Structural Moieties Required for Cinnamaldehyde-Related Compounds to Inhibit Canonical IL-1ß Secretion.

Suppressing canonical NOD-like receptor protein 3 (NLRP3) inflammasome-mediated interleukin (IL)-1ß secretion is a reliable strategy for the development of nutraceutical to prevent chronic inflammatory diseases. This study aimed to find out the functional group responsible for the inhibitory effects of cinnamaldehyde-related compounds on the canonical IL-1ß secretion. To address this, the suppressing capacities of six cinnamaldehyde-related compounds were evaluated and compared by using the lipopolysaccharide (LPS)-primed and adenosine 5'-triphosphate (ATP)-activated macrophages. At concentrations of 25~100 µM, cinnamaldehyde and 2-methoxy cinnamaldehyde dose-dependently inhibited IL-1ß secretion. In contrast, cinnamic acid, cinnamyl acetate, cinnamyl alcohol and α-methyl cinnamaldehyde did not exert any inhibition. Furthermore, cinnamaldehyde and 2-methoxy cinnamaldehyde diminished expressions of NLRP3 and pro-IL-1ß. Meanwhile, cinnamaldehyde and 2-methoxy cinnamaldehyde prevented the ATP-induced reduction of cytosolic pro-caspase-1 and increase of secreted caspase-1. In conclusion, for cinnamaldehyde-related compounds to suppress NLRP3 inflammasome-mediated IL-1ß secretion, the propenal group of the side chain was essential, while the substituted group of the aromatic ring played a modifying role. Cinnamaldehyde and 2-methoxy cinnamaldehyde exerted dual abilities to inhibit canonical IL-1ß secretion at both stages of priming and activation. Therefore, there might be potential to serve as complementary supplements for the prevention of chronic inflammatory diseases.

Comparison of Inhibitory Capacities of 6-, 8- and 10-Gingerols/Shogaols on the Canonical NLRP3 Inflammasome-Mediated IL-1ß Secretion.

Endogenous noninfectious substances that mediate the nucleotide oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation and interleukin (IL)-1ß secretion causes inappropriate sterile inflammation and is implicated in the pathogenesis of several chronic diseases, such as type 2 diabetes mellitus, gout, atherosclerosis and Alzheimer's disease. Consequently, dietary phytochemicals exhibiting capacities to suppress canonical NLRP3 inflammasome-mediated IL-1ß secretion can be a reliable supplement to prevent such diseases. The purpose of this study was to investigate and compare the inhibitory effects of ginger phytochemicals, including 6-, 8- and 10-gingerols/shogaols on the canonical NLRP3 inflammasome-mediated IL-1ß secretion in THP-1 macrophages with ordered stimulations of lipopolysaccharide (LPS) and adenosine 5'-triphosphate (ATP). At 20 µM, the 10-gingerol and all the shogaols significantly inhibited canonical IL-1ß secretion. The shogaols had a more potent inhibitory capacity than that of corresponding gingerols. Increase of alkyl chain length impacted negatively the inhibitory activity of shogaols. Additionally, these effective ginger phytochemicals not only inhibited the LPS-primed expression of pro-IL-1ß and NLRP3, but also decreased ATP-activated caspase-1. The results demonstrated that ginger phytochemicals, especially the most potent, 6-shogaol, might be promising for developing as an inhibitor of the canonical NLRP3 inflammasome-mediated IL-1ß secretion and further applied in prevention of NLRP3 inflammasome-associated diseases.

Characterization of particulate-phase polycyclic aromatic hydrocarbons emitted from incense burning and their bioreactivity in RAW264.7 macrophage.

This study investigated the effects of particle-bound polycyclic aromatic hydrocarbons (PAHs) produced from burning three incense types on and their bioreactivity in the RAW 264.7 murine macrophage cell line. Gas chromatography/mass spectrometry was used to determine the levels of 16 identified PAHs. Macrophages were exposed to incense particle extracts at concentrations of 0, 3.125, 6.25, 12.5, 25, 50, and 100 µg/mL for 24 h. After exposure, cell viability and nitric oxide (NO) and inflammatory mediator [tumor necrosis factor (TNF)-α] production of the cells were examined. The mean atomic hydrogen (H) to carbon (C) ratios in the environmentally friendly, binchotan charcoal, and lao shan incenses were 0.69, 1.13, and 1.71, respectively. PAH and total toxic equivalent (TEQ) mass fraction in the incenses ranged from 137.84 to 231.00 and 6.73-26.30 pg/µg, respectively. The exposure of RAW 264.7 macrophages to incense particles significantly increased TNF-α and NO production and reduced cell viability. The cells treated with particles collected from smoldering the environmentally friendly incense produced more NO and TNF-α compared to other incenses. Additionally, the TEQ of fluoranthene (FL), pyrene (Pyr), benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (INP), dibenz[a,h]anthracene (DBA), and benzo[g,h,i]perylene [B(ghi)P] had a significant correlation (R2 = 0.64-0.98, P < 0.05) with NO and TNF-α production. The current findings indicate that incense particle-bound PAHs are biologically active and that burning an incense with a lower H/C ratio caused higher bioreactivity. The stimulatory effect of PAH-containing particles on molecular mechanisms of inflammation are critical for future study.

Evaluating the anti-neuroinflammatory capacity of raw and steamed garlic as well as five organosulfur compounds.

The anti-neuroinflammatory capacities of raw and steamed garlic extracts as well as five organosulfur compounds (OSCs) were examined in lipopolysaccharide (LPS)-stimulated BV2 microglia. According to those results, steaming pretreatment blocked the formation of alliinase-catalyzed OSCs such as allicin and diallyl trisulfide (DATS) in crushed garlic. Raw garlic, but not steamed garlic, dose-dependently attenuated the production of LPS-induced nitric oxide (NO), interleukin-1ß (IL-1ß), tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein-1 (MCP-1). DATS and diallyl disulfide at 200 and 400 µM, respectively, displayed significant anti-neuroinflammatory activity. Meanwhile, even at 1 mM, diallyl sulfide, S-allyl cysteine and alliin did not display such activity. Inhibition of nuclear factor-κB activation was the mechanism underlying this protective effect of raw garlic and DATS. Analysis results indicated that the anti-neuroinflammatory capacity of raw garlic is due to the alliin-derived OSCs. Importantly, DATS is a highly promising therapeutic candidate for treating inflammation-related neurodegenerative diseases.

Hesperidin, nobiletin, and tangeretin are collectively responsible for the anti-neuroinflammatory capacity of tangerine peel (Citri reticulatae pericarpium).

Inhibiting microglial activation-mediated neuroinflammation has become a convincing target for the development of functional foods to treat neurodegenerative diseases. Tangerine peel (Citri reticulatae pericarpium) has potent anti-inflammatory capacity; however, its anti-neuroinflammatory capacity and the corresponding active compounds remain unclear. To this end, the composition of a tangerine peel ethanolic extract was analysed by LC-MS, and the anti-neuroinflammatory ability was evaluated using a lipopolysaccharide (LPS)-activated BV2 microglia culture system. Hesperidin is the most predominant flavonoid in tangerine peel, followed by tangeretin and nobiletin. Among the eight tested flavanone glycosides and polymethoxy flavones, only nobiletin displayed a capacity of>50% to inhibit LPS-induced proinflammatory NO, TNF-α, IL-1ß and IL-6 secretion at a concentration of 100 µM. At 2 mg/ml, tangerine peel extract attenuated LPS-induced NO, TNF-α, IL-1ß and IL-6 secretion by 90.6%, 80.2%, 66.7%, and 86.8%, respectively. Hesperidin, nobiletin, and tangeretin individually (at concentrations of 135, 40, and 60 µM, respectively) in 2 mg/ml tangerine peel extract were only mildly inhibitory, whereas in combination, they significantly inhibited LPS-induced proinflammatory cytokine expression at levels equal to that of 2 mg/ml tangerine peel extract. Overall, tangerine peel possesses potent anti-neuroinflammatory capacity, which is attributed to the collective effect of hesperidin, nobiletin, and tangeretin.

Anti-neuroinflammatory capacity of fresh ginger is attributed mainly to 10-gingerol.

Despite the anti-neuroinflammatory capacity of ginger, the corresponding active constituents are unclear. This study analyzed the composition of fresh ginger ethanolic extract by using LC-MS. Inhibitory activities of fresh ginger extract and seven gingerol-related compounds on the neuro-inflammation were also evaluated by using a lipopolysaccharide (LPS)-activated BV2 microglia culture model. Except for zingerone and 6-gingerol, other gingerols and shogaols at a concentration of 20 µM inhibited the production of nitric oxide, IL-1ß, IL-6 and TNF-α as well as their mRNA levels in LPS-activated BV2 microglia. Blocking NF-κB activation was the underlying mechanism responsible for inhibiting the proinflammatory gene expression. Increasing the alkyl chain length enhanced the anti-neuroinflammatory capacity of gingerols yet, conversely, attenuated those of shogaols. 6-Gingerol was the most abundant compound in the fresh ginger extract, followed by 10-gingerol. Furthermore, fresh ginger extract exhibited a significant anti-neuroinflammatory capacity, which was largely owing to 10-gingerol, but not 6-gingerol.

Inhibition of neuroinflammation by cinnamon and its main components.

Uncontrolled activation of microglia contributes to neuroinflammation, which is highly involved in the development of neurodegenerative diseases. Although cinnamon has neuro-protective properties, its capacity to inhibit neuroinflammation has not been investigated and its active compounds remain unclear. Therefore, the composition of cinnamon extract was analysed by LC-MS and the ability of cinnamon and its main constituents to inhibit neuroinflammation was evaluated using a lipopolysaccharide (LPS)-activated BV2 microglia culture system. In total, 50 µg/mL cinnamon extract decreased significantly the production and expression of nitric oxide (NO), interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α in LPS-activated BV2 microglia. Blocking of nuclear factor-κB (NF-κB) activation was the most likely mechanism responsible for inhibition by cinnamon of neuroinflammation. Among the eight tested compounds, cinnamaldehyde had the greatest anti-neuroinflammatory capacity. Experimental results suggest that cinnamon may have a potential therapeutic effect against neurodegenerative diseases and its potent anti-neuroinflammatory capacity was primarily attributed to cinnamaldehyde.

Protective effect of green tea (-)-epigallocatechin-3-gallate against the monoamine oxidase B enzyme activity increase in adult rat brains.

OBJECTIVE: Monoamine oxidase B (MAO-B) levels were observed increasing during aging in rat brains. (-)-Epigallocatechin-3-gallate (EGCG) is the major polyphenolic constituent in green tea. The objective of the present study was to investigate the EGCG compound for its effect on preventing an increase in MAO-B activity in rat brains. The total antioxidant capacity and lipid peroxidation of rats were also assessed. METHODS: Rats were assigned to three groups: Control, VE (α-tocopherol), and EGCG. Twenty-four male Long-Evans rats were fed normal diets for a total of 11 wk and test diets for a total of 12 wk. The serum analysis, serum total antioxidant capacity, tissue lipid peroxidation, and monoamine oxidase B enzyme activity were measured. The differences between the groups and between the control and experimental groups were analyzed. The correlation among the experimental results was also analyzed. RESULTS: The serum total antioxidant capacity of the EGCG group was higher than that observed in the Control and VE groups. In rat brains and livers, the lipid peroxidation levels were lower in the VE and EGCG groups compared with Control groups. EGCG and VE groups showed lower MAO-B enzyme activity in rat brains compared with Control groups. In contrast to the brain findings, there were no significant differences in the MAO-B enzyme activity among groups in rat livers. CONCLUSION: The present study first indicates that EGCG supplementation was able to execute a tissue-selective decrease in the brain MAO-B enzyme activity in adult rats, in which it was actualized by way of preventing physiological peroxidation.

Investigation of heat treating conditions for enhancing the anti-inflammatory activity of citrus fruit (Citrus reticulata) peels.

In traditional Chinese medicine, dried citrus fruit peels are widely used as remedies to alleviate coughs and reduce phlegm in the respiratory tract. Induction of inducible nitric oxide synthase (iNOS) in inflammatory cells and increased airway production of nitric oxide (NO) are well recognized as key events in inflammation-related respiratory tract diseases. Despite the fact that the enhancing effect of heat treatment on the antioxidant activity of citrus fruit peels has been well documented, the impact of heat treatment on citrus peel beneficial activities regarding anti-inflammation is unclear. To address this issue, we determined the anti-inflammatory activities of heat-treated citrus peel extracts by measuring their inhibitory effect upon NO production by lipopolysaccharide-activated RAW 264.7 macrophages. Results showed that the anti-inflammatory activity of citrus peel was significantly elevated after 100 degrees C heat treatment in a time-dependent fashion during a period from 0 to 120 min. Inhibition of iNOS gene expression was the major NO-suppressing mechanism of the citrus peel extract. Additionally, the anti-inflammatory activity of citrus peel extract highly correlated with the content of nobiletin and tangeretin. Conclusively, proper and reasonable heat treatment helped to release nobiletin and tangeretin, which were responsible for the increased anti-inflammatory activity of heat-treated citrus peels.

Heat treatment enhances the NO-suppressing and peroxynitrite-intercepting activities of kumquat (Fortunella margarita Swingle) peel.

In Taiwan, folk remedies containing dried kumquats (Fortunella margarita Swingle) are used to cure inflammatory respiratory disorders. The induction of inducible nitric oxide (NO) synthase in inflammatory cells and increased airway production of NO and peroxynitrite, its derivative, are key events in such disorders. Although heat is known to affect the antioxidant activity of citrus peels, the effects of dehydration and heating on NO suppression and on the interception of peroxynitrite are unclear. We determined the NO-suppressing activities of freeze-dried, oven-dried, and heat-treated kumquat extracts by measuring their inhibition of NO production in lipopolysaccharide-activated RAW 264.7 macrophages. Furthermore, we evaluated the attenuation of peroxynitrite-mediated nitrotyrosine formation in albumin. Heating, but not oven drying, enhanced the ability of kumquat peels to suppress NO and intercept peroxynitrite, as compared with freeze drying. However, heat treatment and oven drying of kumquat flesh attenuated these activities; these effects were at least partially attributed to heat-susceptible ascorbate.

Protective capacities of certain spices against peroxynitrite-mediated biomolecular damage.

Peroxynitrite, a potent cytotoxic agent, can damage a variety of biomolecules such as proteins, lipids, and DNA, and is considered as one of the major pathological causes of several diseases. Therefore, it would appear likely that interception of peroxynitrite by certain dietary compounds may represent one mechanism by which such foods may exert their beneficial action in vivo. A number of researchers have speculated that certain spices, rich in phenolics, may, conceivably, act as potential protectors against the actions of peroxynitrite. Eight culinary spices including cardamom, cinnamon, cloves, cumin, nutmeg, paprika, rosemary and turmeric were selected for study purposes. Further, the protective effects of methanol extracts of such spices against peroxynitrite-mediated damage to proteins, lipids and DNA were evaluated as determined by these extracts' ability to attenuate the formation of, respectively, nitrotyrosine in albumin, thiobarbiturate acid-reactive substances (TBARS) in liposome and strand breakages for plasmid DNA. All of the tested spices exerted some level of protective ability against peroxynitrite-mediated biomolecular damage. Amongst them, cloves deserve special attention due to their outstanding protective abilities against two of three forms of peroxynitrite-mediated biomolecular damage. Additionally, the phenolic content of certain spices appears to correlate well with such spices' protective effect against peroxynitrite-mediated tyrosine nitration and lipid peroxidation. Such an observation indicates that phenolics present in the spices contributed to such spice-elicited protection against peroxynitrite toxicity.

Suppressive effect of a proanthocyanidin-rich extract from longan (Dimocarpus longan Lour.) flowers on nitric oxide production in LPS-stimulated macrophage cells.

Anthocyanidins found in certain flowers have been shown to act as strong antioxidants in various systems, exhibiting multiple biological actions. The antioxidative effects of water extract and ethanolic extract of longan (Dimocarpus longan Lour.) flowers were evaluated by radical scavenging activity and compared to those of gallic acid, myricetin, and epigallocatechin gallate. In this study, the suppressive effects of longan flower extracts on nitric oxide and prostaglandin E2 production were investigated using a lipopolysaccharide-stimulated RAW 264.7 cell model. Abundant levels of phenolic compounds including flavonoids, condensed tannins, and proanthocyanidins were found in water or ethanolic extracts prepared from dried longan flowers. The antioxidative effect of longan flower extract was similar to the effect exhibited by pure antioxidants. Moreover, longan flower extract showed prominent inhibitory effects on prostaglandin E2 production. Significant concentration-dependent inhibition of nitric oxide production was detected when cells were cotreated with lipopolysaccharide and various concentrations of longan flower extracts. These inhibitory effects were further attributed to suppression of inducible nitric oxide synthase protein expression and not to reduced enzymatic activity. These results suggest that longan flower crude extracts, especially ethanolic extract, have antioxidant and anti-inflammatory effects, and the probable mechanism involves inhibition of inflammation by proanthocyanidins. Preliminary observations suggest that longan flower extract, especially alcoholic extract, could be another potential source of natural dietary antioxidant and anti-inflammatory agent.

Evaluation of NO-suppressing activity of several Mediterranean culinary spices.

Excess nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is implicated in the development of a number of diseases. Due to the absence of any natural specific enzymatic defense system in vivo, the consumption of certain foods which exhibit selective suppressive ability as regards NO overproduction might boost the host's protective effects against NO-mediated toxicity. Spices, rich in phenolics, are speculated conceivably to act as potential NO-scavengers or iNOS suppressors. The relative NO-suppressing activity of methanol extracts deriving from nine Mediterranean culinary spices was determined by measuring their inhibitory effect upon NO production for lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. In addition, the specifics of the suppressing mechanism were further explored. All of the spices tested, with the exception of clove, displayed a rather linear dose-dependent NO-suppressing effect without there appearing to exist any effect upon cell viability. Furthermore, the NO-suppressing capacity of certain spices was able to be ranked based upon their IC(50) (the concentration of spice extracts is required to cause 50% inhibition of NO production by LPS-activated RAW 264.7 cells), the ranking appearing as: rosemary (0.031%)>tarragon (0.052%)>cinnamon (0.059%)>oregano (0.106%)>basil (0.162%)>marjoram (0.236%)>allspice (0.269%)>and thyme (0.270%). Only cinnamon displayed excellent NO-scavenging ability, whereas all of the other spices demonstrated moderate to poor activities in this regard. Moreover, the inhibitory effect of tested spices upon the iNOS protein level was almost equivalent to their suppressive effect upon NO production. It would appear that inhibition of iNOS expression was the primary mechanism of action of spices as regards their exerting NO-suppressing activity.

Maternal plasma adiponectin concentrations at 24 to 31 weeks of gestation: negative association with gestational diabetes mellitus.

OBJECTIVE: Adiponectin is an adipocyte-derived hormone with antidiabetic, antiatherosclerotic, and antiinflammatory properties. This study investigated the relations between maternal adiponectin concentration and gestational diabetes mellitus (GDM) and other metabolic parameters during midpregnancy. METHODS: Two-hour 75-g oral glucose tolerance tests were performed in 253 pregnant women at 24 to 31 wk of gestation. Two hundred nineteen who had normal glucose tolerance (NGT) and 34 women who had GDM and their newborns were investigated. Fasting maternal blood samples were drawn to determine plasma concentrations of adiponectin, glucose, insulin, C-peptide, free fatty acid, and blood lipids. Blood samples at 1 and 2 h after an oral glucose load were obtained to measure plasma glucose, insulin, and C-peptide concentrations. RESULTS: Plasma adiponectin concentrations were significantly lower in women who had GDM than in those who had NGT (P = 0.014). Maternal age, body mass index (before pregnancy and at blood collection), and plasma level of free fatty acid were significantly greater in those who had GDM than in those who had NGT. Logistic regression analysis showed that maternal adiponectin level and GDM were significantly correlated (P = 0.043), but that the correlation became weaker (P = 0.116) after adjusting for maternal body mass index and plasma level of free fatty acid before pregnancy. In the NGT group, maternal adiponectin concentrations were significantly negatively correlated with plasma fasting insulin, fasting C-peptide, fasting C-peptide/fasting glucose ratio, 2-h glucose, triacylglycerol, and maternal body mass index and positively correlated with high-density lipoprotein cholesterol concentration. In the GDM group, maternal adiponectin level was negatively correlated with neonatal birth weight. CONCLUSIONS: Midpregnancy hypoadiponectinemia may be associated with a higher risk of GDM.

Lack of relationship between beta3-adrenergic receptor gene polymorphism and gestational diabetes mellitus in a Taiwanese population.

The Trp64Arg polymorphism of beta(3)-adrenergic receptor (ADRB3) has been reported to be associated with insulin resistance and gestational diabetes mellitus (GDM). The objective of this study is to investigate whether the ADRB3 Arg variant confers susceptibility to GDM in a Taiwanese population. A total of 299 pregnant women (mean +/- SD, 31.1 +/- 4.2 years) was recruited. Two-hour, 75-g oral glucose tolerance tests (OGTT) were conducted at 24 to 31 weeks gestation (28.3 +/- 1.6 weeks). Forty-one GDM subjects and 258 controls with normal glucose tolerance (NGT) level were genotyped for the ADRB3 Trp64Arg polymorphism. The genotype distribution and allele frequency of ADRB3 did not significantly differ between GDM and NGT subjects (9.8% v 14.5%). Body weight gain during pregnancy was not different between ADRB3 genotypes. However, the GDM subjects with the Arg64 variant had higher fasting (P =.04) and postload 120 minutes (P =.03) insulin levels as compared with the GDM subjects with the Trp64Trp allele. In all subjects, the women with the Arg64 allele (n = 76) had significantly higher level of insulin secretion (the ratio of Deltainsulin(60)/Deltaglucose(60)) during OGTT than those without (n = 223) (P =.03) despite similar plasma levels of glucose and insulin in both genotypes. Our results indicated that the ADRB3 Trp64Arg variant is not related to the development of GDM and has no effect on obesity during pregnancy in a Taiwanese population. However, ADRB3 polymorphism might be a possible determinant of insulin resistance.

Cord plasma concentrations of adiponectin and leptin in healthy term neonates: positive correlation with birthweight and neonatal adiposity.

OBJECTIVE: Adiponectin is negatively associated with leptin, insulin and obesity in children and adults. Whereas increases in fetal insulin and leptin are associated with increased weight and adiposity at birth, the role of adiponectin in fetal growth has not yet been determined. The aims of this study were to examine the relationships between adiponectin and insulin, leptin, weight and adiposity at birth in healthy term infants. DESIGN AND METHODS: Anthropometric parameters including weight, length, circumferences and skinfold thickness were measured, and plasma lipid profiles, insulin, leptin and adiponectin concentrations in cord blood samples from 226 singleton infants born at term after uncomplicated pregnancies were assayed. RESULTS: Cord plasma adiponectin, leptin and insulin levels correlated significantly and positively with birthweight (P = 0.001, P < 0.001, P < 0.001, respectively) and the sum of skinfold thicknesses (P < 0.001, P < 0.001, P < 0.001, respectively). Mean cord plasma adiponectin and leptin levels, but not insulin level, were significantly higher in large-for-gestational-age (LGA) infants compared with appropriate-for-gestational-age (AGA) infants. Cord plasma leptin concentration, but not adiponectin concentration, was significantly higher in female infants than in male infants (P = 0.003 and P = 0.94, respectively). Cord plasma adiponectin concentration correlated positively with leptin level (P = 0.007) but not with insulin level (P = 0.78). CONCLUSIONS: High adiponectin levels are present in the cord blood. Cord plasma adiponectin and leptin levels are positively correlated with birthweight and adiposity. This suggests that adiponectin may be involved in regulating fetal growth.