New Acylated Presenegenin Saponins from Two Species of Muraltia

Abstract

Six new acylated bisdesmosidic triterpene glycosides 1 ± 6 were isolated from the roots of Muraltia heisteria (L.) DC., as three inseparable mixtures 1/2, 3/4, and 5/6 of the (E)-and (Z)-3,4,5-trimethoxycinnamoyl derivatives. The compound pair 1/2 along with four known saponins were also isolated from the roots of Muraltia satureioides DC. Their structures were elucidated mainly by spectroscopic experiments including 2D-NMR techniques as 3 (5) and its (Z)-isomer 6, respectively.Introduction. ± In a continuing program aiming at the discovery of novel natural products from the family of Polygalaceae, especially the genus Muraltia, we previously reported the isolation and characterization of five new medicagenic acid saponins from the roots of Muraltia ononidifolia [1] and of four new acylated presenegenin glycosides as two inseparable mixtures of the (E)-and (Z)-trimethoxycinnamoyl derivatives from the roots of Muraltia heisteria (L.) DC. [2]. As a result of our continous investigations of less polar saponin fractions of the EtOH extract of the roots of M. heisteria, the six additional new acylated oleanane-type triterpene saponins 1 ± 6 were isolated as three inseparable mixtures 1/2, 3/4, and 5/6 of the (E)-and (Z)-3,4,5-trimethoxycinnamoyl derivatives. Furthermore, we investigated Muraltia satureioides DC., which is a shrub distributed in the Cape region in South Africa [3]. Although, this plant was reported to contain presenegenin glycosides [4], there is no detailed report on its saponins. The compound pair 1/2 together with four known saponins [2] were isolated from the EtOH extract of the roots of M. satureiodes. This paper describes the isolation and structure elucidation of these triterpene glycosides.

Triterpene Saponins from Four Species of the Polygalaceae Family

“…The 3-O-position can be substituted by either an acetyl group or an apiose unit, whereas the 4-O-position was acylated by either an (E)-and (Z)-4-methoxycinnamoyl, or (E)-and (Z)-3,4-dimethoxycinnamoyl group, or by an acetyl group. These results corroborated those previously described for saponins isolated from other Polygalaceae belonging to genera Polygala [1] [5] [6] [9] [10] [14 -18], Carpolobia [3], Muraltia [2] [7], and Securidaca [19], and suggested that this sequence may represent a chemotaxonomic marker for the Polygalaceae family. Plant Material.…”

Two New Antiinflammatory Triterpene Saponins from the Egyptian edicinal Food Black Cumin (Seeds of Nigella sativa)

“…From careful analysis with 1D and 2D NMR data (COSY, TOCSY, HSQC and HMBC), the aglycon part of 1 was revealed to be a triterpene of 3, 23-dihydroxyolean-18-en-28-oic acid, characteristic of six methyl singlets at δ 0.68, 0.81, 0.93, 0.97, 0.99, and 1.01, two diastereotopic protons at δ 3.33 and 3.51 ascribable to a CH 2 OH group and a broad singlet at δ 5.14. The position of the double bond at ∆ 18 (19) was evident from the HMBC correlations of two methyl protons at δ 0.97 and 0.99 with the olefinic carbon at δ 134.0 (C-19) and of the proton at δ 5.14 with two carbons at δ 42.3 (C-13) and 49.9 (C-17). The linkage of the CH2OH and the carbonyl carbon groups to two quaternary carbons at C-4 and C-17, respectively, was also secured by the HMBC correlations between two methylene protons at δ 3.33 and 3.51 and the carbon at δ 44.1 (C-4) and between the proton at δ 2.02 (H-16) and the carbonyl carbon at δ 177.0 (C-28).…”

“…[15][16][17] These observations prompted us to continue in our research aimed at finding biologically active and/or novel saponins from plant origin. [18][19][20][21][22][23] Recently, we investigated the suppression effect of the production of cytokine interleukin (IL)-6 in human mast cell (HMC-1) on the methanolic extract of the seeds of N. sativa, which may contribute to the treatment of asthmatic inflammation. Through bioactivity and 1 H NMR monitoring guided fractionation of the methanolic extract of the seeds of N. sativa, six triterpene glycosides were isolated composed of two new compounds, sativosides A (1) and B (2) and four known ones.…”

Triterpene Saponins from Polygalaceae

“…From M. heisteria, five pairs of presenegenin glycosides 20/21-28/29 have been isolated. Three of them are new and are also found in M. satureioides (Elbandy et al, 2002b(Elbandy et al, , 2004. All compounds contain one b-D-glucopyranosyl unit at C-3 and one glycosidic chain at C-28 of three to six sugars, eventually acylated.…”

“…Most of the saponins characterized in Muraltia (Elbandy et al, 2002b(Elbandy et al, , 2004, Polygala (Sakuma andShoji, 1981a, 1981b;Miyase et al, 1995;Yoshikawa et al, 1995a, b;Zhang et al, 1996aZhang et al, , 1996bZhang et al, , 1998Desbe`ne et al, 1999;Haddad et al, 2003;Mitaine-Offer et al, 2003), Carpolobia by either E/Z-4-methoxy-, or E/Z-3,4-dimethoxy-, or E/Z-3,4,5-trimethoxycinnamoyl groups, or by one acetyl group.…”