fraction obtained from methanolic extract of the seeds yielded three organic acids, namely, 2 S -methylbutyric, (E)-2-methylbut-2-enoic, and 2 R -methyl-3 R -hydroxybutyric acids, and a glycosidic acid fraction. Acidic hydrolysis of the glycosidic acid fraction yielded hydroxyl fatty acid components, including 7 S -hydroxydecanoic, 11 S -hydroxytetradecanoic, 11 S -hydroxyhexadecanoic, 3 S ,11 S -dihydroxytetradecanoic, 3 S ,11 S -dihydroxyhexadecanoic, and 3 S ,12 S -dihydroxyhexadecanoic acids, as well as monosaccharide components, including d -glucose, d -quinovose, d -fucose, and l -rhamnose. Trimethylsilyldiazomethane–hexane treatment of the glycosidic acid fraction further yielded eleven previously undescribed glycosidic acid methyl esters and two known glycosidic acid methyl esters. The structures of the obtained compounds were characterized using various spectral techniques. Four of the undescribed compounds were hexaglycosides, five were heptaglycosides, and two were octaglycosides. The aglycone of these compounds was either methyl 11 S -hydroxytetradecanoate, methyl 3 S ,11 S -dihydroxytetradecanoate, or methyl 3 S ,11 S -dihydroxyhexadecanoate. Among the undescribed compounds identified, eight contained novel glycans, and three were rare bisdesmosides with sugar linkages at the C-3 and C-11 positions of methyl 3 S ,11 S -dihydroxytetradecanoate. [Display omitted] • Thirteen glycosidic acid components of I. lacunosa were isolated as methyl esters. • Of the glycosidic acid methyl esters isolated, eleven were undescribed compounds. • Eight glycosidic acid methyl esters contained undescribed glycans. • Two of the undescribed glycosidic acid methyl esters were octaglycosides. • Three glycosidic acid methyl esters were rare bisdesmosides. [ABSTRACT FROM AUTHOR]