Isolation of Nor-secofriedelanes from the Sedative Extracts of Galphimia glauca

Abstract

Preparative-scale recycling HPLC was used for the complete resolution of a complex mixture of nor-secofriedelanes into five major peaks (I-V) from the sedative methanolic extracts prepared from the aerial parts of Galphimia glauca. Argentation chromatography was used to show peaks I, II, IV, and V to be mixtures of isomers around the E-ring double bond, represented by the endocyclic C-20, C-21 double-bond isomers, galphimines A (3), B (1), D (4), and E (2), and the C-20, C-29 exocyclic forms, galphimines F-I (5-8). Galphimine C (9), isolated from peak III, corresponded to the C-19, C-20 double-bond isomer of the previously known major sedative constituent galphimine B. The characterization of all the new triterpenes (3-9) was performed primarily by high-field NMR spectroscopy. Comparison between experimental and calculated (1)H-(1)H vicinal coupling constants and the analysis of molecular mechanics structures revealed that the ring B of these compounds exists in a boatlike conformation. The absolute configuration for the stereogenic carbinol center at C-4 was established by the application of the Mosher ester derivatization technique carried out in NMR tubes.

Norsecofriedelanes as Spasmolytics, Advances of Structure-Activity Relationships

“…This was separated by preparative RP-HPLC to afford the compounds 1 ± 5. The mass and 1 H-and 13 C-NMR spectral data of these compounds resembled closely those already reported for galphimine E (3), galphimine G (4) and galphimine A (5), respectively [10]. Although the optical activity, mass and 1 H-and 13 C-NMR spectral data of compound 1, as isolated in this work, were very similar to those reported for galphimine B, its melting point was very different [263 ± 265 8C (present work) vs. 149 ± 152 8C (from the literature)].…”

“…The identity of this compound as galphimine B was confirmed by an X-ray analysis (data not shown) that was performed with suitable crystals obtained by slow evaporation of the methylene chloride/ acetone (95 : 5, v/v) suspension. Recently, two ring-E double bond isomers of galphimine B [galphimines F (6) and C (7)] from a wild population of G. glauca have been described [10]. In our present study, we did not find these isomers.…”

“…Recent studies demonstrated that the effect produced by galphimine B is not related to the GABAergic system because it was found to inhibit selectively the activity of dopaminergic neurons from the ventral tegmental area in rats [6], [7]. From Galphimia glauca, compounds inhibiting bronchial spasm induced by allergens have been isolated [8] as well as other interesting triterpenes with possible biological activities [9], [10].…”

A comparison on the metabolic profiling of the Mexican anxiolytic and sedative plant Galphimia glauca four years later

“…By extensive phytochemical and pharmacological analysis conducted in specimens growing in the state of Guanajuato (GM), a family of nine bioactive nor-secofriedelanes designated as galphimines, was identified (Cardoso-Taketa et al, 2004). The sedative activity of galphimines has been demonstrated using in vitro models (Prieto- Gómez et al, 2003) and the anxiolytic action of galphimines A, B and E were documented in mice (Herrera-Ruiz et al, 2006).…”

DNA barcoding of the Mexican sedative and anxiolytic plant Galphimia glauca

“…This plant is a popular herbal medicine which has been used as a tranquilizer in the treatment of nervous system disorders since prehispanic times (Estrada, 1985). A family of nine bioactive nor -secofriedelanes with sedative and anxiolytic properties, named galphimines, were identified in specimens of Galphimiaglauca growing in the locality of Doctor Mora, Guanajuato (Cardoso-Taketa et al, 2004). The sedative activity and the anxiolytic action of galphimines have been documented using in vitro models (Prieto-Gómez et al, 2003; Herrera-Ruiz et al, 2006).…”