Polyhydroxylated Spirostanol Saponins from the Tubers of Dioscorea polygonoides

Abstract

Three new polyhydroxylated spirostanol saponins (1-3) were isolated from the tubers of Dioscorea polygonoides. The structures of these new compounds were determined on the basis of extensive spectroscopic analysis and the results of acid or enzymatic hydrolysis as (23S,24R,25S)-23,24-dihydroxyspirost-5-en-3beta-yl O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (1), (23S,25R)-12alpha,17alpha,23-trihydroxyspirost-5-en-3beta-yl O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (2), and (23S,25R)-14alpha,17alpha,23-trihydroxyspirost-5-en-3beta-yl O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (3), respectively.

The Dioscorea genus: a review of bioactive steroid saponins

“…The polyhydroxylated spirostanol saponins (41-43) did not exhibit cytotoxic activities against HSC-2 and HL-60 human promyelocytic leukemia cells (IC 50 > 200 lM), respectively [27].…”

“…hypoglauca [8][9][10][11][12][13], D. deltoidea var. orbiculata [14], D. futschauensis [15][16][17][18][19][20], D. nipponica [21], D. panthaica [22][23][24], D. parviflora [25], D. polygonoides [26,27], D. pseudojaponica [28], D. spongiosa [29], D. villosa [30], and D. zingiberensis [31] (Table 1). The structures of the aglycons of the isolated saponins belonged to three skeleton types: furostane, a pentacyclic ABCDE-ring system with a sixth open F ring (1-30); spirostane, a hexacyclic ABCDEF-ring system (31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46); and pregnane, a tetracyclic ABCD-ring system (47-58) (Figs.…”

“…About the E ring, a satured one can be found (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), or with insaturations in the positions 20 (22) (13)(14)(15)(16)(17)(18) or 22 (23) on the open F ring (26). A seco-furostane skeleton is equally described (27)(28)(29)(30). Moreover, in the same plant, pairs of furostanol saponins can be found constituted by the native molecule and its methyl derivative, like protoneodioscin (24) and Me protoneodioscin (25), protogracillin (3) and Me protogracillin (4), protoneogracillin (22) and Me protoneogracillin (23), from D. futschauensis.…”

Candidaspongiolides, Distinctive Analogues of Tedanolide from Sponges of the Genus Candidaspongia

“…The R-methylene signal (δ 2.24) was correlated to a carbon signal at δ 34.2 (HMQC) and adjacent to the ester carbonyl at δ 173.5 (HMBC). The upfield section of the 13 C NMR spectrum showed a diversity of chemical shifts for methyl, methylene, and methine carbons; these data, together with DEPT NMR data, led to the construction of fragments corresponding to the normal, iso, and anteiso isomers of the acyl esters.…”

“…In addition, the upfield shift and coalescence of the H 2 -28 AB pair to a broad singlet at δ 3.61 confirmed that the enzymatic reaction had affected the target ester at C-28. The comparison of 13 C NMR spectra (acetone-d 6 ) showed a downfield shift of C-28 from δ 64.6 (3, acetone-d 6 ) to δ 70.9 (4), corresponding to the transformation from an ester to a primary alcohol. The NMR spectra indicated no other modifications in the candidaspongiolide core (4), confirming a successful enzymatic hydrolysis (Table 3).…”