Two New Steroidal Saponins from the Fresh Leaves of Agave sisalana

Abstract

A new furostanol saponin, sisalasaponin C (1), and a new spirostanol saponin, sisalasaponin D (2), were isolated from the fresh leaves of Agave sisalana, along with three other known steroidal saponins and two stilbenes. Their structures were identified as (3b,5a,6a,22a,25R)-3,26-bis (2), (3b,5a,6a,22a,25R)-22-methoxyfurostane-3,6,26-triyl tris-b-d-glucopyranoside, cantalasaponin-1, polianthoside D, (E)-and (Z)-2,3,4',5-tetrahydroxystilbene 2-O-b-d-glucopyranosides. The last three known compounds were isolated from the fresh leaves of Agavaceae for the first time. The structures of the new compounds were elucidated by detailed spectroscopic analysis, including 1D-and 2D-NMR experiments, and chemical techniques.

Saponins of Agave: Chemistry and bioactivity

“…Complex mixtures of sapogenins were analyzed using two-dimensional (2D) TLC over silica gel (Blunden et al, 1974). Conventionally, sapogenins and saponins of Agave were detected using 10e50% sulfuric acid followed by heating at 100 C (Blunden et al, 1980a;Sharma et al, 2012;Yi et al, 1989), Libermann-Burchard reagent (da Silva et al, 2006;Ding et al, 1993;Yu et al, 2011) (da Silva et al, 2002(da Silva et al, , 2005da Silva and Parente, 2007), respectively. Ghoghari and Rajani (2006) have developed an HPTLC method for the determination of hecogenin (1) in the leaf powder of Agave americana.…”

“…The position of this carbonyl group was ascertained by HMBC correlations with H 2 -11, -14, -17 and À18 (Perez et al, 2013;Yokosuka et al, 2000;Yu et al, 2011;Zou et al, 2006).…”

“…subcerulata (leaves) Blunden et al (1980b) A. cocui (leaves) Blunden et al (1980b) Sharma and Khanna (1980) A. filifera (leaves) Blunden et al (1978) A. avellanidens (leaves) Blunden et al (1980b) A. cerulata (leaves) Blunden et al (1980b) A. cerulata ssp. subcerulata (leaves) Blunden et al (1980b) A. cocui (leaves) Blunden et al (1980b) A. canatala (leaves) A. wightii (leaves) Khanna et al (1979) 16 (25S)-5a-Spirostan-3-one (Neotigogenone) A. sisalana (leaves) Tsung et al (1976a) 17 (25R)-5b-Spirostan-3b-ol (Smilagenin) A. lecheguilia (leaves) Blunden et al (1980a);de Rodriguez et al (2006) A. haynaldii (leaves) Blunden et al (1978) A. rigidissima (leaves) Blunden et al (1978) A. ghiesbrechtii (leaves) Blunden et al (1974) 18 (25S)-5b-Spirostan-3b-ol (Sarsasapogenin) A. attenuata (leaves) Blunden et al (1978); Mendes et al (2004) A. lophantha (leaves) Bedour et al (1979) 19 (25R)-5b-Spirostan-3b,6a-diol (Ruizgenin) A. lecheguilia (leaves) Blunden et al (1980a) (25S)-5a-Cholestane-3b,16b,22b,26-tetrol (Agavegenin D) A. americana (leaves) Jin et al (2004a) methanol (or ethanol)-water combinations (Perez et al, 2013(Perez et al, , 2014Yu et al, 2011) are generally employed for extraction. The choice of solvent also depends upon the probability of artifact formation.…”

“…Saponins are isolated from the crude extracts by size exclusion chromatography followed by normal phase silica gel chromatography (Jain, 1987;Wilkomirski et al, 1975). Final purification of the compounds is done by column chromatography over normal or reverse phase silica gel (Chen et al, 2011;da Silva and Parente, 2007;Eskander et al, 2010;Yokosuka and Mimaki, 2007;Yu et al, 2011), droplet counter current chromatography (DCCC) in descending mode (Jain, 1987) and semi-preparative high-performance liquid chromatography (HPLC) or medium pressure liquid chromatography (MPLC) (Perez et al, 2014).…”

“…over macroporous resin Mimaki, 2007, 2009;Yokosuka et al, 2000;Yu et al, 2011), or size exclusion column chromatography using Sephadex LH-20 (da Silva and Parente, 2007;Silva et al, 2005). Saponins are isolated from the crude extracts by size exclusion chromatography followed by normal phase silica gel chromatography (Jain, 1987;Wilkomirski et al, 1975).…”