Ornithosaponins A-D, four new polyoxygenated steroidal glycosides from the bulbs of Ornithogalumthyrsoides

By analyzing the steroidal glycoside content of fresh bulbs of Ornithogalum thyrsoides (Liliaceae), we were able to isolate four new polyoxygenated steroidal glycosides, which we named ornithosaponins A-D (1-4). The structures of 1-4 were elucidated on the basis of extensive spectroscopic analysis, including that of 2D NMR data, and the results of acidic or alkaline hydrolysis. The aglycone structure of 1-4 has not been previously reported. It is also notable that ornithosaponins B-D (2-4) have been found to contain 6-deoxy-beta-D-gulopyranose as a sugar component, which is rarely encountered in plant glycosides.     

Glycopentanolones A-D,four new geranylated quinolone alkaloids from Glycosmis pentaphylla

The ethanolic extract obtained from the stems of Glycosmis pentaphylla was found to suppress antigen-mediated degranulation of rat basophilic leukemia (RBL-2H3) cells. Four new geranylated 2-quinolone alkaloids, named glycopentanolones A–D (1–4), and 12 known metabolites (5–16) were isolated from the ethanolic extract from the stems of G. pentaphylla using bioassay-guided fractionation. Their structures were elucidated by a combination of 1D and 2D NMR, and HRESI-MS. The inhibitory effects of the isolated constituents on β-hexosaminidase release from RBL-2H3 cells were examined, and compounds 1, 5, 8 and 11 exhibited potent inhibitory activity with IC₅₀ values between 0.05 and 4.28 μM.     

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).     

Five new C21 steroidal glycosides from Periploca sepium

Five new C₂₁ steroidal glycosides, named periseosides A-E (1-5), along with six known analogues, were isolated from the root barks of Periploca sepium. Their structures were elucidated on the basis of spectroscopic analysis and chemical evidence. All compounds were evaluated for their immunosuppressive activities.     

Six new C21 steroidal glycosides from Asclepias curassavica L

Six new C₂₁ steroidal glycosides, named curassavosides A–F (3–8), were obtained from the aerial parts of Asclepias curassavica (Asclepiadaceae), along with two known oxypregnanes, 12-O-benzoyldeacylmetaplexigenin (1) and 12-O-benzoylsarcostin (2). By spectroscopic methods, the structures of the six new compounds were determined as 12-O-benzoyldeacylmetaplexigenin 3-O-β-d-oleandropyranosyl-(1 → 4)-β-d-digitoxopyranoside (3), 12-O-benzoylsarcostin 3-O-β-d-oleandropyranosyl-(1 → 4)-β-d-digitoxopyranoside (4), sarcostin 3-O-β-d-oleandropyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-oleandropyranosyl-(1 → 4)-β-d-digitoxopyranoside (5), sarcostin 3-O-β-d-oleandropyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-digitoxopyranoside (6), 12-O-benzoyldeacylmetaplexigenin 3-O-β-d-glucopyranosyl-(1 → 4)-β-d-oleandropyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-oleandropyranosyl-(1 → 4)-β-d-digitoxopyranoside (7), and 12-O-benzoylsarcostin 3-O-β-d-glucopyranosyl-(1 → 4)-β-d-oleandropyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-oleandropyranosyl-(1 → 4)-β-d-digitoxopyranoside (8), respectively. All compounds (1–8) were tested for in vitro cytotoxicity; only compound 3 showed weak inhibitory activity against Raji and AGZY cell lines.     

Seven new steroidal glycosides from the roots of Cynanchum forrestii

Seven new steroidal glycosides, cynaforrosides K (1), L (2), M (3), N (4), and Q (7), based on a 13,14:14,15-disecopregnane-type aglycone, and cynaforrosides O (5) and P (6) with a 14,15-secopregnane-type aglycone, were isolated from the 95% ethanol extract of the roots of Cynanchum forrestii Schlechter. The structures of new compounds were determined on the basis of spectroscopic and chemical evidence. The sugar units of cynaforrosides K-P contained two moieties of glucoses with the mode of 1-->4 linkage and those of cynaforrosides K-O contained six moieties of sugars.     

Two new polyhydroxylated steroidal glycosides from Paris polyphylla var. yunnanensis

Chemical investigation of Paris polyphylla smith var. yunnanensis afforded two new polyhydroxylated steroidal glycosides, named Parisyunnanosides K and L (1–2), together with nine known ones. The chemical structures of the new compounds were elucidated by 1D, 2D NMR and HR-ESI-MS techniques, together with chemical methods. Parisyunnanosides K and L (1–2) are rare C₂₇ steroidal glycosides with two double bonds located at C-5, 6 and C-25, 26 of the aglycone, respectively. The cytotoxic activities of the isolated compounds were evaluated against Caco-2 cells by CCK-8 assay. Among them, compounds 5–11 exhibited potent cytotoxic activity with IC₅₀ values ranging from 1.10 to 14.14 μM compared with the positive control oxaliplatin (1.38 μM).     

Four new steroidal glycosides from Solanum torvum and their cytotoxic activities

Two novel C-22 steroidal lactone saponins, namely solanolactosides A, B (1, 2) and two new spirostanol glycosides, namely torvosides M, N (3, 4) were isolated from ethanol extract of aerial parts of Solanum torvum. Their structures were characterized as solanolide 6-O-[α-l-rhamnopyranosyl-(1 → 3)-O-β-d-quinovopyranoside] (1), solanolide 6-O-[β-d-xylopyranosyl-(1 → 3)-O-β-d-quinovopyranoside] (2), yamogenin 3-O-[β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside] (3) and neochlorogenin 3-O-[β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside] (4) on the basis of spectroscopic analysis. The cytotoxicities of the saponins (1-4) were evaluated in vitro against a panel of human cancer cell lines. Compounds 3 and 4 showed significant cytotoxic activity with the cell lines.     

Four new immunomodulating steroidal glycosides from the stems of Stephanotis mucronata

Four new C-21 steroidal glycosides, mucronatosides E (1), F (2), G (3), and H (4), were isolated from the stems of Stephanotis mucronata. Two of them had the rare aglycone with a double bond between C-6 and C-7. Their structures were elucidated on the basis of spectroscopic data and chemical evidence. These isolated compounds were assayed for their immunological activities in vitro against concanavalin A (Con A)- and lipopolysaccharide (LPS)-induced proliferation of mice splenocytes. Compounds 2 and 4 showed immunosuppressive activities in a dose-dependent manner, while compounds 1 and 3 possessed immunoenhancing activities.     

Eight new C-21 steroidal glycosides from Dregea sinensis var. corrugata

Eight new steroidal glycosides, dresiosides were isolated from the stems of Dregea sinensis var. corrugate and their structures were deduced on the basis of chemical and spectral evidence. The sugar units of dresiosides were determined as deoxysugars after hydrolysis and isolation from natural glycosides. The absolute configurations of deoxysugars were determined as D on the basis of their optical rotation values in comparison with appropriate standards.     

Five new C21 steroidal glycosides from Cynanchum komarovii Al.Iljinski

Five new C21 steroidal glycosides, namely, komarosides D (1), E (2), F (3), G (4), and H (5), along with two known C21 steroidal glycosides cynatratoside E (6) and hancoside A (7), were isolated from the ethanol extract of the roots of Cynanchum komarovii Al.Iljinski (Asclepiadaceae). Their structures were determined by physiochemical and spectroscopic analysis. Among these glycosides, five had an aberrant 13,14:14,15-disecopregnane-type skeleton, and the other two had normal four-ring C21 steroid skeletons. The existence of more than one type of C21 steroid skeleton in one species is rare in the plants of the family Asclepiadaceae, and this has chemotaxonomic significance for this species.     

C21 steroidal glycosides from Hemidesmus indicus

Two novel pregnane glycosides, denicunine (1) and heminine (4), have been isolated from the dried stem of Hemidesmus indicus R.Br. (family: Asclepiadaceae). Chemical transformations and spectroscopic evidence viz: 1H and 13C NMR spectroscopy and FABMS are consistent with the structures calogenin 3-O-3-O-methyl-beta-D-fucopyranosyl-(1-->4)-O-beta-D-oleandropyranosi de and calogenin 3-O-beta-D-cymaropyranosyl-(1-->4)-O-beta-D-digitoxopyranoside+ ++, respectively.     

Bioactive steroidal alkaloid glycosides from Solanum aculeastrum.

Solanum aculeastrum Dunal was investigated for the presence of molluscicidal compounds. This led to the isolation of solaculine A, from the root bark in addition to known steroidal alkaloids; solamargine and beta-solamarine from the berries. The structures were elucidated by spectroscopic techniques. Molluscicidal activity of the aqueous extracts of the berries and root bark, and the isolated compounds were investigated.     

New steroidal glycosides from rhizomes of Clintonia udensis

A total of 10 steroidal glycosides, together with three new spirostanol glycosides (6-8), a new furostanol glycoside (9), and a new cholestane glycoside (10), were isolated from the rhizomes of Clintonia udensis (Liliaceae). The structures of the new compounds were determined on the basis of extensive spectroscopic analyses, including 2-D nuclear magnetic resonance (NMR) data, and of hydrolytic cleavage followed by chromatographic or spectroscopic analyses. The isolated glycosides were evaluated for their cytotoxic activity against HL-60 leukemia cells. Spirostanol glycosides 1 and 2, and furostanol glycoside 4 showed cytotoxic activity with IC(50) values of 3.2+/-0.02, 2.2+/-0.12, and 2.2+/-0.06 microg/ml, respectively. Neither the spirostanol and furostanol saponins with a hydroxy group at C-1 (6 and 9) and C-12 (7 and 8) nor cholestane glycosides (5 and 10) exhibited apparent cytotoxic activity at a sample concentration of 10 microg/ml.     

New glycosides of the campesterol derivative from the rhizomes of Tacca chantrieri

Seven new glycosides of the campesterol derivative (24R,25S)-ergost-5-ene-3beta,26-diol (1-7) were isolated from the rhizomes of Tacca chantrieri (Taccaceae). Their structures were determined by extensive spectroscopic analysis, including 2D NMR data, and a few chemical transformations.     

Macrocarpins A-D, new cytotoxic nor-triterpenes from Maytenus macrocarpa

Macrocarpins A (1), B (2), C (3) and D (4), four new nor-triterpenes, have been isolated from the roots of Maytenus macrocarpa. The structures were established by spectroscopic examinations. Natural compounds 1, 2, 4 and the acetyl derivative 1a are cytotoxic against four tumoral cell lines with IC50 values ranging between 0.4 and 5.2 microM.     

Seco-pregnane steroidal glycosides from the roots of Cynanchum stauntonii

By analyzing the steroidal content of the roots of Cynanchum stauntonii, we isolated three new C₂₁ steroidal glycosides named cynastauosides A-C (1–3), all of which shared the 14,15-secopregnane-type skeleton. Their structures were determined on the basis of detailed spectroscopic analysis, including 2D NMR and qualitative chemical tests. Anti-inflammatory activities of compounds 1–3 were evaluated in vitro, with 2 and 3 inhibiting nitric oxide production in C57bl/6j mouse peritoneal macrophages by 17.0% and 6.9% of inhibition rate at a concentration of 10 μM, respectively.     

Tropolactones A-D, four meroterpenoids from a marine-derived fungus of the genus Aspergillus

Four cytotoxic meroterpenoids, tropolactones A-D, were isolated from the whole broth extract of a marine-derived fungus of the genus Aspergillus. The structures of the meroterpenoids were established through a variety of two-dimensional NMR techniques. The absolute configuration of tropolactone A was determined using the modified Mosher method. Tropolactones A-C contain an interesting substituted 2,4,6-cycloheptatriene (tropone) ring, which presumably arises through an oxidative ring expansion from tropolactone D. Tropolactones A, B and C showed in vitro cytotoxicity against human colon carcinoma (HCT-116) with IC50 values of 13.2, 10.9 and 13.9 microg/mL.     

Four new C-21 steroidal glycosides from the roots of Stephanotis mucronata and their immunological activities

Four new C-21 steroidal glycoside, stemucronatosides D (1), E (2), F (3), and G (4) were isolated from the roots of Stephanotis mucronata. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods including one-dimensional and two-dimensional NMR. These isolated compounds were assayed for their immunological activities in vitro against concanavalin A (Con A)- and lipopolysaccharide (LPS)-induced proliferation of mice splenocytes. Compounds 1, 2, and 4 showed immunosuppressive activities in a dose-dependent manner, while compound 3 showed immunomodulating activities.     

Elucidation of excogallochaols A-D, four unusual diterpenoids from the Chinese mangrove Excoecaria agallocha

Diterpenoids, excoagallochaols A-D (1-4), with an unprecedented skeleton, were isolated from the ethyl acetate extract of the stems and leaves of the mangrove Excoecaria agallocha L. The structures of these metabolites were elucidated on the basis of detailed analysis of their spectroscopic data and by comparison with those of related compounds reported in literature.