Advanced NMR-Based Structural Investigation of Glucosinolates and Desulfoglucosinolates.

Glucosinolates (GLs) constitute a class of plant secondary metabolites that are characteristic of the order Brassicales. They each contain a common hydrophilic moiety connected to a mostly hydrophobic side chain whose constitution is the most frequent structural variant. Their transformations by myrosinases lead to intensively studied and highly reactive compounds of biological relevancy. In other respects, the enzymatic desulfation of GLs produces derivatives (DS-GLs) that are useful for GL analysis. A collection of 31 compounds, GLs and DS-GLs, representing 17 different side chains was established in order to report accurate descriptions of the molecules' 1H-, 13C-, and 15N-NMR parameters. The descriptions of the 1H-NMR spectra were achieved using the PERCH software, which accurately analyzed the complex coupling patterns that arose from strongly coupled nuclei. The chemical shift assignments were supported by 2D COSY, HSQC, and HMBC spectra. The impact of desulfation and the influence of the nature of the side chains on the chemical shift values are discussed. The results of the spectroscopic analysis and the 3D chemical-structure models of the studied molecules were grouped in structure-and-data-format (SDF) files. The NMR parameters were also collected in a simple text file, a spreadsheet file, and a relational database.

The combined effect of Sango sprout juice and caloric restriction on metabolic disorders and gut microbiota composition in an obesity model.

The main purpose of this study was to compare the benefits of SSJ supplementation in obese rats with those achieved only by switching the alimentary regimen from high-fat (HFD) to the regular one (RD) in liver, ileum and prostate. Furthermore, changings in caecal chime microbiota were investigated. SSJ was administered to rats in combination with a RD (HFD-RD + SSJ). The switch from HFD to RD led to a weight loss of almost 9.8 g, and the total cholesterol was found to be significantly lower. In the HFD-RD + SSJ group, all values were improved compared with the HFD control, and the weight decrement was higher (-23.29 g) with respect to HFD-RD. HFD led to a widespread increment of oxidative stress (OS) markers in liver, ileum and prostate. SSJ has shown to improve the results achieved by the suspension of HFD and it has proven effective wherever the only switch in diet regimen failed.

Glucosinolate Diversity in Bretschneidera sinensis of Chinese Origin.

The glucosinolate (GL) profile in several plant parts (leaf, branch, bark, root, and fruit) of Bretschneidera sinensis from three geographical regions of the People's Republic of China was established for the first time by HPLC. During this investigation, benzyl GL (1), 4-hydroxybenzyl GL (2), 2-hydroxy-2-methylpropyl GL (3), and 4-methoxybenzyl GL (4) were identified. In addition, one new GL, 3-hydroxy-4-methoxybenzyl GL (5), was isolated in a minor amount from the fruit and characterized by spectroscopic data interpretation. Furthermore, traces of 4-hydroxy-3-methoxyphenylacetonitrile were detected by GC-MS analysis in the fruits, thus confirming the presence of the regioisomeric 4-hydroxy-3-methoxybenzyl GL (6). GLs 1-5 were also quantified for the first time by HPLC in the various plant organs.

Glucosinolate distribution in aerial parts of Degenia velebitica.

The glucosinolates present in the leaf, stem, and seed extracts of Degenia velebitica (Degen) Hayek were characterized and quantified according to the ISO 9167-1 method, which is based on the HPLC analysis of desulfoglucosinolates. The stems contained glucoalyssin (3a) as the major compound as well as glucoberteroin (1a) and glucoaubrietin (4a). The leaves contained three glucosinolates, the major one being 3a, followed by glucobrassicanapin (2a) and 1a. Glucoberteroin (1a) was the major glucosinolate in the seeds, along with the two minor glucosinolates 3a and glucoerucin (5a). The content of 1a in the whole, non-defatted seeds amounted to 4% (w/w). The compound was characterized as its desulfo counterpart by spectroscopic techniques.

Glucosinolate profiling and antimicrobial screening of Aurinia leucadea (Brassicaceae).

Glucosinolates (GLs) were characterized in various aerial parts (stems, leaves, and flowers) of Aurinia leucadea (Guss.) C. Koch and quantified according to the ISO 9167-1 official method based on the HPLC analysis of desulfoglucosinolates. Eight GLs, i.e., glucoraphanin (GRA), glucoalyssin (GAL; 1), gluconapin (GNA; 2), glucocochlearin (GCC), glucobrassicanapin (GBN; 3), glucotropaeolin (GTL), glucoerucin (GER), and glucoberteroin (GBE) were identified. The total GL contents were 57.1, 37.8, and 81.3 µmol/g dry weight in the stems, leaves, and flowers, respectively. The major GL detected in all parts of the plant was 2, followed by 1 and 3. GC/MS Analysis of the volatile fractions extracted from the aerial parts of fresh plant material either by hydrodistillation or CH(2) Cl(2) extraction showed that these fractions mostly contained isothiocyanates (ITCs). The main ITCs were but-3-enyl- (55.6-71.8%), pent-4-enyl- (7.6-15.3%), and 5-(methylsulfinyl)pentyl ITC (0-9.5%), originating from the corresponding GLs 2, 3, and 1, respectively. The antimicrobial activity of the volatile samples was investigated by determining inhibition zones with the disk-diffusion method and minimal inhibitory concentrations (MIC) with the microdilution method. They were found to inhibit a wide range of bacteria and fungi, with MIC values of 2.0-32.0 µg/ml, indicating their promising antimicrobial potential, especially against the fungi Candida albicans and Rhizopus stolonifer as well as against the clinically important pathogen Pseudomonas aeruginosa.

Probing for the presence of glucosinolates in three Drypetes spp. (Drypetes euryodes (Hiern) Hutch., Drypetes gossweileri S. Moore, Drypetes laciniata Hutch.) and two Rinorea spp. (Rinorea subintegrifolia O. Ktze and Rinorea woermanniana (Büttner) Engl.) from Gabon.

Drypetes euryodes (Hiern) Hutch., Drypetes gossweileri S. Moore, Drypetes laciniata Hutch. (Putranjivaceae), Rinorea subintegrifolia O. Ktze, and Rinorea woermanniana (Büttner) Engl. (Violaceae) from Gabon were probed for the presence of glucosinolates (GLs). When present, the GLs were identified and quantified by HPLC analysis. 2-Hydroxy-2-methyl GL (1) was the major GL in the cork of D. euryodes. Moreover, 4-hydroxybenzyl GL (2) was the major GL in the seed of D. gossweileri whereas the bark contained 2 as the minor GL and benzyl GL (3) was the major one. In addition, 4-methoxybenzyl GL (4), 3-methoxybenzyl GL (5), and 3 were found in the root of R. subintegrifolia. However, no GL was detected in D. laciniata (leaf and stem), D. euryodes (leaf and stem), and R. woermanniana (leaf and stem-branch). Our results support the hypothesis of the existence of GLs in plants of the Putranjivaceae and Violaceae families (order Malpighiales).

Potent natural soluble epoxide hydrolase inhibitors from Pentadiplandra brazzeana baillon: synthesis, quantification, and measurement of biological activities in vitro and in vivo.

We describe here three urea-based soluble epoxide hydrolase (sEH) inhibitors from the root of the plant Pentadiplandra brazzeana. The concentration of these ureas in the root was quantified by LC-MS/MS, showing that 1, 3-bis (4-methoxybenzyl) urea (MMU) is the most abundant (42.3 µg/g dry root weight). All of the ureas were chemically synthesized, and their inhibitory activity toward recombinant human and recombinant rat sEH was measured. The most potent compound, MMU, showed an IC50 of 92 nM via fluorescent assay and a Ki of 54 nM via radioactivity-based assay on human sEH. MMU effectively reduced inflammatory pain in a rat nociceptive pain assay. These compounds are among the most potent sEH inhibitors derived from natural sources. Moreover, inhibition of sEH by these compounds may mechanistically explain some of the therapeutic effects of P. brazzeana.

Vitexin-2-O-xyloside, raphasatin and (-)-epigallocatechin-3-gallate synergistically affect cell growth and apoptosis of colon cancer cells.

Cytotoxic effects of the combination of the food components vitexin-2-O-xyloside (X), raphasatin (4-methylsulphanyl-3-butenyl isothiocyanates; G) and (-)-epigallocatechin-3-gallate (E) were investigated in colon (LoVo and CaCo-2) and breast (MDA-MB-231 and MCF-7) cancer cells. Breast cancer cells were more resistant than colon cells to X, G and E inhibition. On the contrary, marked synergistic effects among X, G and E on cell growth were found in both colon cancer cells. Further analysis revealed a G0/G1 arrest of the phase cell progression and apoptosis, linked to modulation of Bax, Bcl2, caspase-9 and poly(ADP-ribose) polymerase as well as Reactive Oxygen Species (ROS) generation in both colon cancer cells, whereas apoptosis and ROS were not significantly detected in normal human lymphocytes. We conclude that the X, G and E mixture might act by mitochondrial pathway activation of apoptosis, possibly elicited by ROS and the mixture may be effective in the chemoprevention of colon cancer.

Protective role of (RS )-glucoraphanin bioactivated with myrosinase in an experimental model of multiple sclerosis.

AIM: The discovery of new natural compounds with pharmacological properties is a field of interest widely growing. Recent literature shows that Brassica vegetables (Cruciferae) possess therapeutic effects particularly ascribed due to their content in glucosinolates, which upon myrosinase hydrolysis release the corresponding isothiocyanates. This study examines the potential neuroprotective and immunomodulatory effects of (RS )-glucoraphanin from Tuscan black kale (Brassica oleracea L. var. acephala sabellica) bioactivated with myrosinase (bioactive RS -GRA) (10 mg/kg/day intraperitoneally), in an experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. METHODS: EAE was induced by immunization with myelin oligodendroglial glycoprotein peptide (MOG35-55 ) in mice. After immunization, mice were observed daily for signs of EAE and weight loss. Clinical score was evaluated using a standardized scoring system. RESULTS: By Western blot analysis of spinal cord tissues, we have demonstrated that treatment with bioactive RS -GRA significantly decreased nuclear factor (NF)-kB translocation, pro-inflammatory cytokine production such as interleukin-1ß (IL-1ß), and apoptosis (Bax and caspase 3 expression). CONCLUSION: Our results clearly demonstrate that bioactive RS -GRA treatment may represent a useful therapeutic perspective in the treatment of this disease.

Stability of benzylic-type isothiocyanates in hydrodistillation-mimicking conditions.

Pentadiplandra brazzeana Baillon (Pentadiplandraceae) is known to contain benzyl-, 3-methoxybenzyl-, 4-methoxybenzyl-, 3,4-dimethoxybenzyl-, and indole-type glucosinolates, and the essential oil obtained from its roots is mainly constituted of benzyl isothiocyanate and benzyl cyanide. In a previous study by the authors, it was surmised that partial hydrolytic degradation of 4-methoxybenzyl isothiocyanate, one major expected compound, occurred during the hydrodistillation process of essential oil preparation. To probe this hypothesis, a selection of diversely substituted benzylic-type isothiocyanates was submitted to standard hydrodistillation-mimicking conditions. After extraction with dichloromethane, the reaction mixtures were analyzed using GC-MS. The aqueous phases resulting from liquid-liquid extraction were analyzed by HPLC and GC-MS. 2-Methoxybenzyl, 4-methoxybenzyl, 3,4-dimethoxybenzyl, and 3,4,5-trimethoxybenzyl isothiocyanates underwent conversion into 2-methoxybenzyl, 4-methoxybenzyl, 3,4-dimethoxybenzyl, and 3,4,5-trimethoxybenzyl alcohols, respectively, whereas benzyl, 3-methoxybenzyl, and 4-chlorobenzyl isothiocyanates were converted into the corresponding benzylamines.

Profile and quantification of glucosinolates in Pentadiplandra brazzeana Baillon.

Glucosinolates (GLs) present in root, seed, and leaf extracts of Pentadiplandra brazzeana Baillon were characterized and quantified according to the ISO 9167-1 method based on the HPLC analysis of desulfo-GLs. The analyses were complemented by GC-MS analyses of the isothiocyanates (ITCs) generated from GL degradation by myrosinase. Glucotropaeolin (1a), glucolimnanthin (2a), and glucoaubrietin (3a) were shown to be present in the root extract, whereas the seed mainly contained 3a. 3,4-Dimethoxybenzyl GL (4a), glucobrassicin (5a) and traces of 1a were detected in the leaf extract. The products were fully characterized as their desulfo-counterparts by spectroscopic techniques.

Characterization of the temporal induction of hepatic xenobiotic-metabolizing enzymes by glucosinolates and isothiocyanates: requirement for at least a 6 h exposure to elicit complete induction profile.

A mechanism of action of chemopreventive glucosinolates/isothiocyanates, established largely in vitro, is to modulate carcinogen-metabolizing enzymes. Extrapolation in vivo involves relating in vitro concentrations to plasma/tissue concentrations attained in vivo, thus assuming that even transient exposure modulates enzyme activity. To test this hypothesis, precision-cut rat liver slices were incubated with glucosinolates for up to 24 h, and the O-dealkylation of methoxyresorufin and ethoxyresorufin was determined; increased activities were observed only at incubations of at least 6 h. To evaluate phase II enzymes, isothiocyanates, namely, sulforaphane, erucin, and phenethyl isothiocyanate, were similarly incubated; quinone reductase increased after incubation for 6 h or longer. When glutathione S-transferase was monitored, the phenethyl isothiocyanate-manifested rise necessitated at least a 6 h incubation, whereas in the case of sulforaphane and erucin, the activity was elevated after only 2 h. It is inferred that a rise in carcinogen-metabolizing enzymes by glucosinolates/isothiocyanates necessitates tissue exposure of at least 6 h.

Intact glucosinolates modulate hepatic cytochrome P450 and phase II conjugation activities and may contribute directly to the chemopreventive activity of cruciferous vegetables.

The currently accepted view is that the chemopreventive activity of glucosinolates is exclusively mediated by their degradation products, such as isothiocyanates. In the present study, evidence is presented for the first time that intact glucosinolates can modulate carcinogen-metabolising enzyme systems. The glucosinolates glucoraphanin and glucoerucin were isolated from cruciferous vegetables and incubated with precision-cut rat liver slices. Both glucosinolates elevated the O-dealkylations of methoxy- and ethoxyresorufin, markers for CYP1 activity; supplementation of the incubation medium with myrosinase, the enzyme that converts glucosinolates to their corresponding isothiocyanates, abolished these effects. Moreover, both glucoerucin and glucoraphanin increased the apoprotein levels of microsomal CYP1A1, CYP1A2 and CYP1B1. At higher concentrations, both glucosinolates enhanced quinone reductase activity, whereas glucoraphanin also elevated glutathione S-transferase; in this instance, however, supplementation of the incubation medium with myrosinase exacerbated the inductive effect. Finally, both glucosinolates increased modestly cytosolic quinone reductase, GSTα and GSTµ protein levels, which became more pronounced when myrosinase was added to the incubations with the glucosinolate. It may be inferred that intact glucosinolates can modulate the activity of hepatic carcinogen-metabolising enzyme systems and this is likely to impact on the chemopreventive activity linked to cruciferous vegetable consumption.