Caffeic acid phenethyl ester ameliorates imidacloprid-induced acute toxicity in the rat cerebral cortex

This study aimed to investigate the role of caffeic acid phenethyl ester (CAPE), a compound found in propolis, on imidacloprid (IMI), a nicotinic acetylcholine receptor agonist that causes cerebral toxicity. 60 adult rats were randomly divided into five groups: control, IMI (100 mg/kg), and IMI+CAPE (1, 5, 10 mg/kg). Cerebral cortex tissue was examined histopathologically, biochemically, spectrophotometrically and immunohistochemically. The results showed that IMI caused toxicity in the cerebral cortex. However, CAPE (5 and 10 mg/kg) attenuated the deteriorated histopathological score and normalized the apoptotic markers (Bax and Caspase-3). Additionally, CAPE dose-dependently normalized the levels of TNF-α, dopamin, GFAP and NGF, and at the highest dose (10 mg/kg) also normalized the balance of oxidative parameters (MDA, SOD, CAT, and GSH). In conclusion, the antioxidant, anti-inflammatory, and anti-apoptotic effects of CAPE may be a promising treatment for acute IMI-induced cerebral cortex toxicity.

Caffeic Acid Phenethyl Ester Inhibits Basal Lipolysis by Activating PPAR-Gamma and Increasing Lipid Droplet-Associated Perilipin in Mature Rat Adipocytes

Abnormal lipolysis is correlated with metabolic syndrome. Caffeic acid phenethyl ester (CAPE), a natural product from honeybee hives, has been reported to improve metabolic syndrome. However, the effects of CAPE on lipolysis and perilipin-1 (the major lipid droplet-associated protein) in mature adipocytes were not clarified. In this study, mature adipocytes were isolated from the epididymal fat pads of male rats and incubated with CAPE to estimate lipolysis by measuring glycerol release. It was found that the basal lipolysis was inhibited by CAPE in a dose- and time-dependent manner. The lipid droplet-associated perilipin-1 and phosphorylated peroxisome proliferator-activated receptor (PPAR) gamma levels increased following CAPE treatment by Western blot analysis. Moreover, a specific PPAR-gamma inhibitor (T0070907) could partly reverse the effect of CAPE on basal lipolysis. Furthermore, treatment of adipocytes with dibutyryl-cAMP (db-cAMP) or isoproterenol (ISO) increased lipolysis, but the drug-induced lipolysis was abrogated by combination treatment with CAPE. The lipid droplet-associated perilipin-1 level was also decreased in the drug-induced groups but increased when combined treatment with CAPE. In conclusion, our results revealed that a decrease in basal lipolysis and an increase in lipid droplet-associated perilipin-1 levels induced by CAPE may be involved in the regulation of lipid metabolism through activation of PPAR-gamma in mature adipocytes.

The Anti-Inflammatory Properties of Chaga Extracts Obtained by Different Extraction Methods against LPS-Induced RAW 264.7

Chaga, a sclerotia formed by the Inonotus obliquus fungus, has been widely recognized for a number of medicinal properties. Although numerous scientific investigations have been published describing various biological activities of chaga from different geographical locations, little work has focused on chaga harvested in the USA or extraction techniques to maximize anti-inflammatory properties. The aim of this study was to investigate the anti-inflammatory properties of chaga collected in Maine (USA) extracted using traditional aqueous (hot water steeping) methods against lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Chaga extracts obtained from both conventional (ethanol/water) extraction methods and an accelerated solvent extraction method (ASE) at optimized conditions were compared to aqueous extracts (tea) obtained from chaga in the powder form (P) and powder form in tea bags (B) based on their effect on both nitric oxide (NO) production and pro-inflammatory cytokine expression, in particular, the expression of TNF-α, interleukin-6 (IL-6), and interleukin-β (IL-1β). Phenolic acid extracts from chaga and individual phenolic acid standards were also investigated for their effect on the same parameters. Results indicated that various chaga extracts have significant anti-inflammatory activity on LPS-stimulated RAW 264.7 cells. The inhibitory effect was through a decrease in the production of NO and the downregulation of TNF-α, IL-6, and IL-1β in RAW 264.7 macrophages. ASE1 (novel, optimized ethanol/water extraction) and P6 (six-minute steeping of powder in 100 °C water) extracts showed the highest inhibitory activity on NO production and on the expression of the inflammatory cytokines, compared to extracts obtained by conventional extraction methods.

The NLRP3 Inflammasome Pathway: A Review of Mechanisms and Inhibitors for the Treatment of Inflammatory Diseases

The NLRP3 inflammasome is a multiprotein complex that plays a pivotal role in regulating the innate immune system and inflammatory signaling. Upon activation by PAMPs and DAMPs, NLRP3 oligomerizes and activates caspase-1 which initiates the processing and release of pro-inflammatory cytokines IL-1β and IL-18. NLRP3 is the most extensively studied inflammasome to date due to its array of activators and aberrant activation in several inflammatory diseases. Studies using small molecules and biologics targeting the NLRP3 inflammasome pathway have shown positive outcomes in treating various disease pathologies by blocking chronic inflammation. In this review, we discuss the recent advances in understanding the NLRP3 mechanism, its role in disease pathology, and provide a broad review of therapeutics discovered to target the NLRP3 pathway and their challenges.

Polyphenols: Potential anti-inflammatory agents for treatment of metabolic disorders

Ample evidence highlights the potential benefits of polyphenols in health status especially in obesity-related metabolic disorders such as insulin resistance, type 2 diabetes, and cardiovascular diseases. Mechanistically, due to the key role of "Metainflammation" in the pathomechanism of metabolic disorders, recently much focus has been placed on the properties of polyphenols in obesity-related morbidities. This narrative review summarizes the current knowledge on the role of polyphenols, including genistein, chlorogenic acid, ellagic acid, caffeic acid, and silymarin in inflammatory responses pertinent to metabolic disorders and discusses the implications of this evidence for future directions. This review provides evidence that the aforementioned polyphenols benefit health status in metabolic disorders via direct and indirect regulation of a variety of target proteins involved in inflammatory signaling pathways. However, due to limitations of the in vitro and in vivo studies and also the lack of long-term human clinical trials studies, further high-quality investigations are required to firmly establish the clinical efficacy of the polyphenols for the prevention and management of metabolic disorders.

Immunomodulatory Effects of Dietary Polyphenols

Functional and nutraceutical foods provide an alternative way to improve immune function to aid in the management of various diseases. Traditionally, many medicinal products have been derived from natural compounds with healing properties. With the development of research into nutraceuticals, it is becoming apparent that many of the beneficial properties of these compounds are at least partly due to the presence of polyphenols. There is evidence that dietary polyphenols can influence dendritic cells, have an immunomodulatory effect on macrophages, increase proliferation of B cells, T cells and suppress Type 1 T helper (Th1), Th2, Th17 and Th9 cells. Polyphenols reduce inflammation by suppressing the pro-inflammatory cytokines in inflammatory bowel disease by inducing Treg cells in the intestine, inhibition of tumor necrosis factor-alpha (TNF-α) and induction of apoptosis, decreasing DNA damage. Polyphenols have a potential role in prevention/treatment of auto-immune diseases like type 1 diabetes, rheumatoid arthritis and multiple sclerosis by regulating signaling pathways, suppressing inflammation and limiting demyelination. In addition, polyphenols cause immunomodulatory effects against allergic reaction and autoimmune disease by inhibition of autoimmune T cell proliferation and downregulation of pro-inflammatory cytokines (interleukin-6 (IL-6), IL-1, interferon-γ (IFN-γ)). Herein, we summarize the immunomodulatory effects of polyphenols and the underlying mechanisms involved in the stimulation of immune responses.

Anti-Obesity Effect of Dictyophora indusiata Mushroom Polysaccharide (DIP) in High Fat Diet-Induced Obesity via Regulating Inflammatory Cascades and Intestinal Microbiome

Obesity is a multifactorial metabolic disorder characterized by low-grade chronic inflammation, hyper-permeability of the gut epithelium, and perturbation of the intestinal microbiome. Despite the numerous therapeutic efficacies of Dictyophora indusiata mushroom, its biological activity in alleviating obesity through regulation of the gut microbiota and inflammatory cascades remain obscure. Henceforth, we determined the modulatory impact of D. indusiata polysaccharide (DIP) in the high-fat diet (HFD)-induced obesity mice model. The experimental subjects (BALB/C mice) were supplemented with chow diet (Control group), high-fat diet (HFD group), or HFD along with DIP at a low dose [HFD + DIP(L)] and high dose [HFD + DIP(H)]. Obesity-related parameters, including body weight gain, epididymal adipocyte size, fat accumulation, adipogenic markers, lipogenic markers, inflammatory associated markers, intestinal integrity, and intestinal microbiome, were elucidated. Our findings demonstrated that the oral administration of DIP at low dose partially and at high dose significantly reversed HFD-induced obesity parameters. Furthermore, the body weight, fat accumulation, adipocyte size, adipogenic and liver associated markers, glucose levels, inflammatory cytokines, and endotoxin (Lipopolysaccharide, LPS) levels were reduced considerably. Moreover, the study revealed that DIP treatment reversed the dynamic alterations of the gut microbiome community by decreasing the Firmicutes to Bacteroidetes ratio. These findings led us to infer the therapeutic potential of DIP in alleviating HFD-induced obesity via regulating inflammatory cascades, modulating intestinal integrity and intestinal microbiome community.

Anti‑inflammatory effects of leaf and branch extracts of honeyberry (Lonicera caerulea) on lipopolysaccharide‑stimulated RAW264.7 cells through ATF3 and Nrf2/HO‑1 activation

Honeyberry (Lonicera caerulea) has long been used as a traditional medicine in China, Japan and northern Russia. Functional studies of honeyberry have mainly focused on the fruits, which have been reported to exert various pharmacological activities, including anti-inflammatory activity, with limited or no studies on the other parts of the plant, such as the leaves and branches. In the present study, the anti-inflammatory effects of extracts of the leaves (HBL), branches (HBB) and fruit (HBF) of honeyberry plant were evaluated in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. HBL and HBB significantly inhibited the production of pro-inflammatory mediators in LPS-stimulated RAW264.7 cells, and the inhibitory effects of HBL and HBB were stronger than those of HBF. HBL and HBB blocked the nuclear accumulation of p65 independently of IκB-α. HBL did not inhibit the phosphorylation of ERK1/2 or p38; however, HBB effectively inhibited the phosphorylation of p38 but not ERK1/2. HBL and HBB increased the expression of heme oxygenase-1 (HO-1) protein by inducing the nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) through the activation of the reactive oxygen species (ROS)/p38 pathway; the reduction in inducible nitric oxide synthase (iNOS) and interleukin-1β (IL-1β) expression by HBL and HBB was inhibited by HO-1 knockdown. In addition, HBL and HBB increased the expression of activating transcription factor-3 (ATF3), and the reduction in iNOS and IL-1β expression by HBL and HBB was inhibited by ATF3 knockdown. Collectively, HBL and HBB inhibited LPS-induced nuclear factor-κB activation by blocking the nuclear accumulation of p65, increasing HO-1 expression through activation of the ROS/p38/Nrf2 pathway, and increasing ATF3 expression. Furthermore, HBB inhibited LPS-induced p38 phosphorylation. These findings suggest that HBL and HBB may have great potential as natural products for the development of anti-inflammatory drugs.

Caffeic acid phenethyl ester counteracts doxorubicin-induced chemobrain in Sprague-Dawley rats: Emphasis on the modulation of oxidative stress and neuroinflammation

Chemotherapy-induced cognitive dysfunction (chemobrain) is one of the major complaints for cancer patients treated with chemotherapy such as Doxorubicin (DOX). The induction of oxidative stress and neuroinflammation were identified as major contributors to such adverse effect. Caffeic acid phenethyl ester (CAPE) is a natural polyphenolic compound, that exhibits unique context-dependent antioxidant activity. It exhibits pro-oxidant effects in cancer cells, while it is a potent antioxidant and cytoprotective in normal cells. The present study was designed to investigate the potential neuroprotective effects of CAPE against DOX-induced cognitive impairment. Chemobrain was induced in Sprague Dawley rats via systemic DOX administration once per week for 4 weeks (2 mg/kg/week, i.p.). CAPE was administered at 10 or 20 μmol/kg/day, i.p., 5 days per week for 4 weeks. Morris water maze (MWM) and passive avoidance tests were used to assess learning and memory functions. Oxidative stress was evaluated via the colorimetric determination of GSH and MDA levels in both hippocampal and prefrontal cortex brain regions. However, inflammatory markers, acetylcholine levels, and neuronal cell apoptosis were assessed in the same brain areas using immunoassays including either ELISA, western blotting or immunohistochemistry. DOX produced significant impairment in learning and memory as indicated by the data generated from MWM and step-through passive avoidance tests. Additionally DOX-triggered oxidative stress as evidenced from the reduction in GSH levels and increased lipid peroxidation. Treatment with DOX resulted in neuroinflammation as indicated by the increase in NF-kB (p65) nuclear translocation in addition to boosting the levels of pro-inflammatory mediators (COX-II/TNF-α) along with the increased levels of glial fibrillary acid protein (GFAP) in the tested tissues. Moreover, DOX reduced acetylcholine levels and augmented neuronal cell apoptosis as supported by the increased active caspase-3 levels. Co-treatment with CAPE significantly counteracted DOX-induced behavioral and molecular abnormalities in rat brain tissues. Our results provide the first preclinical evidence for CAPE promising neuroprotective activity against DOX-induced neurodegeneration and memory deficits.

Brazilian propolis extract reduces intestinal barrier defects and inflammation in a colitic mouse model

Brazilian propolis is rich in cinnamic acid derivatives and reportedly reduces intestinal inflammation in rodents; however, the underlying mechanisms remain unclear. We hypothesized that the regulation of tight junction (TJ) barrier, Th17 cell differentiation, and/or, macrophage activation by cinnamic acid derivatives were involved in the propolis-mediated anti-inflammatory effect. Mice were orally administered 2% dextran sodium sulfate (DSS) in combination with either the feeding control or a diet containing 0.3% ethanol extract of Brazilian propolis for 9 days. DSS administration induced acute colitis in mice, whereas the propolis extract mitigated DSS-induced weight loss; colon shortening; increased plasma levels of lipopolysaccharide-binding protein; reduced expression of TJ proteins, such as zonula occludens, junctional adhesion molecule-A, occludin, and claudins; and increased expression of inflammatory cytokines, such as tumor necrosis factor (TNF) α, interleukin (IL) 6, and IL-17a. Cinnamic acid derivatives, such as artepillin C and caffeic acid phenethyl ester, present in the propolis extract suppressed the IL-17 production from cultured murine splenocytes through decreased retinoic acid-related orphan receptor gT expression. Baccharin, drupanin, and culifolin, which are also present in Brazilian propolis, reduced the TNF-α and/or IL-6 production by suppressing inflammatory signaling in murine RAW 264.7 macrophages. Taken together, the regulation of Th17 differentiation and macrophage activation by cinnamic acid derivatives, at least in part, contribute to the anti-inflammatory effect mediated by Brazilian propolis.

Synthesis, Antibacterial Evaluation, and QSAR of Caffeic Acid Derivatives

The present study evaluates the antibacterial effects of a set of 16 synthesized caffeic acid ester derivatives against strains of Staphylococcus aureus and Escherichia coli, as well as discusses their structure-activity relationship (SAR). The antibacterial assays were performed using microdilution techniques in 96-well microplates to determine minimal inhibitory concentration (MIC). The results revealed that five of the compounds present strong to optimum antibacterial effect. Of the sixteen ester derivatives evaluated, the products with alkyl side chains, as propyl caffeate (3), butyl caffeate (6), and pentyl caffeate (7), presented the best antibacterial activity with MIC values of around 0.20 μM against Escherichia coli and only butyl caffeate (6) showing the same MIC against Staphylococcus aureus. For products with aryl substituents, the best MIC results against the tested strain of Escherichia coli were 0.23 µM for (di-(4-chlorobenzyl)) caffeate (13) and 0.29 µM for diphenylmethyl caffeate (10) and all were less active against the Staphylococcus aureus strain. Preliminary quantitative structure-activity relationship (QSAR) analyses confirmed that certain structural characteristics, such as a median linear carbon chain and the presence of electron withdrawal substituents at the para position of the aromatic ring, help potentiate antibacterial activity.

Is caffeic acid phenethyl ester more protective than doxycycline in experimental periodontitis?

BACKGROUND AND OBJECTIVES

Host modulation therapies (anti-inflammatory drugs, bone-stimulating agents, anti-proteinase etc.) target the inhibition or stabilization of tissue breakdown. The aim of the present study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) and/or low dose doxycycline (LDD) administrations on alveolar bone loss (ABL), serum cytokines and gingival apoptosis, as well as the levels of oxidants and anti-oxidants in rats with ligature-induced periodontitis.

MATERIAL AND METHODS

The animals were randomly divided into five groups: Group C (periodontally healthy), Group PC (Periodontitis+CAPE), Group PD (Periodontitis+LDD), Group PCD (Periodontitis+CAPE+LDD), Group P (Periodontitis). Experimental periodontitis was induced for 14days. Levels of ABL, and the serum cytokines, interleukin (IL)-1 β, IL-6, tumor necrosis factor-α (TNF-α) and IL-10 were assessed as were the levels of the oxidants and anti-oxidants, malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase (GSH-Px), and levels of gingival apoptosis.

RESULTS

The lowest ABL levels was evident in the PC group, among the experimental groups. There was also less inflammatory infiltration in the PC group than the PD group. IL-1β, IL-6, and IL-10 were lower in the PC group and higher in the P group in comparison to the levels in the other experiment groups. TNF-α levels in the PD group were higher than levels in the PC and PCD groups. The PC and PCD groups did not differ from the C group in regard to MDA levels. The highest GSH-Px level was found in the PC group. Gingival apoptosis in the PC group was not only lower than the PD and PCD groups, but also lower than in the C group.

CONCLUSION

The present study suggests that CAPE has more anti-inflammatory, anti-oxidant and anti-apoptotic effects than LDD, with no additive benefits of a CAPE+LDD combination being evident in rats with periodontitis.

Inhibitory Effect of Methyl 2-(4'-Methoxy-4'-oxobutanamide) Benzoate from Jerusalem Artichoke (Helianthus tuberosus) on the Inflammatory Paracrine Loop between Macrophages and Adipocytes

The interaction between macrophages and adipocytes is known to aggravate inflammation of the adipose tissue, leading to decreased insulin sensitivity. Hence, attenuation of the inflammatory paracrine loop between macrophages and adipocytes is deemed essential to ameliorate insulin resistance and diabetes mellitus type 2. Methyl 2-(4'-methoxy-4'-oxobutanamide) benzoate (compound 1), a newly isolated compound from Jerusalem srtichoke (JA), has not been biologically characterized yet. Here, we investigated whether JA-derived compound 1 attenuates the inflammatory cycle between RAW 264.7 macrophages and 3T3-L1 adipocytes. Compound 1 suppressed the inflammatory response of RAW 264.7 cells to lipopolysaccharide through decreased secretion of IL-1β, IL-6, and TNF-α. Moreover, the mRNA expression of TNF-α, IL-6, IL-1β, MCP-1, and Rantes and MAPK pathway activation in 3T3-L1 adipocytes, incubated in macrophage-conditioned media, were inhibited. These findings suggest an anti-inflammatory effect of a newly extracted compound against adipose tissue inflammation and insulin resistance.

Aqueous Extract of Clerodendranthus spicatus Exerts Protective Effect on UV-Induced Photoaged Mice Skin

Clerodendranthus spicatus (Thunb.) C.Y.Wu (CS) is commonly used to treat kidney diseases in traditional Chinese medicine for its prominent anti-inflammatory effect and nourishing function to kidneys. In this study, aqueous extract of CS was assessed for its protective effect on UV-induced skin damage of mice. The chemical compositions of CS aqueous extract were determined by HPLC-ESI-MS/MS, in which 10 components were identified. During the experimental period, CS (0.9, 1.8, and 3.6 g/mL) was externally applied to shaved dorsal skins of mice prior to UV irradiation, daily for ten weeks. The results presented that CS (3.6 g/mL) apparently improved photodamaged skin appearance such as erythema, edema, and coarseness. The abnormal epidermal thickening was significantly reduced, and the dermal structures became more complete. The underlying protective mechanisms were associated with improving antioxidant enzymes activities including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), downregulating inflammatory cytokines (IL-1β, IL-6, TNF-α, COX-2, and PGE₂) expressions, recovering collagen density, and reducing matrix metalloproteinases productions. Sun protection factor of CS (3.6 g/mL) was 16.21 ± 0.03. Our findings for the first time demonstrated that CS had therapeutic effect on the photoaged skin. The results indicated that CS is a potential agent for photoprotective cosmetics.

Inhibitory Activities of Phenolic Compounds Isolated from Adina rubella Leaves Against 5α-Reductase Associated with Benign Prostatic Hypertrophy

Adina rubella Hance (AR), a plant native to Korea, has been used as traditional medicine for dysentery, eczema, intoxication, and external hemorrhages. Previous phytochemical studies of AR have reported several components, including terpenoids, phenolics, and alkaloids. The current study evaluated the anti-oxidative and anti-inflammatory activities and 5α-reductase inhibition of isolated compounds of AR leaves to find a potential therapeutic agent for benign prostatic hypertrophy (BPH). Repeated chromatographic isolation of an 80% acetone extract of AR leaves yielded seven phenolic compounds: caffeic acid (1), chlorogenic acid (2), methyl chlorogenate (3), quercetin-3-rutinoside (4), kaempferol-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (5), hyperoside (6), and grandifloroside (7). Compound 7 is a novel compound in AR. Caffeoyl derivatives 1–3 and 7 showed good anti-oxidative activities. In particular, caffeic acid (1) and grandifloroside (7) showed potent anti-inflammatory activities, and 7 also exhibited potent inhibitory activity against TNF-α and 5α-reductase. Our results show that the extract and grandifloroside (7) from leaves of AR might be developed as a source of potent anti-oxidative and anti-inflammatory agents and therapeutic agent for BPH.

Neuroprotective effect of caffeic acid phenethyl ester in 3-nitropropionic acid-induced striatal neurotoxicity

Caffeic acid phenethyl ester (CAPE), derived from honeybee hives, is a bioactive compound with strong antioxidant activity. This study was designed to test the neuroprotective effect of CAPE in 3-nitropropionic acid (3NP)-induced striatal neurotoxicity, a chemical model of Huntington's disease (HD). Initially, to test CAPE's antioxidant activity, a 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) antioxidant assay was employed, and CAPE showed a strong direct radical-scavenging eff ect. In addition, CAPE provided protection from 3NP-induced neuronal cell death in cultured striatal neurons. Based on these observations, the in vivo therapeutic potential of CAPE in 3NP-induced HD was tested. For this purpose, male C57BL/6 mice were repeatedly given 3NP to induce HD-like pathogenesis, and 30 mg/kg of CAPE or vehicle (5% dimethyl sulfoxide and 95% peanut oil) was administered daily. CAPE did not cause changes in body weight, but it reduced mortality by 29%. In addition, compared to the vehicle-treated group, robustly reduced striatal damage was observed in the CAPE-treated animals, and the 3NP-induced behavioral defi cits on the rotarod test were signifi cantly rescued after the CAPE treatment. Furthermore, immunohistochemical data showed that immunoreactivity to glial fibrillary acidic protein (GFAP) and CD45, markers for astrocyte and microglia activation, respectively, were strikingly reduced. Combined, these data unequivocally indicate that CAPE has a strong antioxidant eff ect and can be used as a potential therapeutic agent against HD.

Luteolin is a bioflavonoid that attenuates adipocyte-derived inflammatory responses via suppression of nuclear factor-κB/mitogen-activated protein kinases pathway

Background:

Inflammation of adipocytes has been a therapeutic target for treatment of obesity and metabolic disorders which cause insulin resistance and hence lead to type II diabetes. Luteolin is a bioflavonoid with many beneficial properties such as antioxidant, antiproliferative, and anti-cancer.

Objectives:

To elucidate the potential anti-inflammatory response and the underlying mechanism of luteolin in 3T3-L1 adipocytes.

Materials and Methods:

We stimulated 3T3-L1 adipocytes with the mixture of tumor necrosis factor-α, lipopolysaccharide, and interferon-γ (TLI) in the presence or absence of luteolin. We performed Griess’ method for nitric oxide (NO) production and measure mRNA and protein expressions by real-time polymerase chain reaction and western blotting, respectively.

Results:

Luteolin opposed the stimulation of inducible nitric oxide synthase and NO production by simultaneous treatment of adipocytes with TLI. Furthermore, it reduced the pro-inflammatory genes such as cyclooxygenase-2, interleukin-6, resistin, and monocyte chemoattractant protein-1. Furthermore, luteolin improved the insulin sensitivity by enhancing the expression of insulin receptor substrates (IRS1/2) and glucose transporter-4 via phosphatidylinositol-3K signaling pathway. This inhibition was associated with suppression of Iκ-B-α degradation and subsequent inhibition of nuclear factor-κB (NF-κB) p65 translocation to the nucleus. In addition, luteolin blocked the phosphorylation of ERK1/2, c-Jun N-terminal Kinases and also p38 mitogen-activated protein kinases (MAPKs).

Conclusions:

These results illustrate that luteolin attenuates inflammatory responses in the adipocytes through suppression of NF-κB and MAPKs activation, and also improves insulin sensitivity in 3T3-L1 cells, suggesting that luteolin may represent a therapeutic agent to prevent obesity-associated inflammation and insulin resistance.

Transient blocking of NK cell function with small molecule inhibitors for helper dependant adenoviral vector-mediated gene delivery

One major challenge in gene therapy is the host immune responses against viral vectors. Previous studies indicate the involvement of NK cells in stunted gene expression in viral vector mediated gene therapy. To understand the problem of the immune responses, we have developed an in-vitro co-culture system with human NK cell line, macrophages and airway epithelial cells. We showed that small molecule blockers, CAPE and ruxolitinib, for NF-κB and JAK-STAT pathways, respectively, significantly inhibited cytokine secretion by macrophages. When NK cells are co-cultured with helper-dependent adenoviral (HD-Ad) vector activated macrophages, IFN-γ cytokine expression by NK cells increased significantly, which was inhibited effectively by ruxolitinib and CAPE, and there was an additive effect when both inhibitors were used. We demonstrated that NK cells activated by cytokines produced by HD-Ad-activated macrophages kill HD-Ad vector transduced bronchial epithelial cells. This cell killing activity was significantly reduced by CAPE and ruxolitinib. Combination of these two inhibitors had an additive effect on inhibiting NK cell mediate killing of gene transduced cells. Transient inhibition of NK cell response at its peak may enhance sustained gene expression. Our data suggest that combination of CAPE and ruxolitinib may help in protecting gene transduced airway epithelial cells to prolong transgene expression.

Inhibitory effects of hydroxylated cinnamoyl esters on lipid absorption and accumulation

Obesity is a risk factor associated with several lifestyle-related diseases, for example, diabetes, high blood pressure, hyperlipidemia and cancer. Caffeic acid 2-phenylethyl ester (CAPE, 1), a naturally-occurring compound found in various plants and propolis, which exhibits anti-inflammatory, immunomodulatory and cytotoxic activities and inhibits 3T3-L1 differentiation to adipocytes. As part of our efforts to moderate lifestyle-related diseases, we synthesized analogs of 1 and studied their effects on pancreatic lipase activities, lipid absorption, and 3T3-L1 differentiation. We found that catechols 1-4 show inhibitory activities against pancreatic lipase in a dose-dependent manner in vitro. Compounds 1-3 proved to be more potent inhibitors of pancreatic lipase than 5, 6, 8, and 9, which have one hydroxyl group, respectively. Compound 7 has three aromatic hydroxyl groups and restrains greater lipase inhibitory activity than the other compounds. In addition, 7 and 3 significantly suppress a rise in blood triglyceride (TG) levels in mice given corn oil orally. Furthermore, 2 and 3 are more potent at preventing 3T3-L1 differentiation (lipid accumulation) than 1, while 7 is more potent than 3, 8, and 9 in these assays. Compounds 2, 3, and 7 inhibit lipid absorption and accumulation, with new compound 7 being the most potent. These results indicate that 7 may have potential benefits as a health agent with anti-obesity properties.

Therapeutic potential of caffeic acid phenethyl ester and its anti-inflammatory and immunomodulatory effects (Review)

Caffeic acid phenethyl ester (CAPE), a naturally occurring compound isolated from propolis extract, has been reported to have a number of biological and pharmacological properties, exerting antioxidant, anti-inflammatory, anticarcinogenic, antibacterial and immunomodulatory effects. Recent in vivo and in vitro study findings have provided novel insights into the molecular mechanisms involved in the anti-inflammatory and immunomodulatory activities of this natural compound. CAPE has been reported to have anti-inflammatory properties involving the inhibition of certain enzyme activities, such as xanthine oxidase, cyclooxygenase and nuclear factor-κB (NF-κB) activation. Since inflammation and immune mechanisms play a crucial role in the onset of several inflammatory diseases, the inhibition of NF-κB represents a rationale for the development of novel and safe anti-inflammatory agents. The primary goal of the present review is to highlight the anti-inflammatory and immunomodulatory activities of CAPE, and critically evaluate its potential therapeutic effects.

Propolis: A Complex Natural Product with a Plethora of Biological Activities That Can Be Explored for Drug Development

The health industry has always used natural products as a rich, promising, and alternative source of drugs that are used in the health system. Propolis, a natural resinous product known for centuries, is a complex product obtained by honey bees from substances collected from parts of different plants, buds, and exudates in different geographic areas. Propolis has been attracting scientific attention since it has many biological and pharmacological properties, which are related to its chemical composition. Several in vitro and in vivo studies have been performed to characterize and understand the diverse bioactivities of propolis and its isolated compounds, as well as to evaluate and validate its potential. Yet, there is a lack of information concerning clinical effectiveness. The goal of this review is to discuss the potential of propolis for the development of new drugs by presenting published data concerning the chemical composition and the biological properties of this natural compound from different geographic origins.

A Rapid and Practical Catalytic Esterification for the Preparation of Caffeic Acid Esters

A convenient and practical catalytic method for the preparation of caffeic acid esters is reported. This esterification was carried out with high efficiency in the presence of ytterbium triflate in nitromethane without any other auxiliary reagents. The wide scope of application and especially the higher reactivity and more convenient procedure than previous methods make it a valuable application for the synthesis of caffeic acid esters and other cinnamic acid esters.

Caffeic Acid phenethyl ester: consequences of its hydrophobicity in the oxidative functions and cytokine release by leukocytes

Numerous anti-inflammatory properties have been attributed to caffeic acid phenethyl ester (CAPE), an active component of propolis. NADPH oxidases are multienzymatic complexes involved in many inflammatory diseases. Here, we studied the importance of the CAPE hydrophobicity on cell-free antioxidant capacity, inhibition of the NADPH oxidase and hypochlorous acid production, and release of TNF-α and IL-10 by activated leukocytes. The comparison was made with the related, but less hydrophobic, caffeic and chlorogenic acids. Cell-free studies such as superoxide anion scavenging assay, triene degradation, and anodic peak potential (E_pa) measurements showed that the alterations in the hydrophobicity did not provoke significant changes in the oxidation potential and antiradical potency of the tested compounds. However, only CAPE was able to inhibit the production of superoxide anion by activated leukocytes. The inhibition of the NADPH oxidase resulted in the blockage of production of hypochlorous acid. Similarly, CAPE was the more effective inhibitor of the release of TNF-α and IL-10 by Staphylococcus aureus stimulated cells. In conclusion, the presence of the catechol moiety and the higher hydrophobicity were essential for the biological effects. Considering the involvement of NADPH oxidases in the genesis and progression of inflammatory diseases, CAPE should be considered as a promising anti-inflammatory drug.

Synthesis of caffeic acid phenethyl ester derivatives, and their cytoprotective and neuritogenic activities in PC12 cells

Twenty-one caffeic acid phenethyl ester (CAPE) derivatives were synthesized, and characterized by IR, HR-MS, (1)H and (13)C NMR analyses. All compounds were evaluated for their cytoprotective effects against H2O2-induced cytotoxicity and neuritogenic activities in the neurite outgrowth in PC12 cells. Compounds 1 and 20 exhibited stronger cytoprotective activities than their parent compound CAPE at 4 nM. Compounds 1, 4, 12 and 13 showed potential neuritogenic activities at 0.5 nM, while compounds 19 and 20 induced neurite outgrowth at 10 nM. The results from this study suggested that CAPE and its derivatives may be potential functional food ingredients for the prevention of neurodegenerative diseases.

Caffeic acid phenethyl ester attenuates pro-inflammatory and fibrogenic phenotypes of LPS-stimulated hepatic stellate cells through the inhibition of NF-κB signaling

Hepatic stellate cells (HSCs) are the major cell type involved in liver fibrosis. Lipopolysaccharide (LPS)-mediated signaling through Τoll-like receptor 4 (TLR4) in HSCs has been identified as a key event in liver fibrosis, and as the molecular link between inflammation and liver fibrosis. In this study, we investigated the effects of caffeic acid phenethyl ester (CAPE), one of the main medicinal components of propolis, on the pro-inflammatory and fibrogenic phenotypes of LPS-stimulated HSCs. HSCs from rats were isolated and cultured in Dulbecco's modified Eagle's medium (DMEM). Following treatment with LPS, HSCs showed a strong pro-inflammatory phenotype with an upregulation of pro-inflammatory mediators, and a fibrogenic phenotype with enhanced collagen synthesis, mediated by transforming growth factor-β1 (TGF-β1). CAPE significantly and dose-dependently reduced LPS-induced nitrite production, as well as the transcription and protein synthesis of monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS), as determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blotting and enzyme-linked immunosorbent assays (ELISA). CAPE further reduced the TGF-β1-induced transcription and translation (protein synthesis) of the gene coding for collagen type I α1 (col1A1), in LPS-stimulated HSCs. Following LPS stimulation, the phosphorylation of the nuclear factor-κB (NF-κB) inhibitor IκBα and consequently, the nuclear translocation of NF-κB, were markedly increased in the HSCs, and these changes were reversed by pre-treatment with CAPE. In conclusion, CAPE attenuates the pro-inflammatory phenotype of LPS-stimulated HSCs, as well as the LPS-induced sensitization of HSCs to fibrogenic cytokines by inhibiting NF-κB signaling. Our results provide new insight into the treatment of hepatic fibrosis through regulation of the TLR4 signaling pathway.

Caffeic acid phenethyl ester suppresses oxidative stress in 3T3-L1 adipocytes

The generation of oxidative stress, characterized by enhanced reactive oxygen species (ROS) formation, has been found in obesity. ROS production was increased during the differentiation of 3T3-L1 cells into adipocytes. We previously reported that caffeic acid phenethyl ester (CAPE) suppresses 3T3-L1 differentiation to adipocytes through the inhibition of peroxisome proliferator-activated receptor γ. In this study, the preventive effect of CAPE on oxidative stress in 3T3-L1 cells was observed. The results were as follows: (1) ROS production during 3T3-L1 cell differentiation to adipocytes was significantly (p < 0.05) suppressed by CAPE treatment in a concentration-dependent manner, (2) with CAPE treatment, the extracellular superoxide dismutase mRNA expression level significantly increased, but the NOX4 mRNA expression level did not change, and (3) CAPE treatment significantly increased superoxide dismutase (SOD) activity in 3T3-L1 cells. From these results, we suggest that the increased oxidative stress in 3T3-L1 differentiation to adipocytes is attenuated by CAPE treatment. This attenuation may be partly caused by increased SOD production.

Caffeic acid phenethyl ester, a promising component of propolis with a plethora of biological activities: a review on its anti-inflammatory, neuroprotective, hepatoprotective, and cardioprotective effects

Caffeic acid phenethyl ester (CAPE) is an important active component of honey bee propolis that possesses a plethora of biological activities. Propolis is used safely in traditional medicine as a dietary supplement for its therapeutic benefits. This review highlights the recently published data about CAPE bioavailability, anti-inflammatory, neuroprotective; hepatoprotective and cardioprotective activities. CAPE showed promising efficacy both in vitro and in vivo studies in animal models with minimum adverse effects. Its effectiveness was demonstrated in multiple target organs. Despite this fact, it has not been yet investigated as a protective agent or a potential therapy in humans. Investigation of CAPE efficacy in clinical trials is strongly encouraged to elucidate its therapeutic benefit for different human diseases after performing full preclinical toxicological studies and gaining more insights into its pharmacokinetics.