New Alkaloids and Steroids from Hydranth of Goniopora columna Corals and Their Inhibiting Lung Cancer Cell Activities.

A new alkaloids, aplysingoniopora A (1), and new configuration pregnane type steroid compound, 9,17-α-pregn-1,4,20-en-3-one (2), and two known pregnane type steroid compounds (3 and 4) were isolated from hydranth of Goniopora columna corals. The compounds structures and absolute configurations were determined by extensive spectroscopic analysis, MS data, single-crystal X-ray diffraction analysis and quantum chemical calculation. The anticancer effect of the compounds were explored in human non-small-cell lung cancer (NSCLC) A549 cell lines. As the results, the compound 3 and 4 induces toxicity and has proliferation inhibitory effects on A549 cells (IC50=58.99 µM and 58.77 µM, respectively) in vitro.

Identification and Cytotoxic Evaluation of Pregnane Saponins from the Twigs and Leaves of Dregea volubilis.

Four new polyhydroxy pregnane glycosides, named volubilosides G-K (3, 5-7), along with three known secondary metabolites, dregeoside Da1 (1), dregeoside Ka1 (2), and volubiloside E (4) were isolated from the twigs and leaves of Dregea volubilis (DV). The chemical structures of these compounds (1-7) were elucidated using spectroscopic techniques (1D and 2D NMR and HR-ESI-MS analyses) and compared with those in the published literature. Compounds (1-7) were evaluated for cytotoxicity against eight cancer cell lines (MB49, K562, MKN-7, HT29, A549, MCF-7, MDA-MB-231, and HepG2), revealing varying levels of cytotoxic effects with IC50 values ranging from 4.29 to 21.05 µM. The results indicated that compounds 1-7 may serve as potential lead compounds for the discovery and development of novel anti-cancer drugs.

Pregnane steroid glycosides with multidrug resistance reversal activity from the stems of Marsdenia tenacissima.

Eighteen previously unreported pregnane glycosides, namely marsdenosides S1-S18, along with 15 known analogues, have been isolated from the stems of Marsdenia tenacissima. The structures of the undescribed compounds were elucidated by spectroscopic means, and their absolute configurations were established on the basis of time-dependent density functional theory (TD-DFT) based electronic circular dichroism (ECD) calculation, X-ray crystallography and acid hydrolysis. All the isolates were evaluated for their chemo-reversal ability against P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in MCF-7/ADR cell line, and nine ones displayed moderate MDR reversal activity with reversal folds in the range of 2.45-9.01. The most active 12-O-acetyl-20-O-benzoyl-(14,17,18-orthoacetate)-dihydrosarcostin-3-O-ß-d-thevetopyranosyl-(1 â†’ 4)-O-ß-d-oleandropyranosyl-(1 â†’ 4)-O-ß-d-cymaropyranoside increased the sensitivity of MCF-7/ADR cell to adriamycin comparably to the reference drug verapamil (RF = 8.93).

Pregnane steroids and steroid glycosides with multidrug resistance reversal activity from Marsdenia tenacissima.

Twenty compounds comprising four pregnane steroids (2-4 & 20) and 16 pregnane glycosides (1 & 5-19) have been obtained from the ethanol extract of the roots of a Dai ethnological herb, Marsdenia tenacissima. Their structures were characterized on the basis of comprehensive spectroscopic analyses with 17 ones (1-17) being reported for the first time, including the rare cases (2 & 3) of free C21 steroids with 17α-acetyl substitution, compounds 4-7 bearing an unusual 14α-OH, and the first examples with simultaneous 14α-OH/17α-acetyl substitution (7) and glycosylation at C-12 position (10 & 11). An empirical rule for the identification of C-17 configuration, in C21 steroids incorporating the marsdenin constitution structure, was also proposed. All the isolates, along with an array of previously reported analogues in our compound library, were screened for their chemo-reversal ability against P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in MCF-7/ADR cell line, and six compounds exhibited moderate MDR reversal activity with reversal folds ranging from 1.92 to 4.44.

Two new pregnane glycosides from the root of Cynanchum auriculatum.

Two new pregnane glycosides (1 and 2), together with four known ones (3- 6), were isolated from the roots of Cynanchum auriculatum Royle ex Wight (Asclepiadaceae). On the basis of detailed spectroscopic analysis and chemical method, the structures of new compounds were characterized to be metaplexigenin 3-O-ß-D-cymaropyranosyl- (1→4)-α-L-diginopyranosyl-(1→4)-ß-D-cymaropyranoside (1), metaplexigenin 3-O-α-L-diginopyranosyl-(1→4)-ß-D-cymaropyranoside (2). All the isolated compounds (1-6) were tested for their in vitro inhibitory activity against the growth of human colon cancer cell lines HCT-116. Compounds 5 and 6 showed significant cytoxicities with IC50 values of 43.58 µM and 52.21 µM.

Cytotoxic steroids from the stems of Strophanthus divaricatus.

Phytochemical investigation on the stems of Strophanthus divaricatus led to the isolation of four undescribed cardiac glycosides and one undescribed C21 pregnane, together with eleven known steroids. Their structures were elucidated by a comprehensive analysis of HRESIMS, 1D and 2D NMR spectra. The absolute configuration of 16 was determined by comparison of the experimental and computed ECD spectra. Compounds 1-13 and 15 displayed potent to significant cytotoxicity against human cancer cell lines K562, SGC-7901, A549 and HeLa with IC50 values of 0.02-16.08, 0.04-23.13, 0.06-22.31 and 0.06-15.13 µM, respectively.

seco-Pregnane Glycosides from Australian Caustic Vine (Cynanchum viminale subsp. australe).

Cynanchum viminale subsp. australe, more commonly known as caustic vine, is a leafless succulent that grows in the northern arid zone of Australia. Toxicity toward livestock has been reported for this species, along with use in traditional medicine and its potential anticancer activity. Disclosed herein are novel seco-pregnane aglycones cynavimigenin A (5) and cynaviminoside A (6), together with new pregnane glycosides cynaviminoside B (7) and cynavimigenin B (8). Cynavimigenin B (8) contains an unprecedented 7-oxobicyclo[2.2.1]heptane moiety in the seco-pregnane series, likely arising from a pinacol-type rearrangement. Interestingly, these isolates displayed only limited cytotoxicity in cancer and normal human cell lines, in addition to low activity against acetylcholinesterase and Sarcoptes scabiei bioassays, suggesting that 5-8 are not associated with the reported toxicity of this plant species.

Alkaloid Derivative (Z)-3ß-Ethylamino-Pregn-17(20)-en Inhibits Triple-Negative Breast Cancer Metastasis and Angiogenesis by Targeting HSP90α.

Metastasis is an important cause of cancer-related death. Previous studies in our laboratory found that pregnane alkaloids from Pachysandra terminalis had antimetastatic activity against breast cancer cells. In the current study, we demonstrated that treatment with one of the alkaloid derivatives, (Z)-3ß-ethylamino-pregn-17(20)-en (1), led to the downregulation of the HIF-1α/VEGF/VEGFR2 pathway, suppressed the phosphorylation of downstream molecules Akt, mTOR, FAK, and inhibited breast cancer metastasis and angiogenesis both in vitro and in vivo. Furthermore, the antimetastasis and antiangiogenesis effects of 1 treatment (40 mg/kg) were more effective than that of Sorafenib (50 mg/kg). Surface plasmon resonance (SPR) analysis was performed and the result suggested that HSP90α was a direct target of 1. Taken together, our results suggested that compound 1 might represent a candidate antitumor agent for metastatic breast cancer.

Russelioside A, a Pregnane Glycoside from Caralluma tuberculate, Inhibits Cell-Intrinsic NF-κB Activity and Metastatic Ability of Breast Cancer Cells.

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a potential target for inflammatory-breast cancer treatment as it participates in its pathogenesis, such as tumor initiation, progression, survival, metastasis, and recurrence. In this study, we aimed to discover a novel anti-cancer treatment from natural products by targeting NF-κB activity. Using the 4T1-NFκB-luciferase reporter cell line, we tested three pregnane glycosides extracted from the herb Caralluma tuberculata and discovered that Russelioside A markedly suppressed NF-κB activity in breast cancer. Russelioside A inhibited NF-κB (p65) transcriptional activity and its phosphorylation. Following NF-κB inhibition, Russelioside A exerted anti-proliferative and anti-metastatic effects in breast cancer cells in vitro. Moreover, it inhibited the NF-κB constitutive expression of downstream pathways, such as VEGF-b, MMP-9, and IL-6 in 4T1 cells. In addition, it reduced the metastatic capacity in a 4T1 breast cancer model in vivo. Collectively, our conclusions reveal that Russelioside A is an attractive natural compound for treating triple-negative breast cancer growth and metastasis through regulating NF-κB activation.

New Pregnane Glycosides from Mandevilla dardanoi and Their Anti-Inflammatory Activity.

Mandevilla Lindl. is an important genus of the Apocynaceae family, not only as ornamental plants but also for its medicinal uses. In Brazil, Mandevilla species are indicated to treat asthma and skin infections, their anti-inflammatory potential and wound healing properties are also reported in the literature. Concerning their chemical composition, this group of plants is a conspicuous producer of pregnane glycosides. Mandevilla dardanoi is an endemic species from the Brazilian semiarid region not studied by any phytochemical methods. In view of the medicinal potential of Mandevilla species, this study aimed to isolate new pregnane glycosides from M. dardanoi. To achieve this main goal, modern chromatography techniques were employed. Five new pregnane glycosides, dardanols A-E, were isolated from the roots of M. dardanoi by HPLC. Their structures were determined using extensive 1D and 2D-NMR and mass spectrometry (MSn and HRESIMS) data. The cytotoxicity and the anti-inflammatory potential of these compounds were evaluated. The first was evaluated by measuring proinflammatory cytokines and nitric oxide production by stimulated macrophages. Dardanols were able to inhibit the production of nitric oxide and reduce IL-1ß and TNF-α. The current work demonstrates the chemodiversity of Brazilian semiarid species and contributes to amplifying knowledge about the biological potential of the Mandevilla genus.

Twelve New Seco-Pregnane Glycosides from Cynanchum taihangense.

For our interest in the potential biologically active and structurally unique steroidal glycosides, continued phytochemical investigation of Cynanchum taihangense was carried out; twelve new seco-pregnane glycosides, cynataihosides I-L (1-4), M-T (7-14), and two known glycosides, glaucoside A (5) and atratcynoside F (6), were isolated from the 95% ethanol extract of Cynanchum taihangense. Two new aglycones were found among compounds 10, 11, 13, and 14. The structures of the glycosides were elucidated based on 1D and 2D NMR spectroscopic data, HR-ESI-MS analysis, and chemical evidence. The cytotoxicity of compounds against three human tumor cell lines (HL-60, THP-1, and PC-3) were evaluated by MTT assay. Compound 11 displayed significant cytotoxicity against THP-1 and PC-3 cell line with IC50 values of 5.08 and 22.75 µm, respectively. Compounds 3 and 14 exhibited moderate and selective cytotoxicity on HL-60 and THP-1 with IC50 values of 17.78 and 16.02 µm, respectively.

Pregnane-Oximino-Alkyl-Amino-Ether Compound as a Novel Class of TGR5 Receptor Agonist Exhibiting Antidiabetic and Anti-Dyslipidemic Activities.

INTRODUCTION: The present study deals with the synthesis of pregnane-oximino-amino-alkyl-ethers and their evaluation for antidiabetic and anti-dyslipidemic activities in validated animal and cell culture models. METHODS: The effect on glucose tolerance was measured in sucrose-loaded rats; antidiabetic activity was evaluated in streptozotocin (STZ)-induced diabetic rats and genetically diabetic db/db mice; the anti-dyslipidemic effect was characterized in high-fructose, high-fat diet (HFD)-fed dyslipidemic hamsters. The effect on glucose production and glucose utilization was analyzed in HepG2 liver and L6 skeletal muscle cells, respectively. RESULTS: From the synthesized molecules, pregnane-oximino-amino-alkyl-ether (compound 14b) improved glucose clearance in sucrose-loaded rats and exerted antihyperglycemic activity on STZ-induced diabetic rats. Further evaluation in genetically diabetic db/db mice showed temporal decrease in blood glucose, and improvement in glucose tolerance and lipid parameters, associated with mild improvement in the serum insulin level. Moreover, compound 14b treatment displayed an anti-dyslipidemic effect characterized by significant improvement in altered lipid parameters of the high-fructose, HFD-fed dyslipidemic hamster model. In vitro analysis in the cellular system suggested that compound 14b decreased glucose production in liver cells and stimulated glucose utilization in skeletal muscle cells. These beneficial effects of compound 14b were associated with the activation of the G-protein-coupled bile acid receptor TGR5. CONCLUSION: Compound 14b exhibits antidiabetic and anti-dyslipidemic activities through activating the TGR5 receptor system and can be developed as a lead for the management of type II diabetes and related metabolic complications.

Pregnane glycosides from Adonis amurensis and their bioactivity.

Seven undescribed pregnane glycosides named amurensides A-G and two known aglycones were isolated from the whole herb of Adonis amurensis Regel & Radde. Their structures were established based on 1D and 2D NMR spectroscopic analyses, high-resolution mass spectrometry, and acid hydrolysis. The cytotoxicity of all compounds against three tumor cell lines (HepG2, Caco-2, and A549) were evaluated. Among them, amurensides A-C and E showed moderate inhibitory effects on the growth of HepG2 cells, with IC50 values ranging from 15.6 to 48.7 µM (sorafenib, 7.5 ± 1.9 µM). Amurensides A、D and F displayed inhibitory effects on the growth of A549 cells with IC50 values of 18.8 ± 1.2, 12.4 ± 0.6, and 30.4 ± 0.1 µM (cis-platinum, 6.1 ± 0.1 µM), respectively.

Pregnane Steroids from the Leaves of Melia Azedarach and Apoptotic Activity against T47D Cells.

OBJECTIVE: Nature has provided us with many pharmaceutical resources so far. Breast cancer shows an increasing trend in the world for the last decade and becomes one of five leading causes of death. Among the plants, Melia azedarach L. has been used widely in traditional medicine for many ailments including breast cancer. Following our previous findings that the ethyl acetate fraction was the most active cytotoxic fraction against T47D cells, we aimed to isolate the cytotoxic compounds and further elucidate their apoptotic mechanisms. METHODS: The compounds were isolated through a series of chromatography with cytotoxicity evaluations. Identification of the isolated compounds was achieved by intensive spectroscopic analysis such as NMR, MS, and IR spectra. Cytotoxicity was evaluated by MTT method using doxorubicin as a reference compound. The expression of apoptosis-related factors was quantified by flow cytometry and immunocytochemistry. RESULTS: Two isomers of pregnane steroids with molecular weight 330.2087 (C21H30O3) were isolated from the EtOAc extract. Spectroscopic analysis revealed the structures as 17-ethylene-3,4-dihydroxy-14-methyl-18-norandrostene-16-one (1) and 17-ethylene-3,4-dihydroxy-5-pregnene-16-one (2), respectively. These compounds showed moderate cytotoxicity (IC50 172.9 and 62.2 µg/mL, respectively) comparable to doxorubicin (IC50 3.08 µg/mL). The execution of apoptosis may be related to the increase of the ratio of BAX/bcl-2 of the cells.  Conclusion: The EtOAc fraction of Melia azedarach L. leaves and the isolated 5-pregnene-16-one steroids are promising reagents for breast cancer treatment by introducing apoptosis to tumor cells. However, further researches are required to highlight its safety and usage in vivo.
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C21, C22 pregnane glycosides and cytotoxic C27 spriostanol steroids from Asparagus cochinchinesis.

A preliminary chemical investigation on 70% MeOH extract of the roots of Asparagus cochinchinensis resulted in the isolation of nine steroids. These isolates comprised of four new C21 (1-4) and one new pregnane (5) glycosides, and four known C27 (6-9) spirostanol steroids. Their structures were identified via analysis of the spectroscopic data and the results of hydrolytic cleavage. The cytotoxic activities of the compounds were tested toward the human tumor cell line Hela (cervical cancer), and compounds 7 and 8 displayed moderate activity with IC50 values of 35.5 and 39.6 µM, respectively.

Palmitoylation Controls NMDA Receptor Function and Steroid Sensitivity.

NMDARs are ligand-gated ion channels that cause an influx of Na+ and Ca2+ into postsynaptic neurons. The resulting intracellular Ca2+ transient triggers synaptic plasticity. When prolonged, it may induce excitotoxicity, but it may also activate negative feedback to control the activity of NMDARs. Here, we report that a transient rise in intracellular Ca2+ (Ca2+ challenge) increases the sensitivity of NMDARs but not AMPARs/kainate receptors to the endogenous inhibitory neurosteroid 20-oxo-5ß-pregnan-3α-yl 3-sulfate and to its synthetic analogs, such as 20-oxo-5ß-pregnan-3α-yl 3-hemipimelate (PAhPim). In cultured hippocampal neurons, 30 µm PAhPim had virtually no effect on NMDAR responses; however, following the Ca2+ challenge, it inhibited the responses by 62%; similarly, the Ca2+ challenge induced a 3.7-fold decrease in the steroid IC50 on recombinant GluN1/GluN2B receptors. The increase in the NMDAR sensitivity to PAhPim was dependent on three cysteines (C849, C854, and C871) located in the carboxy-terminal domain of the GluN2B subunit, previously identified to be palmitoylated (Hayashi et al., 2009). Our experiments suggested that the Ca2+ challenge induced receptor depalmitoylation, and single-channel analysis revealed that this was accompanied by a 55% reduction in the probability of channel opening. Results of in silico modeling indicate that receptor palmitoylation promotes anchoring of the GluN2B subunit carboxy-terminal domain to the plasma membrane and facilitates channel opening. Depalmitoylation-induced changes in the NMDAR pharmacology explain the neuroprotective effect of PAhPim on NMDA-induced excitotoxicity. We propose that palmitoylation-dependent changes in the NMDAR sensitivity to steroids serve as an acute endogenous mechanism that controls NMDAR activity.SIGNIFICANCE STATEMENT There is considerable interest in negative allosteric modulators of NMDARs that could compensate for receptor overactivation by glutamate or de novo gain-of-function mutations in neurodevelopmental disorders. By a combination of electrophysiological, pharmacological, and computational techniques we describe a novel feedback mechanism regulating NMDAR activity. We find that a transient rise in intracellular Ca2+ increases NMDAR sensitivity to inhibitory neurosteroids in a process dependent on GluN2B subunit depalmitoylation. These results improve our understanding of the molecular mechanisms of steroid action at the NMDAR and indeed of the basic properties of this important glutamate-gated ion channel and may aid in the development of therapeutics for treating neurologic and psychiatric diseases related to overactivation of NMDARs without affecting normal physiological functions.

Two new pregnane steroidal glycosides from Cynanchum taihangense.

As our ongoing chemical investigation, two new pregnane steroidal glycosides, cynataihosides G (1), with a new aglycone, and H (2) were isolated from the 95% ethanol extract of Cynanchum taihangense. Their structures were elucidated on the basis of 1 D and 2 D NMR spectral data, HR-ESI-MS analysis and qualitative chemical methods. The compounds were subjected to detect the cytotoxicity against three human tumor cell lines (HL-60, THP-1 and PC-3). The compounds displayed no significant cytotoxicity.Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1672682.

Two new pregnane alkaloids from Pachysandra terminalis Sieb. et Zucc.

Two new pregnane alkaloids, (20S)-20α-cinnamoylamino-3ß-dimethylamino-5-en-pregnane (1) and (20S)-20α-cinnamoylamino-3ß-dimethylamino-pregnane (2), and four known alkaloids (+)-(20S)-20-(dimethylamino)-3-(3'R-isopropyl)-lactam-5α-pregn-2-en-4-one (3), axillaridine A (4), pachysamine M (5) and 20α-dimethylamino-16ß-hydroxy-3ß-senecioylamino-pregn-5-ene (6) were obtained from the whole herb of Pachysandra terminalis Sieb. et Zucc. Their structures were determined by various spectral techniques and computed electronic circular dichroism (ECD) data. Compounds 1-4 were tested for cytotoxicity against three human tumor cell lines and a human umbilical vein endothelial cell (HUVEC) line. Compound 4 exhibited moderate cytotoxicity against MCF-7, U251 and A549 cells with IC50 values of 15.01 ± 0.47 µM, 20.13 ± 1.34 µM and 20.04 ± 1.16 µM, respectively; compounds 1-3 showed weak cytotoxic activity against three tumor cells.

Russelioside B; A pregnane glycoside for treatment of gastric ulcer via modulation of heat shock protein-70 and vascular endothelial growth factor.

Gastric ulcers are a very common public health problem affecting up to 10% worldwide. Russelioside B is a steroidal glycoside isolated from several Caralluma species. No study tested the ulcer healing potential of the compound. The current study aimed to assess the protective effect of russelioside B against ethanol-induced gastric mucosal injury in rats. Ulcer was induced on rats by a single intragastric dose of absolute ethanol (5 mL/kg). Rats were randomly assorted into four groups (n = 8) and given treatments (Antodine, 20 mg/kg or russelioside B, 50 mg/kg) by oral gavage 1 h before ulcer induction. Pretreatment with russelioside B (50 mg/kg) attenuated the gastric mucosal injury as proved by a decrease of ulcer index, and histological scores. It suppressed the gastric inflammation by a significant lowering the tumor necrosis factor-α and interleukin-6 levels with myeloperoxidase activity (which are also aggravating factors in the case of Covid-19 infection). In addition, administration of russelioside B halted the gastric oxidative stress via inhibition of lipid peroxides by maintaining reduced glutathione and by decreasing malondialdehyde. It was able also to restore the sharp drop in the levels of heat shock protein-70, vascular endothelial growth factor and prostaglandin E2 induced by ethanol. Additionally, it showed carbonic anhydrase inhibition activity. The gastroprotective action of russelioside B was umpired through multi mechanistic actions; suppression of gastric oxidative stress, inflammation, anti-apoptotic activities and enhanced gastric mucosal protection by up-regulation of endothelial growth factor, normalization of heat shock protein-70 and prostaglandin E2. These actions were comparable in part to some classical antiulcer drugs such as Antodine.

Cytotoxic Pregnane Steroidal Glycosides from Chonemorpha megacalyx.

Three new C21 pregnane steroids, chonemorphols A-C (1, 3, and 4), 11 new C21 steroidal glycosides, chonemorphosides A-K (2 and 5-14), and 11 known compounds (15-25) were obtained from the vines and leaves of Chonemorpha megacalyx Pierre. Their structures were established using extensive spectroscopic data. The X-ray crystallographic data of 1 and 3 permitted definition of their absolute configurations. Notably, 1 and 2 possessed an uncommon 6/5/6/5/5-fused steroidal ring system. Compound 7 displayed significant cytotoxicity against several cancer cell lines with IC50 values of 2.0-3.6 µM.