Triterpenoid Saponins from Ilex kudincha

Abstract

Ten new triterpene saponins, ilekudinosides A-J (2, 6-8, 10, 13-17), together with seven known triterpene saponins, ilexoside XLVIII (1); cynarasaponin C (5); latifolosides A (9), C (3), G (12), and H (4); and kudinoside G (11), were isolated from an aqueous extract of the leaves of Ilex kudincha. They possessed oleanane- and ursane-type triterpenoids as the aglycons. The structures were elucidated by 1D and 2D NMR experiments, including ROE difference, HOHAHA difference, 1H-1H COSY, and 1H-13C COSY (HMQC, HMBC) methods and sugar analysis. Compounds 1 and 5 exhibited acyl CoA cholesteryl acyl transferase (ACAT) inhibitory activity.

Chemical Constituents, Antischistosomal and Antioxidant Activities of the Methanolic Extract of Azadirachta indica

“…Also, the downfield shift of C-3 of the arabinose unit at δ 83.02 reflected that the C-3 is the position of the interglycosidation linkage between the sugar units (36) . These results supported that compound 5 has a bidesmosidic structure (41,38) . Also, the carbon and proton resonances for the aglycone moiety of compound 5 were identical with the reported signals of pomolic acid (19α-hydroxy ursolic acid) except for C-3 and C-28 which reflected that compound 5 is bidesmosidic glycoside (40,38) .…”

“…The signal of C-28 appeared at δ 176.87 ppm in 13 C-NMR spectrum as well as the appearance of the absorption band of the ester carbonyl group in IR spectrum at 1735 cm -1 indicated that one glycosidation linked at C-28 through carboxylic group. This was confirmed by presence of signal of one anomeric carbon at δ 94.51 (41,38) . Other glycosidation linkage was suggested at C-3 of the aglycone by downfield shifts of C-3 at δ 88.42.…”

“…Also, the appearance of the signal of anomeric carbon of one glucose unit at δ 94.96 suggested that compound also has a 28-O-glycosidic linkage. This was supported by appearance of signal of C-28 at 176.40 and appeariance of ester group at 1736 cm -1 in the IR spectrum of the compound (37,38) . All of 1 H and 13 C-NMR spectroscopic signals of the aglycone were identical with the reported signals of ursolic acid except for C-3 and C-28 which reflected that compound 4 is bidesmosidic saponin (35,37,38) .…”

Triterpenes and new saponins from Ilex chamaedryfolia: chemotaxonomic tool to ilex species differentiation

“…17 The β configuration for the glucopyranosyl and glucuronopyranosyl units and the a configuration for the arabinopyranosyl residues were inferred from their 13 C-NMR data and J values. 18 These data suggested that 5 is the 3β-O-β-D-glucuronopyranosyl-20(R)-19a-hydroxyurs-12-en-28-oic acid 28-O-β-D-glucopyranosyl ester (Figure 1) which was already isolated from Ilex kudincha by Nishimura et al 15 as ilekudinoside B. To the best of our knowledge, the saponins 3 and 4 reported herein have not been yet described in the literature.…”

“…After detailed analysis of the spectroscopic data of 4 it was possible to conclude that this compound contained a single glucose residue in the ester chain at C-28, contrasting to 3a and 3 that contained two glucose units. in Ilex kudincha 15 and Randia formosa. 16 Thus, 4 is the epimer of ilekudinoside E and randiasaponin III.…”