Enhanced wound healing potential of arabincoside B isolated from Caralluma Arabica in rat model; a possible dressing in veterinary practice.

BACKGROUND: Wound management is a critical procedure in veterinary practice. A wound is an injury that requires the body's cells' alignment to break down due to external assault, such as trauma, burns, accidents, and diseases. Re-epithelization, extracellular matrix deposition, especially collagen, inflammatory cell infiltration, and development of new blood capillaries are the four features that are used to evaluate the healing process. Using a natural extract for wound management is preferred to avoid the side effects of synthetic drugs. The current study aimed to assess the effect of major pregnane glycoside arabincoside B (AR-B) isolated from Caralluma arabica (C. arabica) for the wound healing process. METHOD: AR-B was loaded on a gel for wound application. Rats were randomly distributed into six groups: normal, positive control (PC), MEBO®, AR-B 0.5%, AR-B 1%, and AR-B 1.5%, to be 6 animals in each group. Wounds were initiated under anesthesia with a 1 cm diameter tissue needle, and treatments were applied daily for 14 days. The collected samples were tested for SOD, NO, and MDA. Gene expression of VEGF and Caspase-3. Histopathological evaluation was performed at two-time intervals (7 and 14 days), and immunohistochemistry was done to evaluate α -SMA, TGF-ß, and TNF-α. RESULT: It was found that AR-B treatment enhanced the wound healing process. AR-B treated groups showed reduced MDA and NO in tissue, and SOD activity was increased. Re-epithelization and extracellular matrix deposition were significantly improved, which was confirmed by the increase in TGF-ß and α -SMA as well as increased collagen deposition. TNF-α was reduced, which indicated the subsiding of inflammation. VEGF and Caspase-3 expression were reduced. CONCLUSION: Our findings confirmed the efficiency of AR-B in enhancing the process of wound healing and its potential use as a topical wound dressing in veterinary practice.

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.

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.

In Silico and In Vitro Screening of Some Pregnane Glycosides Isolated from Certain Caralluma Species as SARS-COV-2 Main Protease Inhibitors.

SARS-CoV-2 caused pandemic represented a major risk for the worldwide human health, animal health and economy, forcing extraordinary efforts to discover drugs for its prevention and cure. Considering the extensive interest in the pregnane glycosides because of their diverse structures and excellent biological activities, we investigated them as antiviral agents against SARS-COV-2. We selected 21 pregnane glycosides previously isolated from the genus Caralluma from Asclepiadaceae family to be tested through virtual screening molecular docking simulations for their potential inhibition of SARS-CoV-2 Mpro. Almost all target compounds showed a more or equally negative docking energy score relative to the co-crystallized inhibitor X77 (S=-12.53 kcal/mol) with docking score range of (-12.55 to -19.76 kcal/mol) and so with a potent predicted binding affinity to the target enzyme. The activity of the most promising candidates was validated by in vitro testing. Arabincoside C showed the highest activity (IC50=35.42 µg/ml) and the highest selectivity index (SI=9.9) followed by Russelioside B (IC50=50.80 µg/ml), and Arabincoside B (IC50=53.31 µg/ml).

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.

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.

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.

Pregnane neurosteroids exert opposite effects on GABA and glycine-induced chloride current in isolated rat neurons.

The ability of endogenous neurosteroids (NSs) with pregnane skeleton modified at positions C-3 and C-5 to modulate the functional activity of inhibitory glycine receptors (GlyR) and ionotropic É£-aminobutyric acid receptors (GABAA R) was estimated. The glycine and GABA-induced chloride current (IGly and IGABA ) were measured in isolated pyramidal neurons of the rat hippocampus and in isolated rat cerebellar Purkinje cells, respectively. Our experiments demonstrated that pregnane NSs affected IGABA and IGly in a different manner. At low concentrations (up to 5 µM), tested pregnane NSs increased or did not change the peak amplitude of the IGABA , but reduced the IGly by decreasing the peak amplitude and/or accelerating desensitization. Namely, allopregnanolone (ALLO), epipregnanolone (EPI), pregnanolone (PA), pregnanolone sulfate (PAS) and 5ß-dihydroprogesterone (5ß-DHP) enhanced the IGABA in Purkinje cells. Dose-response curves plotted in the concentration range from 1 nM to 100 µM were smooth for EPI and 5ß-DHP, but bell-shaped for ALLO, PA and PAS. The peak amplitude of the IGly was reduced by PA, PAS, and 5α- and 5ß-DHP. In contrast, ALLO, ISO and EPI did not modulate it. Dose-response curves for the inhibition of the IGly peak amplitude were smooth for all active compounds. All NSs accelerated desensitization of the IGly . The dose-response relationship for this effect was smooth for ALLO, PA, PAS and 5ß-DHP, but it was U-shaped for EPI, 5α-DHP and ISO. These results, together with our previous results on NSs with androstane skeleton, offer comprehensive overview for understanding the mechanisms of effects of NSs on IGly and IGABA .

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.

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.

Three New Pregnanes Isolated from the Cynanchum auriculatum.

Three new compounds named cynansteroid A (1), cynansteroid B (2) and cynansteroid C (3), together with nine known C21 -steroidal pregnane sapogenins (4-12) were isolated from the hydrolytic extract of the roots of Cynanchum auriculatum. The structures of cynansteroid A-C (1-3) were ascertained via the detailed analysis of the HR-ESI-MS, 1D and 2D NMR, and the calculated and experimental ECD data of cynansteroid B (2). Compound 11 displayed moderate inhibitory activity toward Verticillium dahliae Kleb (IC50 =37.15 µM), furthermore, compounds 11 and 12 showed significant inhibitory activity against Phomopsis sp. (IC50 =16.49 µM and 17.62 µM, respectively).

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.

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.

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.

Minor immunosuppressive spiroorthoester group-containing pregnane glycosides from the root barks of Periploca sepium.

LC-MS guided chemical investigation of the periploside-rich extract of the root barks of Periploca sepium afforded six new minor pregnane glycosides, named periplosides A1-A6 (1-6). Their structures were characterized on the basis of extensive spectroscopic analysis. Compounds 1-6 were evaluated for their inhibitory activities against the proliferation of T and B lymphocytes in vitro, among them, compound 5 exhibited significant inhibitory activities and the most favorite selective index (SI) values against the proliferation of T lymphocyte (IC50 = 0.30 µM, SI = 176) and B lymphocyte (IC50 = 0.55 µM, SI = 97).

Trichilones A-E: New Limonoids from Trichilia adolfi.

In addition to the trichilianones A-D recently reported from Trichilia adolfi, a continuing investigation of the chemical constituents of the ethanol extract of the bark of this medicinal plant yielded the five new limonoids 1-5. They are characterized by having four fused rings and are new examples of prieurianin-type limonoids, having a ε-lactone which in 4 and 5 is α, ß- unsaturated. The structures of the isolated metabolites were determined by high field NMR spectroscopy and HR mass spectrometry. The new metabolites were shown to have the ε-lactone fused with a tetrahydrofuran ring which is connected to an oxidized hexane ring joined with a cyclo-pentanone having a 3-furanyl substituent. As the crude extract possesses antileishmanial activity, the compounds were assayed for cytotoxic and antiparasitic activities in vitro in murine macrophage cells (raw 264.7 cells) and in Leishmania amazoniensis as well as L. braziliensis promastigotes. Metabolites 1-3 and 5 showed moderate cytotoxicity (between 30-94 µg/mL) but are not responsible for the antileishmanial effect of the extract.

Synthesis and Characterization of Bone Binding Antibiotic-1 (BBA-1), a Novel Antimicrobial for Orthopedic Applications.

Osteomyelitis and orthopedic infections are major clinical problems, limited by a lack of antibiotics specialized for such applications. In this paper, we describe the design and synthesis of a novel bone-binding antibiotic (BBA-1) and its subsequent structural and functional characterization. The synthesis of BBA-1 was the result of a two-step chemical conjugation of cationic selective antimicrobial-90 (CSA-90) and the bisphosphonate alendronate (ALN) via a heterobifunctional linker. This was analytically confirmed by HPLC, FT-IR, MS and NMR spectroscopy. BBA-1 showed rapid binding and high affinity to bone mineral in an in vitro hydroxyapatite binding assay. Kirby-Baur assays confirmed that BBA-1 shows a potent antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus comparable to CSA-90. Differentiation of cultured osteoblasts in media supplemented with BBA-1 led to increased alkaline phosphatase expression, which is consistent with the pro-osteogenic activity of CSA-90. Bisphosphonates, such as ALN, are inhibitors of protein prenylation, however, the amine conjugation of ALN to CSA-90 disrupted this activity in an in vitro protein prenylation assay. Overall, these findings support the antimicrobial, bone-binding, and pro-osteogenic activities of BBA-1. The compound and related agents have the potential to ensure lasting activity against osteomyelitis after systemic delivery.

Five New Pregnane Glycosides from Gymnema sylvestre and Their α-Glucosidase and α-Amylase Inhibitory Activities.

Gymnema sylvestre, a medicinal plant, has been used in Indian ayurvedic traditional medicine for the treatment of diabetes. Phytochemical investigation of Gymnema sylvestre led to the isolation of five new pregnane glycosides, gymsylosides A-E (1-5) and four known oleanane saponins, 3ß-O-ß-D-glucopyranosyl (1→6)-ß-D-glucopyranosyl oleanolic acid 28-O-ß-D-glucopyranosyl ester (6), gymnemoside-W1 (7), 3ß-O-ß-D-xylopyranosyl-(1→6)-ß-D- glucopyranosyl-(1→6)-ß-D-glucopyranosyl oleanolic acid 28-O-ß-D-glucopyranosyl ester (8), and alternoside XIX (9). Their structures were identified based on spectroscopic evidence and comparison with those reported in the literature. All compounds were evaluated for their α-glucosidase and α-amylase inhibitory activities. Compounds 2-4 showed significant α-amylase inhibitory activity, with IC50 values ranging from 113.0 to 176.2 µM.

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.

In vitro modulation of multidrug resistance by pregnane steroids and in vivo inhibition of tumour development by 7α-OBz-11α(R)-OTHP-5ß-pregnanedione in K562/R7 and H295R cell xenografts.

Synthetic progesterone and 5α/ß-pregnane-3,20-dione derivatives were evaluated as in vitro and in vivo modulators of multidrug-resistance (MDR) using two P-gp-expressing human cell lines, the non-steroidogenic K562/R7 erythroleukaemia cells and the steroidogenic NCI-H295R adrenocortical carcinoma cells, both resistant to doxorubicin. The maximal effect in both cell lines was observed for 7α-O-benzoyloxy,11α(R)-O-tetrahydropyranyloxy-5ß-pregnane-3,20-dione 4. This modulator co-injected with doxorubicin significantly decreased the tumour size and increased the survival time of immunodeficient mice xenografted with NCI-H295R or K562/R7 cells.