New pregnane glycosides from Caralluma dalzielii

Twenty-seven new pregnane glycosides were isolated from the whole plant of Caralluma dalzielii, and their structures elucidated from extensive 2D NMR analysis as well as ESI-MS experiments. All isolated compounds were tested for their antiproliferative activity on J774.A1, HEK-293, and WEHI-164 cell lines. Moderate to high potency of cytotoxicities were found in almost all tested compounds, confirming the significant cytotoxic activity of pregnane glycosides.     

Spiroorthoester group-containing pregnane glycosides from the root barks of Periploca chrysantha and their inhibitory activities against the proliferation of B and T lymphocytes

Phytochemical investigation of the root barks of Periploca chrysantha D. S. Yao, X. C. Chen et J. W. Ren (Asclepiadaceae) led to the elucidation of four new spiroorthoester group-containing pregnane glycosides (1–4), named periplosides W-Y and 3-O-formyl-periploside F. Their structures were elucidated on the basis of extensive spectroscopic analysis. The four new pregnane glycosides (1–4) were found to exhibit significantly inhibitory activities against the proliferation of B and T lymphocytes and favorable selective index comparable to those of cyclosporin A.     

Desflavasides A-D: Four new tetrasaccharide pregnane glycosides from Desmidorchis flava

Four new pregnane glycosides named desflavasides A-D (1–4) were isolated from the sap of Desmidorchis flava (N.E.Br) Meve & Liede. The structures of all new compounds were elucidated based on 1D and 2D NMR spectroscopic techniques coupled with mass spectromentry (ESIMS and HRESIMS).     

Pregnane glycosides from Hoodia gordonii

Hoodia gordonii is a ‘weight loss’ herb, which has gained popularity in the western countries as an appetite suppressant dietary supplement. Phytochemical study of its aerial parts led to isolation of seven pregnane glycosides (hoodigosides W-Z, hoodistanalosides A-B). Their structures were elucidated by chemical degradation studies and spectroscopic methods, including 1D and 2D NMR and CD spectroscopic methods.     

Structural revision of periplocosides and periperoxides, natural immunosuppressive agents from the genus Periploca

The structures of a series of peroxy function containing pregnane glycosides isolated from Periploca sepium and Periploca forrestii were revised to be orthoester group bearing ones using 2D NMR spectroscopic techniques, as well as chemical transformations and X-ray crystallographic diffraction analysis. The orthoester function appears to be an essential structural feature for immunosuppressive activity.     

New pregnane glycosides from Stelmatocrypton khasianum

Four new pregnane glycosides, stelmatocryptonoside A, B, C, and D (1-4), were isolated from the stems of Stelmatocrypton khasianum. On the basis of chemical and spectral data, the structures of 1-4 were established as 3beta, 16alpha-dihydroxy-pregn-5-en-20-one-16-O-beta-D-glucopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside; 3beta, 20-dihydroxy-pregn-5-en-20-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->2)-beta-D-digitalopyranoside; 3beta, 16alpha-dihydroxy-pregn-5-en-20-one-16-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside; and 3beta, 16alpha-dihydroxy-pregn-5-en-20-one-16-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside. This is the first report of pregnane glycosides with sugar chains linked at C-16 of the aglycone.     

Immunosuppressive pregnane glycosides from Periploca sepium and Periploca forrestii

Nine pregnane glycosides containing peroxy functions in their sugar moieties (1-5 and 11-14), five oligosaccharides (6-10), six pregnane glycosides (15-20), and five cardiac glycosides (21-25) were isolated from the root barks of Periploca sepium Bge. (Asclepiadaceae) and the roots of Periploca forrestii Schltr. (Asclepiadaceae), two traditional Chinese medicines used for the treatment of rheumatoid arthritis. Among them, 1-8 are hitherto unknown. Their structures were characterized on the basis of spectroscopic analyses. In pharmacological testing, compounds 1-5 and 11-14 were found to exhibit inhibitory activity against the proliferation of T lymphocyte in vitro with IC50 values ranging from 0.29microM to 1.97microM, while the other components showed no significant inhibitory activity.     

Verticillosides A–M: Polyoxygenated pregnane glycosides from Asclepias verticillata L.

As part of our ongoing effort to explore the chemical diversity of plants of the United States Midwest region, the isolation and identification of 13 pregnane glycosides named verticillosides A–M from Asclepias verticillata L. are reported. The structures of these compounds were elucidated by various spectroscopic techniques, including 1D and 2D NMR, IR, UV, and HRMS. The cytotoxicity of the isolates was evaluated against paired breast cell lines Hs578T (cancer) and Hs578Bst (normal), however, no significant growth inhibition was observed.     

Pregnane glycosides from Caralluma adscendens var. fimbriata

Eleven novel pregnane glycosides, 2-7 and 9-13, of which four, i.e., 10-13, comprised a new pregnane-type genin exhibiting a hydroxymethylene instead of a Me group at C(19), and the known pregnane glycoside stalagmoside V (8) were isolated from whole plants of Caralluma adscendens var. fimbriata, a native Indian succulent plant. Their structures were elucidated by extensive 2D-NMR spectroscopic studies.     

8,14-Secopregnane glycosides from the aerial parts of Asclepias tuberosa

Twenty pregnane glycosides, tuberoside A₁–L₅, were isolated from the diethyl ether-soluble fraction of the MeOH extract from the aerial parts of Asclepias tuberosa (Asclepiadaceae). The pregnane glycosides were composed of 8,12;8,20-diepoxy-8,14-secopregnane as aglycon, and d-cymarose, d-oleandrose, d-digitoxose and/or d-glucose as the component sugars. Their structures were established using NMR spectroscopic analysis and chemical methodologies.     

8,12;8,20-diepoxy-8,14-secopregnane glycosides from roots of Asclepias tuberosa and their effect on proliferation of human skin fibroblasts

A pregnane glycoside fraction from the roots of Asclepias tuberosa L. caused normal human skin fibroblasts to proliferate. This fraction contained 21 pregnane glycosides whose structures were established using NMR spectroscopic analysis and chemical evidence. The aglycones of most of these compounds were identified as 8,12;8,20-diepoxy-8,14-secopregnanes, such as tuberogenin or 5,6-didehydrotuberogenin, the same aglycones as constituents of the aerial parts of this plant. Some of these compounds also caused proliferation of skin fibroblasts.     

New calogenin glycosides from Hoodia gordonii

Ten new pregnane glycosides (1, 3-11) were isolated from organic extracts of aerial parts of Hoodia gordonii, which is sold as an appetite suppressant herbal supplement. The aglycone was identified as calogenin, based on the spectroscopic data of products obtained upon chemical and enzymatic degradation of parent glycoside. The structures of the glycosides were established by chemical degradation studies and extensive spectroscopic techniques that included one-dimensional and two-dimensional NMR.     

Anti-proliferative and computational studies of two new pregnane glycosides from Desmidorchis flava

Two new pregnane glycosides named desmiflavasides C (1) and D (2) were isolated from the sap of Desmidorchis flava (N.E.Br.) Meve & Liede and have had their structures confirmed from 1D and 2D NMR spectroscopic techniques and mass spectrometry (ESIMS). Further, the effects of desmiflavasides C (1) and D (2) on the proliferation of breast and ovarian cancer cells as well as normal breast epithelial cells in culture were examined. Interestingly, desmiflavasides C (1) and D (2) were able to cause a substantial decline in the viability of cancer cells in a concentration-dependent manner. Moreover, treatment of normal cells with compound 2 resulted in no significant growth inhibition, indicating that its cytotoxicity was selective towards cancer cells. Furthermore, the activity of compound 2 against cancer as well as normal epithelial cells was found to be similar to that of a previously reported pregnane glycoside, nizwaside (3). Molecular docking studies of desmiflavasides C (1) and D (2) and nizwaside (3) were carried out to ascertain if it was possible to predict any important binding orientations required of small molecule drug candidates with suggested protein target molecules for the purposes of being able to predict the affinity and activity to an acceptable degree by such compounds. Desmiflavaside D (2) showed a relatively good binding affinity (−22.4449 kcal/mol) as compared to the other two compounds viz., nizwaside (3) (−20.0319 kcal/mol), and desmiflavaside C (1) (−19.4042 kcal/mol). Docking results of the three pregnane glycosides viz., 1–3 revealed that these ligand molecules can accurately interact with the target protein.     

Acylated pregnane glycosides from Caralluma russeliana

The chloroform extract of the aerial parts of Caralluma russeliana yielded four acylated pregnane glycosides, namely russeliosides E-H, three were found now. The structures of the compounds were elucidated using MS, 1H NMR, 13C NMR, 1H-1H COSY, HMQC, NOESY and HMBC experiments.     

Expeditious and convenient synthesis of pregnanes and its glycosides as potential anti-dyslipidemic and anti-oxidant agents

A series of new pregnane derivatives and its glycosides were synthesized in order to find new 'leads' against some important targets. The 3beta-hydroxy-16alpha-(2-hydroxy ethoxy) pregn-5-en-20-one (5) was synthesized from 3beta-hydroxy-5,16-pregnadiene-20-one (2) by adopting general modified procedure using BF(3):Et(2)O as a catalyst. Reduction of 5, with sodium borohydride yielded 3beta,20beta-dihydroxy-16alpha-(2-hydroxy ethoxy) pregn-5-en (7) as the major isolable product. O-alkylation of the C-20-oxime-pregnadiene (9) with 1,5-dibromopentane yielded 20-(O-5-bromopentyl)-oximino-3beta-hydroxy-pregn-5,16-diene (11). Synthesis of C-16 substituted pregnane glycosides (20) and (21) were accomplished with the imidate method using BF(3):Et(2)O. The synthesis of 4-chlorobenzoate (3) and 2-chlorobenzoate (4), derivatives of 2 were also accomplished. These compounds were evaluated for their anti-dyslipidemic and anti-oxidant activity and amongst them compounds 3 and 7 showed more lipid lowering and anti-oxidant activity.     

Steroidal glycosides from the aerial part of Asclepias incarnata

The aerial part of Asclepias incarnata afforded 34 pregnane glycosides. These were confirmed to have lineolon, isolineolon, ikemagenin, 12-O-nicotinoyllineolon, deacylmetaplexigenin, metaplexigenin, rostratamine, 12-O-acetyllineolon, 15beta-hydroxylineolon and 15beta-hydroxyisolineolon moieties as their aglycones, and 2.6-dideoxyhexopyranose, glucopyranose and allopyranose as the corresponding sugar constituents. Their structures were determined using both spectroscopic and chemical methods.     

Acylated pregnane glycosides from Caralluma tuberculata and their antiparasitic activity

Five pregnane glycosides were isolated from Caralluma tuberculata (1-5), in addition to a known one (russelioside E, 6). The structures of the isolated compounds were elucidated by the analysis of NMR data and FAB-MS experiments. All the isolated compounds were tested for their antimalarial and antitrypanosomal activities as well as their cytotoxicity against human diploid embryonic cell line (MRC5).     

Pregnane glycosides from Cynanchum atratum

Five new pregnane glycosides, cynanosides K-O (1-5) with a 14,15-seco-pregnane-type skeleton as the aglycon, together with five known compounds, cynascyroside C, sublanceoside E(1), sublanceoside I(1), atratoside A and atratoside B, were isolated from the roots of Cynanchum atratum. Their structures were determined on the basis of spectroscopic analysis and chemical evidence.     

Synthesis of Hoodigogenin A, aglycone of natural appetite suppressant glycosteroids extracted from Hoodia gordonii

14β-hydroxy pregnane glycosides extracted from Hoodia gordonii, a succulent plant isolated from Apocynaceae are suggested to have appetite suppressant properties in animals and humans. However, limited reports on biological studies concerning the appetite suppressant properties are available in the open literature. One reason for that is the poor availability of these glycosteroids because H. gordonii is a protected plant and the yield of extraction lies between 0.003% and 0.02%. Starting from 3α,12α-diacetoxy-pregnanone 1, we disclose in this report the synthesis of Hoodigogenin A, the aglycone of the natural 14β-hydroxy pregnane glycosides extracted from H. Gordonii.