Four New Steroid Constituents from the Waste Residue of Fibre Separation from Agave americana Leaves

Abstract

The genus Agave belongs to the Agavaceae family with more than 300 species and occurs natively in arid and tropical regions of western hemisphere, particularly Mexico, and Central America. Among which, several species are of global economic importance, e.g., Agave sisalana, the source of sisal fibre, and other species, such as A. americana, growing world-wide as ornamentals. In China, several species of the genus Agave, such as A. americana and A. sisalana, are widely cultivated in the south part for the fibre industry and as important horticultural plants.Agave americana L., a very large plant with rosettes up to 12 feet broad, is used as an important source for not only textile fibre, but also steroidal sapogenins such as hecogenin and tigogenin in China.1,2) The plant is also used as folk medicine for its antiinflammatory and anti-fungus effects on the treatment of uterus blooding, scabies, etc.3) Since the chemical investigation on the fermented residues of the leaf-juice of A. sisalana led to the identification of some tigogenin glycosides, 4,5) a lot of steroidal sapogenins and saponins were found from the fresh leaves and the fermented leaves of A. americana. [6][7][8][9][10][11][12][13][14] In a continuation of search for the bioactive saponins produced by agavaceous plants, and to utilize properly the fermented waste residue of A. americana, we have further studied the steroids constituents in the waste residue of fibre separation from A. americana leaves. As the result, three new steroid saponins, agamenosides H-J (1-3), and a new cholestane steroid agavegenin D (4), were isolated, together with six known steroids. This paper deals with a full account of the isolation and structural elucidation of these compounds. Results and DiscussionThe MeOH extract of the waste residue of fibre separation from A. american leaves was partitioned by n-BuOH and water. The n-BuOH layer was chromatographed successively over silica gel and RP-8 to afford compounds 1-4 and six known steroids, identified as (25R)-5a-spirostane-3b,6a-diol (chlorogenin),

Saponins of Agave: Chemistry and bioactivity

“…A hydroxyl unit at C-20, however, leads to an upfield shift (2e3 ppm) in C-22 (Yokosuka and Mimaki, 2007). C-23 and C-24 hydroxyls, as in the case of agamenosides H (41) and I (35), shifts the C-22 signal to lower field by 2e4 ppm (Eskander et al, 2010;Jin et al, 2004a). Furostanol glycosides either have a free hydroxyl or a methoxyl group at C-22.…”

“…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.…”

“…Cytotoxicity against HL-60 cells (modified MTT assay) (NA at 10 mg/mL) Jin et al (2004a); Yokosuka and Mimaki (2007) …”

Antifungal Activity of C-27 Steroidal Saponins

“…Thus, from the perspective of structure-activity relationships (SAR), 22 steroidal saponins with a spirostanol skeleton and 6 steroidal sapogenins isolated from several monocotyledonous plants (8)(9)(10)(11)(12)(13)(14)(15)(16) and belonging to different chemotypes were selected for this study. This selection was particularly based on the structures of several saponins containing hecogenin, neohecogenin, tigogenin, neotigogenin, chlorogenin, or diosgenin as an aglycone moiety that have been demonstrated to be antifungal (1,30,32,37,39).…”

Heterologous expression of Fusarium oxysporum tomatinase in Saccharomyces cerevisiae increases its resistance to saponins and improves ethanol production during the fermentation of Agave tequilana Weber var. azul and Agave salmiana must

“…These results suggest that F. oxysporum tomatinase has the ability to degrade the saponins of agave juice and facilitates the growth of the yeasts. The occurrence of steroidal glycosides (saponins and sapogenins) in several Agavaceae species, especially those belonging to such representative genera as Agave, Dracaena, and Yucca, is well documented (Miyakoshi et al 2000;Jin et al 2004;Mimaki et al 1999;Yokosuka and Mimaki 2007). These glycosides are structurally similar to others steroidal saponins present in others plants.…”