Pyrrole-2-carboxaldehydes: Origins and Physiological Activities.

Pyrrole-2-carboxaldehyde (Py-2-C) derivatives have been isolated from many natural sources, including fungi, plants (roots, leaves, and seeds), and microorganisms. The well-known diabetes molecular marker, pyrraline, which is produced after sequential reactions in vivo, has a Py-2-C skeleton. Py-2-Cs can be chemically produced by the strong acid-catalyzed condensation of glucose and amino acid derivatives in vitro. These observations indicate the importance of the Py-2-C skeleton in vivo and suggest that molecules containing this skeleton have various biological functions. In this review, we have summarized Py-2-C derivatives based on their origins. We also discuss the structural characteristics, natural sources, and physiological activities of isolated compounds containing the Py-2-C group.

Identification of Major Antioxidant Compounds from the Edible Mushroom Basidiomycetes-X (Echigoshirayukidake).

Basidiomycetes-X, of which Japanese vernacular name is Echigoshirayukidake, is a local speciality mushroom found and cultivated in Japan that has been distributed as a precious cuisine material or as a functional food with medicinal properties. Antioxidant activity-guided isolation of major ingredients in Basidiomycetes-X revealed the presence of ergosterol, trans-10,cis-12-octadecadienoic acid (a conjugated linolenic acid, 10(E),12(Z)-CLA) and 2,3-dihydro-3,5-dihydroxy-6-methyl­4H­pyran-4-one (DDMP). Approximately 21% of the 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazino radical (DPPH) scavenging activities in the methanolic extract were related to 10(E),12(Z)-CLA, while approximately 6.2% of the activity was related to ergosterol. DDMP was present in both methanolic and water extracts, and the activity related to DDMP was conspicuously detected in water extracts. Moreover, uridine and adenosine were identified as major components of Basidiomycetes-X. The ingredients identified in Basidiomycetes-X are expected to be involved in biological functions observed in this mushroom, which is an attractive functional food resource.

Lauric acid impairs insulin-induced Akt phosphorylation by upregulating SELENOP expression via HNF4α induction.

Selenoprotein P (SeP; encoded by SELENOP in humans, Selenop in rodents) is a hepatokine that is upregulated in the liver of humans with type 2 diabetes. Excess SeP contributes to the onset of insulin resistance and various type 2 diabetes-related complications. We have previously reported that the long-chain saturated fatty acid, palmitic acid, upregulates Selenop expression, whereas the polyunsaturated fatty acids (PUFAs) downregulate it in hepatocytes. However, the effect of medium-chain fatty acids (MCFAs) on Selenop is unknown. Here we report novel mechanisms that underlie the lauric acid-mediated Selenop gene regulation in hepatocytes. Lauric acid upregulated Selenop expression in Hepa1-6 hepatocytes and mice liver. A luciferase promoter assay and computational analysis of transcription factor-binding sites identified the hepatic nuclear factor 4α (HNF4α) binding site in the SELENOP promoter. A chromatin immunoprecipitation (ChIP) assay showed that lauric acid increased the binding of HNF4α to the SELENOP promoter. The knockdown of Hnf4α using siRNA canceled the upregulation of lauric acid-induced Selenop. Thus, the lauric acid-induced impairment of Akt phosphorylation brought about by insulin was rescued by the knockdown of either Hnf4α or Selenop. These results provide new insights into the regulation of SeP by fatty acids and suggest that SeP may mediate MCFA-induced hepatic insulin signal reduction.

Bioactive Phenolic Compounds from Lingonberry (Vaccinium vitis-idaea L.): Extraction, Chemical Characterization, Fractionation and Cellular Antioxidant Activity.

Lingonberries contain high contents of bioactive compounds such as chlorogenic acids and anthocyanins. In addition to radical scavenging and antioxidant activities, these compounds can protect cells from DNA damage. For this reason, lingonberries might be well suited for nutraceuticals or natural biomedicines. To assess these applications, the present study characterized and identified the most effective extract, only consisting of anthocyanins, copigments or a mixture of both, obtained from a lingonberry juice concentrate. An extract was generated by using a XAD-7 column followed by fractionation into anthocyanins and copigments using adsorptive membrane chromatography. After identification of main polyphenols by HPLC-photodiode array-electrospray ionization-tandem mass spectrometry, free radical scavenging activity was analyzed by electron spin resonance spectroscopy using 2,2-diphenyl-1-picrylhydrazyl and galvinoxyl radicals. Furthermore, cyclic voltammetry analyses and the Trolox equivalent antioxidant capacity (TEAC) assay were applied. Finally, the reactive oxygen species (ROS) reducing effects of the lingonberry extract and its fractions were evaluated in HepG2 cells. While the combination of anthocyanins and copigments possessed the highest antioxidant activities, all samples (XAD-7 extract, anthocyanin and copigment fraction) protected cells from oxidative stress. Thus, synergistic effects between phenolic compounds may be responsible for the high antioxidant potential of lingonberries, enabling their use as nutraceuticals.

Pomegranate (Punica granatum L.) Extract and Its Anthocyanin and Copigment Fractions-Free Radical Scavenging Activity and Influence on Cellular Oxidative Stress.

Secondary plant metabolites, e.g., polyphenols, are widely known as health-improving compounds that occur in natural functional foods such as pomegranates. While extracts generated from these fruits inhibit oxidative stress, the allocation of these effects to the different subgroups of substances, e.g., anthocyanins, "copigments" (polyphenols without anthocyanins), or polymeric compounds, is still unknown. Therefore, in the present study, polyphenols from pomegranate juice were extracted and separated into an anthocyanin and copigment fraction using adsorptive membrane chromatography. Phenolic compounds were determined by high performance liquid chromatography with photodiode array (HPLC-PDA) detection and HPLC-PDA electrospray ionization tandem mass spectrometry (HPLC-PDA-ESI-MS/MS), while the free radical scavenging activity of the pomegranate XAD­7 extract and its fractions was evaluated by the Trolox equivalent antioxidant capacity (TEAC) assay and electron spin resonance (ESR) spectroscopy. Compared to juice, the total phenolic content and free radical scavenging potential was significantly higher in the pomegranate XAD-7 extract and its fractions. In comparison to the anthocyanin and copigment fraction, pomegranate XAD-7 extract showed the highest radical scavenging activity against galvinoxyl and DPPH radicals. Moreover, the enriched XAD-7 extract and its fractions were able to protect human hepatocellular HepG2 cells against oxidative stress induced by hydrogen peroxide. Overall, these results indicated that anthocyanins and copigments act together in reducing oxidative stress.

Identification of a Novel Pyrrole Alkaloid from the Edible Mushroom Basidiomycetes-X (Echigoshirayukidake).

Three pyrrole alkaloid derivatives were isolated from the edible mushroom Basidiomycetes-X (Echigoshirayukidake) by water extraction followed by ethyl acetate fractionation. The chemical structures determined by MS and NMR were 4-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl] butanoic acid (compound I), 4-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl] butanamide (compound II), and 5-(hydroxymethyl)-1H-pyrrole-2-carboxaldehyde (compound III). Compound I was found to be the major component, followed by compound II, and compound III was the minor component. The dry powder of Basidiomycetes-X contained approximately 825 µg g-1 compound I and 484 µg g-1 compound II. Compound II was found to be a novel pyrrole aldehyde homologue not previously reported and thus is a specific component of this mushroom.

Plasma half-life and tissue distribution of leukocyte cell-derived chemotaxin 2 in mice.

Leukocyte cell-derived chemotaxin 2 (LECT2) is a hepatokine that causes skeletal muscle insulin resistance. The circulating levels of LECT2 are a possible biomarker that can predict weight cycling because they reflect liver fat and precede the onset of weight loss or gain. Herein, to clarify the dynamics of this rapid change in serum LECT2 levels, we investigated the in vivo kinetics of LECT2, including its plasma half-life and tissue distribution, by injecting 125I-labelled LECT2 into ICR mice and radioactivity tracing. The injected LECT2 was eliminated from the bloodstream within 10 min (approximate half-life, 5 min). In the kidneys, the radioactivity accumulated within 10 min after injection and declined thereafter. Conversely, the radioactivity in urine increased after 30 min of injection, indicating that LECT2 is mainly excreted by the kidneys into the urine. Finally, LECT2 accumulated in the skeletal muscle and liver until 30 min and 2 min after injection, respectively. LECT2 accumulation was not observed in the adipose tissue. These findings are in agreement with LECT2 action on the skeletal muscle. The present study indicates that LECT2 is a rapid-turnover protein, which renders the circulating level of LECT2 a useful rapid-response biomarker to predict body weight alterations.

Inhibition of nuclear factor-κB p65 phosphorylation by 3,4-dihydroxybenzalacetone and caffeic acid phenethyl ester.

3,4-Dihydroxybenzalacetone (DBL) and caffeic acid phenethyl ester (CAPE) are both catechol-containing phenylpropanoid derivatives with various bioactivities. In the present study, we compared the effects of these compounds and other phenylpropanoid derivatives on the activation of nuclear factor-κB (NF-κB) signaling, a major pathway in the inflammatory response, using RAW 264.7 cells. Lipopolysaccharide (LPS)- and interferon γ-induced production of nitrite was strongly suppressed by CAPE and, to a lesser extent, by DBL and caffeic acid ethyl ester. Consistent with these results, induction of NF-κB downstream genes, such as Nitric oxide synthase, interleukin 1 beta, and interleukin 6, and translocation of NF-κB p65 to the nucleus were reduced after LPS stimulation, to a greater extent with CAPE than with DBL. Interestingly, the phosphorylation of p65 was reduced by both compounds, especially by CAPE, even when the level of IκB was not altered. Furthermore, the thiol groups of p65 were modified by CAPE, and the inhibitory effects of CAPE and DBL on the p65 phosphorylation and nitrite production were reversed by pretreatment with thiol-containing reagents. These results suggest that CAPE has strong inhibitory effects on the NF-κB activation that are associated with the modification of thiol groups and phosphorylation of p65.

Characterization of mycosporine-like amino acids in the cyanobacterium Nostoc verrucosum.

The aquatic cyanobacterium Nostoc verrucosum forms macroscopic colonies in streams, and its appearance is superficially similar to that of the terrestrial cyanobacterium Nostoc commune. N. verrucosum is sensitive to desiccation, unlike N. commune, although these Nostoc cyanobacterial species share physiological features, including massive extracellular polysaccharide production and trehalose accumulation capability. In this study, water-soluble sunscreen pigments of mycosporine-like amino acids (MAAs) were characterized in N. verrucosum, and the mysABCD genes responsible for MAA biosynthesis in N. verrucosum and N. commune were compared. N. verrucosum produced porphyra-334 and shinorine, with porphyra-334 accounting for >90% of the total MAAs. Interestingly, porphyra-334 is an atypical cyanobacteial MAA, whereas shinorine is known as a common and dominant MAA in cyanobacteria. Porphyra-334 from N. verrucosum showed little or no radical scavenging activity in vitro, although the glycosylated derivatives of porphyra-334 from N. commune are potent radical scavengers. The presence of the mysABCD gene cluster in N. commune strain KU002 (genotype A) supported its porphyra-334 producing capability via the Nostoc-type mechanism, although the genotype A of N. commune mainly produces the arabinose-bound porphyra-334. The mysABC gene cluster was conserved in N. verrucosum, but the mysD gene was not included in the cluster. These results suggest that the mysABCD gene products are involved in the biosynthesis of porphyra-334 commonly in these Nostoc species, and that the genotype A of N. commune additionally acquired the glycosylation of porphyra-334.

Involvement of Prokineticin 2-expressing Neutrophil Infiltration in 5-Fluorouracil-induced Aggravation of Breast Cancer Metastasis to Lung.

Adjuvant chemotherapy is used for human breast cancer patients, even after curative surgery of primary tumor, to prevent tumor recurrence primarily as a form of metastasis. However, anticancer drugs can accelerate metastasis in several mouse metastasis models. Hence, we examined the effects of postsurgical administration with 5-fluorouracil (5-FU), doxorubicin, and cyclophosphamide, on lung metastasis process, which developed after the resection of the primary tumor arising from the orthotopic injection of a mouse triple-negative breast cancer cell line, 4T1. Only 5-FU markedly increased the numbers and sizes of lung metastasis foci, with enhanced tumor cell proliferation and angiogenesis as evidenced by increases in Ki67-positive cell numbers and CD31-positive areas, respectively. 5-FU-mediated augmented lung metastasis was associated with increases in intrapulmonary neutrophil numbers and expression of neutrophilic chemokines, Cxcl1 and Cxcl2 in tumor cells, with few effects on intrapulmonary T-cell or macrophage numbers. 5-FU enhanced Cxcl1 and Cxcl2 expression in 4T1 cells in a NFκB-dependent manner. Moreover, the administration of a neutrophil-depleting antibody or a Cxcr2 antagonist, SB225002, significantly attenuated 5-FU-mediated enhanced lung metastasis with depressed neutrophil infiltration. Furthermore, infiltrating neutrophils and 4T1 cells abundantly expressed prokineticin-2 (Prok2) and its receptor, Prokr1, respectively. Finally, the administration of 5-FU after the resection of the primary tumor failed to augment lung metastasis in the mice receiving Prokr1-deleted 4T1 cells. Collectively, 5-FU can enhance lung metastasis by inducing tumor cells to produce Cxcl1 and Cxcl2, which induced the migration of neutrophils expressing Prok2 with a capacity to enhance 4T1 cell proliferation. Mol Cancer Ther; 17(7); 1515-25. ©2018 AACR.

3,4-dihydroxybenzalacetone and caffeic acid phenethyl ester induce preconditioning ER stress and autophagy in SH-SY5Y cells.

3,4-dihydroxybenzalacetone (DBL) and Caffeic acid phenethyl ester (CAPE) are both catechol-containing phenylpropanoid derivatives with diverse bioactivities. In the present study, we analyzed the ability of these compounds to activate the unfolded protein response (UPR) and the oxidative stress response. When human SH-SY5Y neuroblastoma cells were treated with DBL or CAPE, the expression of endoplasmic reticulum (ER) stress-related genes such as HSPA5, HYOU1, DDIT3, and SEC61b increased to a larger extent in response to CAPE treatment, while that of antioxidant genes such as HMOX1, GCLM, and NQO1 increased to a larger extent in response to DBL treatment. DNA microarray analysis confirmed the strong link of these compounds to ER stress. Regarding the mechanism, activation of the UPR by these compounds was associated with enhanced levels of oxidized proteins in the ER, and N-acetyl cysteine (NAC), which provides anti-oxidative effects, suppressed the induction of the UPR-target genes. Furthermore, both compounds enhanced the expression of LC3-II, a marker of autophagy, and 4-Phenylbutyric acid (4-PBA), a chemical chaperone that reduces ER stress, suppressed it. Finally, pretreatment of cells with DBL, CAPE or low doses of ER stressors protected cells against a neurotoxin 6-hydroxydopamine (6-OHDA) in an autophagy-dependent manner. These results suggest that DBL and CAPE induce oxidized protein-mediated ER stress and autophagy that may have a preconditioning effect in SH-SY5Y cells.

Anti-Inflammatory Properties of Brazilian Green Propolis Encapsulated in a γ-Cyclodextrin Complex in Mice Fed a Western-Type Diet.

Ageing is often accompanied by chronic inflammation. A fat- and sugar-rich Western-type diet (WTD) may accelerate the ageing phenotype. Cell culture studies have indicated that artepillin C-containing Brazilian green propolis exhibits anti-inflammatory properties. However, little is known regarding its anti-inflammatory potential in mouse liver in vivo. In this study, female C57BL/6NRj wild-type mice were fed a WTD, a WTD supplemented with Brazilian green propolis supercritical extract (GPSE) encapsulated in γ-cyclodextrin (γCD) or a WTD plus γCD for 10 weeks. GPSE-γCD did not affect the food intake, body weight or body composition of the mice. However, mRNA levels of the tumour necrosis factor α were significantly downregulated (p < 0.05) in these mice compared to those in the WTD-fed controls. Furthermore, the gene expression levels of other pro-inflammatory markers, including serum amyloid P, were significantly (p < 0.001) decreased following GPSE-γCD treatment. GPSE-γCD significantly induced hepatic ferritin gene expression (p < 0.01), which may contribute to its anti-inflammatory properties. Conversely, GPSE-γCD did not affect the biomarkers of endogenous antioxidant defence, including catalase, glutathione peroxidase-4, paraoxonase-1, glutamate cysteine ligase and nuclear factor erythroid 2-related factor-2 (Nrf2). Overall, the present data suggest that dietary GPSE-γCD exhibits anti-inflammatory, but not antioxidant activity in mouse liver in vivo. Thus, GPSE-γCD has the potential to serve as a natural hepatoprotective bioactive compound for dietary-mediated strategies against chronic inflammation.

Novel glycosylated mycosporine-like amino acid, 13-O-(ß-galactosyl)-porphyra-334, from the edible cyanobacterium Nostoc sphaericum-protective activity on human keratinocytes from UV light.

A UV-absorbing compound was purified and identified as a novel glycosylated mycosporine-like amino acid (MAA), 13-O-ß-galactosyl-porphyra-334 (ß-Gal-P334) from the edible cyanobacterium Nostoc sphaericum, known as "ge xian mi" in China and "cushuro" in Peru. Occurrence of the hexosylated derivative of shinorine (hexosyl-shinorine) was also supported by LC-MS/MS analysis. ß-Gal-P334 accounted for about 86.5% of total MAA in N. sphaericum, followed by hexosyl-shinorine (13.2%) and porphyra-334 (0.2%). ß-Gal-P334 had an absorption maximum at 334nm and molecular absorption coefficient was 46,700 at 334nm. Protection activity of ß-Gal-P334 from UVB and UVA+8-methoxypsoralen induced cell damage on human keratinocytes (HaCaT) was assayed in comparison with other MAA (porphyra-334, shinorine, palythine and mycosporine-glycine). The UVB protection activity was highest in mycosporine-glycine, followed by palythine, ß-Gal-P334, porphyra-334 and shinorine in order. ß-Gal-P334 had highest protection activity from UVA+8-methoxypsoralen induced cell damage followed by porphyra-334, shinorine, mycosporine-glycine and palythine. We also found an antioxidant (radical-scavenging) activity of ß-Gal-P334 by colorimetric and ESR methods. From these findings, ß-Gal-P334 was suggested to play important roles in stress tolerant mechanisms such as UV and oxidative stress in N. sphaericum as a major MAA. We also consider that the newly identified MAA, ß-Gal-P334 has a potential for use as an ingredient of cosmetics and toiletries.

Eicosapentaenoic acid down-regulates expression of the selenoprotein P gene by inhibiting SREBP-1c protein independently of the AMP-activated protein kinase pathway in H4IIEC3 hepatocytes.

Selenoprotein P (encoded by SELENOP in humans, Selenop in rat), a liver-derived secretory protein, induces resistance to insulin and vascular endothelial growth factor (VEGF) in type 2 diabetes. Suppression of selenoprotein P may provide a novel therapeutic approach to treating type 2 diabetes; however, few drugs inhibiting SELENOP expression in hepatocytes have been identified. The present findings demonstrate that eicosapentaenoic acid (EPA) suppresses SELENOP expression by inactivating sterol regulatory element-binding protein-1c (SREBP-1c, encoded by Srebf1 in rat) in H4IIEC3 hepatocytes. Treatment with EPA caused concentration- and time-dependent reduction in SELENOP promoter activity. EPA activated AMP-activated protein kinase (AMPK); however, the inhibitory effect of EPA on SELENOP promoter activity was not canceled with an AMPK inhibitor compound C and dominant-negative AMPK transfection. Deletion mutant promoter assays and computational analysis of transcription factor-binding sites conserved among the species resulted in identification of a sterol regulatory element (SRE)-like site in the SELENOP promoter. A chromatin immunoprecipitation (ChIP) assay revealed that EPA decreases binding of SREBP-1c to the SELENOP promoter. Knockdown of Srebf1 resulted in a significant down-regulation of Selenop expression. Conversely, SREBP-1c overexpression inhibited the suppressive effect of EPA. These data provide a novel mechanism of action for EPA involving improvement of systemic insulin sensitivity through the regulation of selenoprotein P production independently of the AMPK pathway and suggest an additional approach to developing anti-diabetic drugs.

Deficiency of the hepatokine selenoprotein P increases responsiveness to exercise in mice through upregulation of reactive oxygen species and AMP-activated protein kinase in muscle.

Exercise has numerous health-promoting effects in humans; however, individual responsiveness to exercise with regard to endurance or metabolic health differs markedly. This 'exercise resistance' is considered to be congenital, with no evident acquired causative factors. Here we show that the anti-oxidative hepatokine selenoprotein P (SeP) causes exercise resistance through its muscle receptor low-density lipoprotein receptor-related protein 1 (LRP1). SeP-deficient mice showed a 'super-endurance' phenotype after exercise training, as well as enhanced reactive oxygen species (ROS) production, AMP-activated protein kinase (AMPK) phosphorylation and peroxisome proliferative activated receptor γ coactivator (Ppargc)-1α (also known as PGC-1α; encoded by Ppargc1a) expression in skeletal muscle. Supplementation with the anti-oxidant N-acetylcysteine (NAC) reduced ROS production and the endurance capacity in SeP-deficient mice. SeP treatment impaired hydrogen-peroxide-induced adaptations through LRP1 in cultured myotubes and suppressed exercise-induced AMPK phosphorylation and Ppargc1a gene expression in mouse skeletal muscle-effects which were blunted in mice with a muscle-specific LRP1 deficiency. Furthermore, we found that increased amounts of circulating SeP predicted the ineffectiveness of training on endurance capacity in humans. Our study suggests that inhibitors of the SeP-LRP1 axis may function as exercise-enhancing drugs to treat diseases associated with a sedentary lifestyle.

Time Course Effect of R-Alpha-Lipoic Acid on Cellular Metabolomics in Cultured Hepatoma Cells.

Alpha-lipoic acid (LA) is a powerful antioxidant. LA has two enantiomers, R(+)-LA (R-LA) and S(-)-LA (S-LA). Of these, R-LA is naturally occurring and an essential cofactor in energy metabolism. R-LA treatment has been reported to affect glucose metabolism in rat hepatoma cells. This study analyzed the time course of metabolite levels in LA-treated cultured H4IIEC3 rat hepatoma cells, including a specific evaluation of the effect of R-LA and the enantioselectivity of LA. Principal component analysis showed that this experiment was well designed to observe enantioselectivity. R-LA treatment was found to inhibit the glycolysis and Thr-Gly-Ser pathways, as well as lactic acid production, leading to the inhibition of gluconeogenesis in starved H4IIEC3 cells. This study may provide mechanistic insight into how R-LA induces apoptosis in hepatoma cells.

Rapid response of the steatosis-sensing hepatokine LECT2 during diet-induced weight cycling in mice.

Dieting often leads to body weight cycling involving repeated weight loss and regain. However, little information is available regarding rapid-response serum markers of overnutrition that predict body weight alterations during weight cycling. Here, we report the rapid response of serum leukocyte cell-derived chemotaxin 2 (LECT2), a hepatokine that induces insulin resistance in skeletal muscle, during diet-induced weight cycling in mice. A switch from a high-fat diet (HFD) to a regular diet (RD) in obese mice gradually decreased body weight but rapidly decreased serum LECT2 levels within 10 days. In contrast, a switch from a RD to a HFD rapidly elevated serum LECT2 levels. Serum LECT2 levels showed a positive correlation with liver triglyceride contents but not with adipose tissue weight. This study demonstrates the rapid response of LECT2 preceding body weight alterations during weight cycling in mice and suggests that measurement of serum LECT2 may be clinically useful in the management of obesity.

Free Radical Scavenging and Cellular Antioxidant Properties of Astaxanthin.

Astaxanthin is a coloring agent which is used as a feed additive in aquaculture nutrition. Recently, potential health benefits of astaxanthin have been discussed which may be partly related to its free radical scavenging and antioxidant properties. Our electron spin resonance (ESR) and spin trapping data suggest that synthetic astaxanthin is a potent free radical scavenger in terms of diphenylpicryl-hydrazyl (DPPH) and galvinoxyl free radicals. Furthermore, astaxanthin dose-dependently quenched singlet oxygen as determined by photon counting. In addition to free radical scavenging and singlet oxygen quenching properties, astaxanthin induced the antioxidant enzyme paroxoanase-1, enhanced glutathione concentrations and prevented lipid peroxidation in cultured hepatocytes. Present results suggest that, beyond its coloring properties, synthetic astaxanthin exhibits free radical scavenging, singlet oxygen quenching, and antioxidant activities which could probably positively affect animal and human health.

Chemical Characterization, Free Radical Scavenging, and Cellular Antioxidant and Anti-Inflammatory Properties of a Stilbenoid-Rich Root Extract of Vitis vinifera.

Dietary stilbenoids are receiving increasing attention due to their potential health benefits. However, most studies concerning the bioactivity of stilbenoids were conducted with pure compounds, for example, resveratrol. The aim of this study was to characterize a complex root extract of Vitis vinifera in terms of its free radical scavenging and cellular antioxidant and anti-inflammatory properties. HPLC-ESI-MS/MS analyses of the root extract of Vitis vinifera identified seven stilbenoids including two monomeric (resveratrol and piceatannol), two dimeric (trans-ɛ-viniferin and ampelopsin A), one trimeric (miyabenol C), and two tetrameric (r-2-viniferin = vitisin A and r-viniferin = vitisin B) compounds which may mediate its biological activity. Electron spin resonance and spin trapping experiments indicate that the root extract scavenged 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, galvinoxyl, and superoxide free radicals. On a cellular level it was observed that the root extract of Vitis vinifera protects against hydrogen peroxide-induced DNA damage and induces Nrf2 and its target genes heme oxygenase-1 and γ-glutamylcysteine synthetase. Furthermore, the root extract could induce the antiatherogenic hepatic enzyme paraoxonase 1 and downregulate proinflammatory gene expression (interleukin 1ß, inducible nitric oxide synthase) in macrophages. Collectively our data suggest that the root extract of Vitis vinifera exhibits free radical scavenging as well as cellular antioxidant and anti-inflammatory properties.

Structural Analysis of Crystalline R(+)-α-Lipoic Acid-α-cyclodextrin Complex Based on Microscopic and Spectroscopic Studies.

R(+)-α-lipoic acid (RALA) is a naturally-occurring substance, and its protein-bound form plays significant role in the energy metabolism in the mitochondria. RALA is vulnerable to a variety of physical stimuli, including heat and UV light, which prompted us to study the stability of its complexes with cyclodextrins (CDs). In this study, we have prepared and purified a crystalline RALA-αCD complex and evaluated its properties in the solid state. The results of ¹H NMR and PXRD analyses indicated that the crystalline RALA-αCD complex is a channel type complex with a molar ratio of 2:3 (RALA:α-CD). Attenuated total reflection/Fourier transform infrared analysis of the complex showed the shift of the C=O stretching vibration of RALA due to the formation of the RALA-αCD complex. Raman spectroscopic analysis revealed the significant weakness of the S-S and C-S stretching vibrations of RALA in the RALA-αCD complex implying that the dithiolane ring of RALA is almost enclosed in glucose ring of α-CD. Extent of this effect was dependent on the direction of the excitation laser to the hexagonal morphology of the crystal. Solid-state NMR analysis allowed for the chemical shift of the C=O peak to be precisely determined. These results suggested that RALA was positioned in the α-CD cavity with its 1,2-dithiolane ring orientated perpendicular to the plane of the α-CD ring.