Concise synthesis of E/F ring spiroethers from tigogenin. Carbaanalogs of steroidal sapogenins and their biological activity.

A four-step synthesis of five- and six-membered E/F ring spiroethers from tigogenin has been developed. An efficient strategy that features bis-Grignard reaction of dinorcholanic lactone with appropriate bis(bromomagnesio)alkanes followed by acid-mediated spirocyclization was employed to construct a new class of steroid compounds having E and F ring junction as an oxa-carbacyclic system. The synthesized carbaanalogs interact with liposomes and albumin, and also exhibit antibacterial and antifungal activity, demonstrating their pharmacological potential.

Dioscin Ameliorates Hyperuricemia-Induced Atherosclerosis by Modulating of Cholesterol Metabolism through FXR-Signaling Pathway.

Hyperuricemia is one of the independent risk factors for atherosclerotic cardiovascular disease. Herein, we investigate the association between uric acid and cholesterol metabolism and the effect of dioscin on the prevention of hyperuricemia-induced atherosclerosis. In the potassium oxonate-treated ApoE-/--/- mice, atherosclerosis was accelerated along with elevated serum cholesterol levels in the hyperuricemic state, which can be ameliorated by dioscin. Together with the in vitro assays, we found that the effect of dioscin was at least partially through the regulation of the farnesoid X receptor (FXR) -small heterodimer partner (SHP) -7α-hydroxylase (CYP7A1) signaling pathway in the liver. Tigogenin (a metabolite of dioscin) suppressed FXR activation and increased CYP7A1, resulting in an increased conversion rate of cholesterols into bile acids. Further clinical study revealed that treatment with a dioscin-enriched preparation decreased serum cholesterol levels in individuals with hyperuricemia. In summary, this study demonstrated a slowdown effect of dioscin on the progression of hyperuricemia-induced atherosclerosis.

Structural characterization of three cytotoxic steroidal saponins from the leaves of Agave desmetiana hort.

Three steroidal saponins detected by LC-MS were isolated from the leaves of Agave desmetiana hort. The three saponins were characterized as; Tigogenin 3 - [{O - ß - D - xylopyranosyl (1 â†’ 2) - α - L-rhamnopyranosyl (1 â†’ 3)}-ß-D- glucopyranoside), Tigogenin- 3 - ([O- α -L-rhamnopyranosyl (1 â†’ 3) - ß - D - glalactopyranosyl (1 â†’ 2)] - ß - D - glucopyranoside) and Tigogenin- 3 - ([{O - α - L - rhamnopyranosyl (1 â†’ 4)} - ß - D - galactopyranosyl (1 â†’ 3) - ß - D - xylopyranosyl (1 â†’ 2)] - ß - D - glucopyranoside). Identification and structure elucidation of the isolates were done via 1D and 2D NMR techniques, and chemical methods. Cytotoxic activity for the crude saponins and the three isolated compounds were evaluated against Hepg-2 and Mcf-7 cell lines. Compound 2 proved to be the most cytotoxic against tested cell lines with an IC50 2.97 and 2.49 µg/ml respectively.

Synthesis and anti-tumour, immunomodulating activity of diosgenin and tigogenin conjugates.

A series of novel diosgenin (DSG) and tigogenin (TGG) derivatives with diosgenin or tigogenin steroid aglycons linked to levulinic and 3,4-dihydroxycinnamic acids, dipeptides and various amino acids by an ester bond at the C3-oxygen atom of the steroid skeleton has been synthesized. Diosgenyl esters have been prepared by an esterification reaction (DCC/DMAP) of diosgenin with the corresponding acids. All analogues have been evaluated in vitro for their antiproliferative profile against cancer cell lines (MCF-7, MDA-MB-231, PC-3) and human umbilical vein endothelial cells (HUVEC). Analogue2c (l-serine derivative of TGG), the best representative of the series showed IC50 of 1.5 µM (MCF-7), and induced apoptosis in MCF-7 by activating caspase-3/7. The immunomodulatory properties of six synthesized analogues have been determined by examining their effects on the expression of cytokine genes essential for the functioning of the human immune system (IL-1, IL-4, IL-10, IL-12 and TNF-α). Biological evaluation has revealed that new compounds 4c and 16a do not induce the expression of pro-inflammatory cytokines in THP-1 cells after the lipopolysaccharide (LPS) stimulation. They also stimulate the expression of anti-inflammatory IL-10 that acts stronger than diosgenin itself. An in silico ADME properties(absorption, distribution, metabolism, excretion) study was also performed to predict the pharmacokinetic profile of the synthesized compounds. To shed light on the molecular interactions between the synthesized compounds and the glucocorticoid receptor and the estrogen receptor, 2c, 4c and 16a compounds were docked into the active binding sites of these receptors. The in silico and in vitro data suggested that this new group of compounds might be considered as a promising scaffold for further modification of more potent and selective anticancer and immunomodulatory agents.

Simultaneous quantification of polyphenols, glycoalkaloids and saponins in African nightshade leaves using ultra-high performance liquid chromatography tandem mass spectrometry with acid assisted hydrolysis and multivariate analysis.

This study developed comprehensive quantification methods for major nutritive and antinutritive phytochemical aglycones in edible African nightshade leaves, an underutilized food resource in the sub-Saharan area. A simultaneous hydrolysis and extraction method was developed using methanol with 2 M sulfuric acid with incubation at 65 °C for 60 min. UHPLC-QqQ-MS/MS methods were developed and validated for hydrolysis optimization and for quantification of eight major aglycones of polyphenols, alkaloids and sapogenins in 20 differently sourced nightshade leaves, comprising two African species Solanum scabrum and S. nigrum, and from two distinct cultivation sites, one in New Jersey, US and the other in Kenya Eldoret. Variation in species, accessions and cultivation environment played an important role in affecting the phytochemical profile. Total antinutritive alkaloids and sapogenins in all nightshade leaves were evaluated and found to be safe for consumption. This work provides evidence that the consumption of African nightshade leaves as a nutrient rich leafy green vegetable is safe and can contribute to food security and nutritional improvement in the sub-Saharan area.

Beyond tribulus (Tribulus terrestris L.): The effects of phytotherapics on testosterone, sperm and prostate parameters.

ETHNO-PHARMACOLOGICAL RELEVANCE: Phytotherapeutic approaches have been widely proposed to improve male health. Despite the well-touted effects of tribulus (Tribulus terrestris L) on men's health, an optimal phytotherapy remains an elusive challenge. AIM OF THE REVIEW: We sought to critically analyze the evidence in the phytotherapic literature beyond the effects of tribulus on testosterone (T) concentration and sperm analysis to also include indications for prostate health. MATERIALS AND METHODS: A focused literature search was conducted to include studies published in Cochrane, Pubmed, and Web of Science databases between the years 2002 and 2018. RESULTS: The use of tribulus and maca (Lepidium meyenii Walp, Brassicaceae) were not scientifically supported to improve serum T levels in men. Moderate evidence supports the use of long Jack (Eurycoma longifolia Jack, Simaroubaceae), mucuna (Mucuna pruriens (L.) DC., Fabaceae), ashwagandha (Withania somnifera (L.) Dunal, Solanaceae), fenugreek (Trigonella foenum-graceum L., Fabaceae), and black seeds (Nigella sativa L., Ranunculaceae) to increase total T and improve seminal parameters. Data suggests an increase in total T with the use of 5000 mg/d of powdered mucuna seed and ashwagandha root (151 and 143 ng/dL, respectively) over a 12-week period in patients with oligozoospermia. The use of mucuna was supported for patients with oligozoospermia to improve sperm parameters, with an increase of 83.3 million/mL observed after use of 5000 mg/d of powdered mucuna seed over a 12-week period. Evidence supporting the use of saw palmetto (Serenoa repens, (W.Bartram) Small, Arecaceae) to improve prostate health remains equivocal; whereas, evidence supporting the use of Pygeum africanum Hook.f., Rosaceae, Urtica dioica L., Urticaceae, beta-sitosterols, pollen extract, onion, garlic, and tomato, appears favorable and promising. CONCLUSION: Scientific evidence supports the use of mucuna and ashwagandha as phytotherapics for improving serum T concentrations and semen parameters. Despite inconclusive evidence for use of tribulus as a T booster, it may provide advantageous effects on sperm parameters in men with idiopathic infertility. Nutraceutical strategies and some phytotherapics may also be effective to promote prostate health. Popular foodstuffs (onion, garlic, and tomato), nutraceutical agents (pollen extract and beta-sitosterols), and herbal medicines (Pygeum africanum and Urtica dioica) are rational approaches.

Effect and mechanism of dioscin from Dioscorea spongiosa on uric acid excretion in animal model of hyperuricemia.

ETHNOPHARMACOLOGY RELEVANCE: Dioscin, a spirostane glycoside, the rhizoma of Dioscorea septemloba (Diocoreacea) is used for diuresis, rheumatism, and joints pain. Given the poor solubility and stability of Dioscin, we proposed a hypothesis that Dioscin's metabolite(s) are the active substance(s) in vivo to contribute to the reducing effects on serum uric acid levels. AIM OF THE STUDY: The aim of this study is to identify the active metabolite(s) of Dioscin in vivo and to explore the mechanism of its antihyperuricemic activity. MATERIALS AND METHODS: After oral administration of Dioscin in potassium oxonate (PO) induced hyperuricemia rats and adenine-PO induced hyperuricemia mice models, serum uric acid and creatinine levels, clearance of uric acid and creatinine, fractional excretion of uric acid, and renal pathological lesions were determined were used to evaluate the antihyperuricemic effects. Renal glucose transporter-9 (GLUT-9) and organic anion transporter-1 (OAT-1) expressions were analyzed by western blotting method. Renal uric acid excretion was evaluated using stably urate transporter-1 (URAT-1) transfected human epithelial kidney cell line. Intestinal uric acid excretion was evaluated by measuring the transcellular transport of uric acid in HCT116 cells. RESULTS: In hyperuricemia rats, both 25 and 50mg/kg of oral Dioscin decreased serum uric acid levels over 4h. In the hyperuricemia mice, two weeks treatment of Dioscin significantly decreased serum uric acid and creatinine levels, increased clearance of uric acid and creatinine, increased fractional excretion of uric acid, and reduced renal pathological lesions caused by hyperuricemia. In addition, renal GLUT -9 was significantly down-regulated and OAT-1 was up-regulated in Dioscin treated hyperuricemia mice. Dioscin's metabolite Tigogenin significantly inhibited uric acid re-absorption via URAT1 from 10 to 100µM. Diosgenin and Tigogenin increased uric acid excretion via ATP binding cassette subfamily G member 2 (ABCG2). CONCLUSION: Decreasing effect of Dioscin on serum uric acid level and enhancing effect on urate excretion were confirmed in hyperuricemia animal models. Tigogenin, a metabolite of Dioscin, was identified as an active substance with antihyperuricemic activity in vivo, through inhibition of URAT1 and promotion of ABCG2.

Synthesis of tigogenin MeON-Neoglycosides and their antitumor activity.

To discover new potent cytotoxic steroidal saponins, a series of tigogenin neoglycosides were synthesized via oxyamine neoglycosylation for the first time. The preliminary bioassays for their in vitro antitumor activities against five human cancer cell lines (A375, A-549, HCT-116, HepG2 and MCF-7) were conducted. The results revealed a sugar-dependent activity profile of their cytotoxicity, the glycoconjugation converted the non-active tigogenin to the most potential product Tg29 ((3R)-N-methoxyamino-tigogenin-ß-2-deoxy-d-galactoside) with IC50 value of 2.7µM and 4.6µM against HepG2 and MCF-7 cells respectively. And the 3R-tigogenin neoglycosides exhibited enhanced antitumor activity while the 3S-tigogenin almost showed no activity. Among the five cell lines, HepG2 and MCF-7 cells showed more sensitive cytotoxic responses to the products. Therefore, the neoglycosylation could be a promising strategy for the synthesis of antitumor steroidal saponins and it also proved the essential role of carbohydrate moiety of steroidal saponins in the biological activity.

Regio- and stereoselective cleavage of steroidal 22-oxo-23-spiroketals catalyzed by BF3·Et2O.

The regioselective opening of the F ring of 22-oxo-23-spiroketals using BF3·OEt2 in acetic anhydride yielded novel cholestanic frameworks with pyranone E ring 20-23. The structures of the new derivatives of botogenin, diosgenin, hecogenin and tigogenin thus obtained were established using one and two dimensional (1)H, (13)C experiments (DEPT, COSY, HETCOR, HMBC). The X-ray diffraction analysis unequivocally confirmed the R configuration at C-23 in the starting 22-oxo-23-spiroketal 18 and the Z configuration of the C23-C24 double bond in the reaction product 20.

UPLC-QTOF-MS identification of metabolites in rat biosamples after oral administration of Dioscorea saponins: a comparative study.

ETHNOPHARMACOLOGICAL RELEVANCE: Among the 49 species of the genus Dioscorea distributed in China, Dioscorea nipponica Makino (DN), Dioscorea panthaica Prain et Burkill (DP), and Dioscorea zingiberensis C. H. Wright (DZ) possess more or less similar traditional therapeutic actions, such as activating blood, relieving pain, and dispersing swelling; they have been used as folk medicine in China since 1950s. The modern pharmaceutical industry has developed these three species as herbal medicines that have been used for decades for treating cardiovascular diseases. However, there is no available information in the literature explaining how their chemical components are converted and interrelated in vivo to support their efficacies. The present study aimed to a) compare the metabolic profiles of saponins from DN, DP and DZ, which are considered to be their bioactive components, and b) to compare the changes in sustained levels of metabolites from rat biosamples. MATERIAL AND METHODS: Total saponins (TS) from each of the three species, and four individual saponins, namely protodioscin (PD), pseudoprotodioscin (PSD), dioscin (DC) and diosgenin (DG), were given to rats by oral administration. Chemical profiles of the rats' plasma, urine and feces were monitored 1-36 h. A UPLC-QTOF-MS based method was performed to identify the absorbed constituents and their metabolic products in rat biosamples (i.e., blood, urine, and feces); the ratio of peak area of major saponins to that of internal standard was calculated and plotted versus time to characterize the sustained levels of saponins in biosamples. RESULTS: Totally 10 saponin-related compounds were detected in rat plasma, 10 in rat urine and 18 in rat feces. The results indicated that formation of diosgenin by desugarization was the main pathway by which steroidal glycosides were metabolized. Other types of bio-transformation were found among glycosides and aglycones, such as ring cyclization through loss of 26-O-glucosyl, substitution of ß-D-glucopyranosyl for α-L-rhamnopyrannosyl, hydrogenation of diosgenin at 5(6)-double bond, and hydration of 20(22)-double bond. Generally, the metabolic profiles of DN and DP were shown to be quite similar, but different from that of DZ. However, some particular similarities and connections were found among these three TS. Diosgenin was one of the main metabolites commonly found in plasma and feces (excluding urine), from all groups receiving different TS, as well as individual saponins; this is likely to be one of the bioactive constituents playing an essential role in cardioprotective efficacy. Furostane-type saponins in TS of DN, DP or DZ, such as PD, protogracillin, parvifloside, protodeltonin and protobioside, showed fast absorption into blood (<1h), but were maintained for a relatively short period (mostly<8h), while the spirostane-type saponin and sapogenin (DC and DG, respectively), were absorbed into circulation more slowly (>1h), but increased gradually and lasted longer (>36h). These two patterns suggest that the therapeutic effect of these Dioscorea saponins is achieved through a complex, multi-step process over time. In addition, it appears that PD, PSD, and DC contained in DN and DP were transformed into certain glycosides originally found in DZ but not in DN or DP (protodeltonin, deltonin, trillin, and progenin II), which might indicate another linkage among these three species. CONCLUSION: These similarities and connections described above constitute evidence supporting similarity in efficacy of these three herbs from the perspective of metabolism. The UPLC-QTOF-MS based method is accurate and efficient for analyzing metabolic changes in rat biosamples over time.

Biotransformation of steroidal saponins in sisal (Agave sisalana Perrine) to tigogenin by a newly isolated strain from a karst area of Guilin, China.

A rod-shaped bacterium was isolated from the soil in a karst area of Guilin, China and its biotransformation of steroidal saponins in sisal (Agave sisalana Perrine) to tigogenin was presented for the first time. A total of 22 strains for the degradation of steroidal saponins in sisal were isolated from 48 soil samples, and the isolated rod-shaped, bacterial strain ZG-21 was used for the production of tigogenin due to its highest degradation efficiency of steroidal saponins in sisal. The parameters affecting biotransformation by strain ZG-21 were optimized. Under the optimized conditions of temperature (30 °C), pH (6), time (5 days) and substrate concentration (5 mg/mL), a maximum tigogenin yield of 26.7 mg/g was achieved. Compared with the conventional method of acid hydrolysis, the biotransformation method provided a clean and eco-friendly alternative for the production of tigogenin.

Applications of the hexanic fraction of Agave sisalana Perrine ex Engelm (Asparagaceae): control of inflammation and pain screening

The present study evaluated the anti-inflammatory and analgesic properties of Agave sisalana Perrine in classic models of inflammation and pain. The hexanic fraction of A. sisalana (HFAS) was obtained by acid hydrolysis followed by hexanic reflux. Anti-inflammatory properties were examined in three acute mouse models (xylene ear oedema, hind paw oedema and pleurisy) and a chronic mouse model (granuloma cotton pellet). The antinociceptive potential was evaluated in chemical (acetic-acid) and thermal (tail-flick and hot-plate test) models of pain. When given orally, HFAS (5, 10, 25 and 50 mg/kg) reduced ear oedema (p < 0.0001; 52%, 71%, 62% and 42%, respectively). HFAS also reduced hind paw oedema at doses of 10 mg/kg and 25 mg/kg (p < 0.05; 42% and 58%, respectively) and pleurisy at doses of 10 mg/kg and 25 mg/kg (41% and 50%, respectively). In a chronic model, HFAS reduced inflammation by 46% and 58% at doses of 10 mg/kg and 25 mg/kg, respectively. Moreover, this fraction showed analgesic properties against the abdominal writhing in an acetic acid model (at doses of 5-25 mg/kg) with inhibitory rates of 24%, 54% and 48%. The HFAS also showed an increased latency time in the hot-plate (23% and 28%) and tail-flick tests (61% and 66%) for the 25 mg/kg and 50 mg/kg doses, respectively. These results suggest that HFAS has anti-inflammatory and analgesic properties.

Comparison of main saponins from fruits and whole plant of Tribulus terrestris L. by RP-HPLC / 中成药

AIM: To compare the main saponins extracted respectively from the fruits and the whole plant of Tribulus terrestris L. and study its marked component. METHODS: Using C 18 ODS column and Refractive Index Detector, we compared the main saponins extracted respectively from the fruits and the whole plant of Tribulus terrestris L. in quantity by RP-HPLC. RESULTS: Tigogeniin contents from herb and its fruit had distinct difference between them (P