Hepta‐, hexa‐, penta‐, tetra‐, and trisaccharide resin glycosides from three species of Ipomoea and their antiproliferative activity on two glioma cell lines

Abstract

Six new partially acylated resin glycosides were isolated from convolvulin of Ipomoea purga, Ipomoea stans, and Ipomoea murucoides (Convolvulaceae). The structures of compounds 1-6 were elucidated by a combination of NMR spectroscopy and mass spectrometry. The structure of jalapinoside B (1) consists of a hexasaccharide core bonded to an 11-hydroxytetradecanoic (convolvulinic) acid forming a macrolactone acylated by a 2-methylbutanoyl, a 3-hydroxy-2-methylbutanoyl, and a quamoclinic acid B units. Purginoic acid A (2) contains a hexasaccharide core bonded to a convolvulinic acid acylated by a 3-hydroxy-2-methylbutanoyl unit. Stansin A (4) is an ester-type heterodimer, and consists of two stansoic acid A (3) units, acylated by 2-methylbutanoic and 3-hydroxy-2-methylbutanoic acids. The site of lactonization was located at C-3 of Rhamnose, and the position for the ester linkage of the monomeric unit B on the macrolactone unit A was established as C-4 of the terminal rhamnose. Compounds 5 and 6 are glycosidic acids. Murucinic acid II (5) is composed of a pentasaccharide core bonded to an 11-hydroxyhexadecanoic (jalapinolic) acid, acylated by an acetyl unit. Stansinic acid I (6) is a tetrasaccharide core bonded to a jalapinolic acid, acylated by 2-methylbutanoyl and 3-hydroxy-2-methylbutanoyl units. Preliminary testing showed the cytotoxicity of compounds 1-6 toward OVCAR and UISO-SQC-1 cancer cell lines. In addition, compound 1 showed an antiproliferative activity on glioma C6 and RG2 tumor cell lines. Copyright © 2016 John Wiley & Sons, Ltd.

Resin Glycosides from the Roots of Operculina macrocarpa (Brazilian Jalap) with Purgative Activity

“…Glycosidic acid 4 was subjected to acid hydrolysis to liberate the aglycone, which was further methylated, silylated, and analyzed by GC-EIMS (Figure S43, Supporting Information) to identify the hydroxy group substitution at C-11 of tetradecanoic acid, since α-cleavage to the trimethylsiloxyl group gave diagnostic ions at m/z 287 ([C 12 H 22 O 3 TMS] + ) and 145 ([C 4 H 8 OTMS] + ). Therefore, compound 4 was identified as the known (11S)-hydroxytetradecanoic acid 11- 3 This oligosaccharide core has been found in macrocyclic resin glycosides as jalapinosides I−II 14c,15b and B and also glycosylated to either (3S,11S)-dihydroxytetradecanoic or (3S,11S)-dihydroxyhexadecanoic acids, 19 in the resin glycosides isolated from the cypress-vine morning glories, I. quamoclit (Quamoclit pinnata) 20 and I. × multifida (a hybrid between I. quamoclit and I. hederifolia), 21 purgative species commonly cultivated in gardens.…”

“…Therefore, compound 4 was identified as the known (11 S )-hydroxytetradecanoic acid 11- O -β- d -quinovopyranosyl-(1→2)- O -β- d -glucopyranosyl-(1→3)- O -[β- d -fucopyranosyl-(1→4)]- O -α- l -rhamnopyranosyl-(1→2)- O -β- d -glucopyranosyl-(1→2)- O -β- d -quinovopyranoside . This oligosaccharide core has been found in macrocyclic resin glycosides as jalapinosides I–II , and B and also glycosylated to either (3 S ,11 S )-dihydroxytetradecanoic or (3 S ,11 S )-dihydroxyhexadecanoic acids, in the resin glycosides isolated from the cypress-vine morning glories, I. quamoclit ( Quamoclit pinnata ) and I. × multifida (a hybrid between I. quamoclit and I .…”

Chemistry and biological activity of resin glycosides from Convolvulaceae species

“…Quamoclinic acid B ( 3 , 7 S ‐hydroxydecanoic acid 7‐ O ‐ β ‐ d ‐quinovopyranoside) was obtained from alkaline hydrolysis of the ether‐insoluble resin glycoside fraction from the seed of Quamoclit pennata and Q. multifida 29,46 . It was shown to be the side chains of the intact resin glycosides in the following studies 47,48 …”

“…Stansoic acid A ( 13 ) was obtained by the alkaline hydrolysis of a resin glycoside dimer from Ipomoea stans , and possessed the same trisaccharide core as poranic acids A and B ( 10 and 11 ), with a different 11 S ‐hydroxyhexadecanoic acid aglycone 47 …”

“…An intact resin glycoside jalapinoside B ( 230 ) was isolated from the roots of I. purga 47 . The structure of jalapinoside B ( 230 ) was derived from purgic acid A, 96 and possessed a macrolactone formed by the aglycone acylated at the C‐3 position of the Glc.…”