Anti-inflammatory effect of phenethyl isothiocyanate, an active ingredient of Raphanus sativus Linne

Phenethyl isothiocyanate (PEITC) is an active ingredient of Raphanus sativus Linne (Cruciferae). However, regulatory mechanism of PEITC involved in caspase-1 signalling has not been fully elucidated in mast cells. First, PEITC inhibited the production of IL-6 through the inhibition of caspase-1/receptor-interacting protein 2, followed by regulation of NF-κB/IκBα pathway or p38 and extracellular signal-regulated kinase mitogen-activated protein kinases. Second, PEITC inhibited the IL-1β production through the inhibition of caspase-1 proteolytic activity. Overall, these results provide a proof that PEITC can inhibit the inflammatory reactions by two distinct pathways in mast cells and open new perspectives to pharmacologically manipulate the expression and production of IL-6 and IL-1β by molecules acting on the caspase-1 pathway.     

Phenethyl isothiocyanate suppresses nitric oxide production via inhibition of phosphoinositide 3‐kinase/Akt‐induced IFN‐γ secretion in LPS‐activated peritoneal macrophages

Phenethyl isothiocyanate (PEITC), a constituent of many cruciferous vegetables, is well known to have versatile physiological activities, including chemopreventive effects. On the other hand, its anti‐inflammatory effects are poorly reported. Nitric oxide (NO) is associated with a wide variety of inflammatory diseases. In this study, we investigated the effects of PEITC on NO production in LPS‐activated peritoneal macrophages from ICR mice. The signaling pathway of LPS‐induced NO production was examined using neutralizing antibodies [anti‐interferon (IFN)‐γ and anti‐interleukin (IL‐12)] and specific protein kinase inhibitors, as well as others. The activity of PEITC toward NOx production was assessed in mice that received LPS via intraperitoneal administration. The neutralizing antibody of anti‐IFN‐γ, but not anti‐IL‐12, suppressed LPS‐induced NO production by 90%. LY294002, a specific inhibitor of phosphoinositide‐3‐kinase, suppressed Akt and IFN‐γ mRNA expression up‐regulated by LPS, whereas PEITC exhibited a similar inhibition profile. Furthermore, oral administration of PEITC significantly suppressed the serum concentration of NOx in ICR mice. Our results suggest that PEITC suppresses LPS‐induced NO production via inhibition of Akt activation and the resultant decrease in expression of IFN‐γ. This is one of the first reports to demonstrate a marked anti‐inflammatory effect of PEITC following its oral administration.     

Effect of orally administered phenethyl isothiocyanate on hepatic gene expression in rats

Scope: Phenethyl isothiocyanate (PEITC) is a constituent of cruciferous vegetables that has demonstrated cancer preventive activity in a number of cancer models including lung, prostate, and breast cancer. Our objective was to examine the effects of the oral administration of PEITC for 7 days on the hepatic expression of genes important in drug metabolism and toxicity in Sprague Dawley rats. The liver is the major site for the metabolism of various xenobiotics and carcinogens, and determining the effects of PEITC on the gene expression of hepatic enzymes may provide insight into mechanisms underlying the cancer preventive activity of PEITC. Methods and results: Using a microarray containing 282 genes, we observed that PEITC significantly up‐regulated UDP‐glucuronosyltransferase UGT1A6 and strongly down‐regulated nicotinamide N‐methyltransferase (NNMT). We also confirmed the down‐regulation of NNMT by real‐time quantitative RT‐PCR. Other genes that were significantly up‐regulated were the drug metabolizing enzyme cyp2b15, the anti‐apoptotic gene bcl2l2, and the stress regulators Gadd45b, Dnajb9, Dnajb5 and Hspb1. Conclusion: Our results indicate new targets that may be important in the mechanisms of the anticancer effects of PEITC. Of particular significance was the down‐regulation of NNMT which may represent a new target for the treatment of a variety of cancers.     

Phenethyl isothiocyanate sensitizes human cervical cancer cells to apoptosis induced by cisplatin

Scope: Naturally‐occurring chemopreventive agent phenethyl isothiocyanate (PEITC), derived primarily from watercress, has been shown to inhibit cell growth and induce apoptosis in cancer cells. In this study, we examined the potential of PEITC in enhancing cisplatin‐induced apoptosis in cervical cancer cells and its mechanisms. Methods and results: HeLa cells were exposed to PEITC, cisplatin or both. Pretreatment of cells with PEITC strongly enhanced cisplatin‐induced cytotoxicity. PEITC activated the mitogen‐activated protein kinases, including c‐Jun N‐terminal kinase (JNK), extracellular signal‐related kinase (ERK), and p38. Caspase‐3 activity assay demonstrated that the synergistic induction of apoptosis was significantly attenuated by MEK1/2 inhibitor U0126, but not by JNK or p38 inhibitor, suggesting that ERK activation is responsible for the synergistic effect. We found that NF‐κB signaling pathway is not involved in the synergistic effect. Sulforaphane and benzyl isothiocyanate, two other members of the isothiocyanate family, also sensitize HeLa cells to apoptosis induced by cisplatin. Furthermore, we found that the synergistic effect was also observed in cervical cancer C33A and breast cancer MCF‐7 cells but not in normal mammary epithelial MCF‐10A cells. Finally, we demonstrated that Noxa induction was associated with apoptosis induced by PEITC plus cisplatin. Conclusion: Taken together, this study shows that PEITC can sensitize cancer cells to apoptosis induced by cisplatin and this effect is mediated through ERK activation, suggesting the potential of PEITC to be used as an adjuvant with cisplatin in combination therapeutic treatments.     

Phenethyl isothiocyanate inhibits hypoxia-induced accumulation of HIF-1α and VEGF expression in human glioma cells

Phenethyl isothiocyanate (PEITC), a natural dietary isothiocyanate, inhibits angiogenesis but the molecular mechanisms that underlie this effect are not known. In this study, under hypoxic conditions (1% O₂), we examined the effect of PEITC on the intracellular level of the hypoxia inducible factor (HIF-1α) and extracellular level of the vascular endothelial growth factor (VEGF) in a variety of human cancer cell lines. Surprisingly, we observed that PEITC suppressed the HIF-1α accumulation during hypoxia in human glioma U87, human prostate cancer DU145, colon cancer HCT116, liver cancer HepG2, and breast cancer SkBr3 cells. PEITC treatment also significantly reduced the hypoxia-induced secretion of VEGF. Suppression of HIF-1α accumulation during treatment with PEITC in hypoxia was related to PI3K and MAPK pathways. Taken together, these results suggest that PEITC inhibits the HIF-1α expression through inhibiting the PI3K and MAPK signalling pathway and provide a new insight into a potential mechanism of the anticancer properties of PEITC.     

Phenethyl isothiocyanate inhibits STAT3 activation in prostate cancer cells

This study was undertaken to investigate the mechanism by which phenethyl isothiocyanate (PEITC), a natural compound from cruciferous vegetables, exhibits antitumor effect on prostate cancer cells. Cell proliferation, cell cycle, Western blot, gene transfer, and reporter assays were used to test the effects of PEITC on the growth and IL6/JAK/STAT3 pathway in prostate cancer. The result showed that PEITC significantly inhibited DU145 cell proliferation in a dose‐dependent manner and induced the cell arrest at G2‐M phase. PEITC inhibited both constitutive and IL‐6‐induced STAT3 activity in DU145 cells. IL‐6‐stimulated phosphorylation of JAK2, an STAT3 upstream kinase, was also attenuated by PEITC. Moreover, an antioxidant reagent, N‐acetyl‐L ‐cysteine (NAC) which suppresses reactive oxygen species (ROS) generation, reversed the early inhibitory effects of PEITC on cell proliferation, constitutive or IL‐6‐mediated JAK‐STAT3 phosphorylation in PCa cells. Taken together, our data demonstrated that PEITC can inhibit the activation of the JAK‐STAT3 signal‐cascade in prostate cancer cells and the underlying mechanism may be partially involved with blocking cellular ROS production during the early stage of the signaling activation by IL‐6.     

Nutritional Sources and Anticancer Potential of Phenethyl Isothiocyanate: Molecular Mechanisms and Therapeutic Insights

Phenethyl isothiocyanate (PEITC), a compound derived from cruciferous vegetables, has garnered attention for its anticancer properties. This review synthesizes existing research on PEITC, focusing on its mechanisms of action in combatting cancer. PEITC has been found to be effective against various cancer types, such as breast, prostate, lung, colon, and pancreatic cancers. Its anticancer activities are mediated through several mechanisms, including the induction of apoptosis (programmed cell death), inhibition of cell proliferation, suppression of angiogenesis (formation of new blood vessels that feed tumors), and reduction of metastasis (spread of cancer cells to new areas). PEITC targets crucial cellular signaling pathways involved in cancer progression, notably the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB), Protein Kinase B (Akt), and Mitogen-Activated Protein Kinase (MAPK) pathways. These findings suggest PEITC's potential as a therapeutic agent against cancer. However, further research is necessary to determine the optimal dosage, understand its bioavailability, and assess potential side effects. This will be crucial for developing PEITC-based treatments that are both effective and safe for clinical use in cancer therapy.     

Suppression of thymic stromal lymphopoietin production by rutin in mast cells

Thymic stromal lymphopoietin (TSLP) is a key player in allergic diseases such as asthma and atopic dermatitis. Rutin (RU), a non-nutritive component of many foods, possesses anti-inflammatory, hepatoprotective, and anti-tumour effects. We investigated how RU inhibits the production of TSLP in human mast cell line (HMC-1) cells. RU inhibited the production and mRNA expression of TSLP in HMC-1 cells. The maximal inhibition rate of TSLP production by RU (50 μM) was 56.25 ± 2.81%. Nuclear factor-κB luciferase activity induced by phorbol myristate acetate plus A23187 was inhibited by RU. In the activated HMC-1 cells, the activation of caspase-1 was increased, whereas the activation of caspase-1 was decreased by pre-treatment with RU. Finally, RU inhibited the numbers of TSLP-positive mast cells in lesions of PMA-induced ear oedema model. These results suggest that RU would be helpful for the treatment of inflammatory and atopic diseases through the inhibition of TSLP.     

Repeated oral administration modulates the pharmacokinetic behavior of the chemopreventive agent phenethyl isothiocyanate in rats

The principal objective of this study was to evaluate whether repeated oral administration influences the pharmacokinetic behavior of the chemopreventive agent phenethyl isothiocyanate (PEITC) in rat. Animals were treated orally with 0.5, 1.0 and 5.0 mg/kg of the isothiocyanate for 4 days, and plasma levels at various times post‐administration were determined by LC/MS after the first and last day. To determine absolute bioavailability, a group of animals was treated with a single (0.5 mg/kg) intravenous dose of PEITC. Following single oral dose administration, PEITC was rapidly absorbed, peak plasma concentrations being attained within the hour, and achieved an absolute bioavailability of 77%, but displayed dose‐dependent pharmacokinetics, with bioavailability decreasing and clearance increasing moderately with dose; C_max values did not rise proportionately to the dose and volume of distribution increased. At the higher doses of 1.0 and 5.0 mg/kg, repeated administration led to higher PEITC plasma C_max concentrations and decreased plasma clearance of the isothiocyanate leading to enhanced bioavailability.     

Polygonum viviparum L. inhibits the lipopolysaccharide‐induced inflammatory response in RAW264.7 macrophages through haem oxygenase‐1 induction and activation of the Nrf2 pathway

BACKGROUND: Polygonum viviparum L. (PV) is a member of the family Polygonaceae and is widely distributed in high‐elevation areas. It is used as a folk remedy to treat inflammation‐related diseases. This study was focused on the anti‐inflammatory response of PV against lipopolysaccharide (LPS)‐induced inflammation in RAW264.7 macrophages. RESULTS: Treatment with PV did not cause cytotoxicity at 0–50 µg mL^?1 in RAW264.7 macrophages, and the IC₅₀ value was 270 µg mL^?1. PV inhibited LPS‐stimulated nitric oxide (NO), prostaglandin (PG)E₂, interleukin (IL)‐1β and tumour necrosis factor (TNF)‐α release and inducible NO synthase (iNOS) and cyclooxygenase (COX)‐2 protein expression. In addition, PV suppressed the LPS‐induced p65 expression of nuclear factor (NF)‐κB, which is associated with the inhibition of IκB‐α degradation. These results suggest that, among mechanisms of the anti‐inflammatory response, PV inhibits the production of NO and these cytokines by down‐regulating iNOS and COX‐2 gene expression. Furthermore, PV can induce haem oxygenase (HO)‐1 protein expression through nuclear factor E2‐related factor 2 (Nrf2) activation. A specific inhibitor of HO‐1, zinc(II) protoporphyrin IX, inhibited the suppression of iNOS and COX‐2 expression by PV. CONCLUSION: These results suggest that PV possesses anti‐inflammatory actions in macrophages and works through a novel mechanism involving Nrf2 actions and HO‐1. Thus PV could be considered for application as a potential therapeutic approach for inflammation‐associated disorders. © 2012 Society of Chemical Industry     

Dicaffeoylquinic acids in Yerba mate (Ilex paraguariensis St. Hilaire) inhibit NF-κB nucleus translocation in macrophages and induce apoptosis by activating caspases-8 and -3 in human colon cancer cells

Scope : The biological functions of caffeoylquinic acid (CQA) derivatives from various plant sources have been partially elucidated. The objectives were to isolate and purify diCQAs from Yerba mate tea leaves and assess their anti‐inflammatory and anti‐cancer capabilities in vitro and explore their mechanism of action. Methods and results : Methanol extracts of dried mate leaves were resolved by flash chromatography and further purified resulting in two fractions one containing 3,4‐ and 3,5‐diCQAs and the other 4,5‐diCQA with NMR‐confirmed structures. Both fractions inhibited LPS‐induced RAW 264.7 macrophage inflammation by suppressing nitric oxide/inducible nitric oxide and prostaglandin E₂/cyclooxygenase‐2 pathways through inhibiting nucleus translocation of Nuclear factor κB subunits, p50 and p65. The diCQA fractions inhibited Human colon cancer cells CRL‐2577 (RKO) and HT‐29 cell proliferation by inducing apoptosis in a time‐ and concentration‐dependent manner, but did not affect the protein levels of p21, p27, p53, and Bax:Bcl‐2 ratio in RKO cells. In HT‐29 cells, however, the diCQA fractions increased Bax:Bcl‐2 ratio. The diCQA fractions increased the activation of caspase‐8 leading to cleavage of caspase‐3 in both RKO and HT‐29 colon cancer cells. Conclusion : The results suggest that diCQAs in Yerba mate could be potential anti‐cancer agents and could mitigate other diseases also associated with inflammation.     

Sarcodon aspratus Extract Ameliorates Dextran Sulfate Sodium‐Induced Colitis in Mouse Colon and Mesenteric Lymph Nodes

Mushrooms have been previously investigated for their immune‐modulating and anti‐inflammatory properties. We examined whether the anti‐inflammatory properties of Sarcodon aspratus ethanol extract (SAE) could elicit protective effects against dextran sulfate sodium (DSS)‐induced colitis in vivo. Male C57/BL6 mice were randomly assigned to 1 of 4 treatment groups: control (CON; n = 8), DSS‐treated (DSS; n = 9), DSS+SAE at 50 mg/kg BW (SAE50; n = 8), and DSS+SAE at 200 mg/kg BW groups (SAE200; n = 9). DSS treatment induced significant weight loss, which was significantly recovered by SAE200. Although SAE did not affect DSS‐mediated reductions in colon length, it improved diarrhea and rectal bleeding induced by DSS. SAE at 200 mg/kg BW significantly attenuated IL‐6 and enhanced IL‐10 expression in mesenteric lymph nodes (MLN), and significantly reduced IL‐6 levels in splenocytes. SAE200 also significantly attenuated DSS‐induced increase in IL‐6 and IL‐1β, and reductions in IL‐10 in colon tissue. High levels of SAE were also observed to significantly decrease inflammatory COX‐2 expression that was upregulated by DSS in mice colon. These findings may have relevance for novel therapeutic strategies to mitigate inflammatory bowel disease‐relevant inflammatory responses, via the direct and indirect anti‐inflammatory activity of SAE. We also found that SAE harbors significant quantities of total fiber and β‐glucan, suggesting a possible role for these components in protection against DSS‐mediated colitis.     

Ginger Extract Suppresses Inflammatory Response and Maintains Barrier Function in Human Colonic Epithelial Caco‐2 Cells Exposed to Inflammatory Mediators

The beneficial effects of ginger in the management of gastrointestinal disturbances have been reported. In this study, the anti‐inflammatory potential of ginger extract was assessed in a cellular model of gut inflammation. In addition, the effects of ginger extract and its major active compounds on intestinal barrier function were evaluated. The response of Caco‐2 cells following exposure to a mixture of inflammatory mediators [interleukin [IL]‐1β, 25 ng/mL; lipopolysaccharides [LPS], 10 ng/mL; tumor necrosis factor [TNF]‐α, 50 ng/mL; and interferon [INF]‐γ, 50 ng/mL] were assessed by measuring the levels of secreted IL‐6 and IL‐8. In addition, the mRNA levels of cyclooxygenase‐2 and inducible nitric oxide synthase were measured. Moreover, the degree of nuclear factor (NF)‐κB inhibition was examined, and the intestinal barrier function was determined by measuring the transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)‐dextran transfer. It was observed that ginger extract and its constituents improved inflammatory responses by decreasing the levels of nitrite, PGE2, IL‐6, and IL‐8 via NF‐κB inhibition. The ginger extract also increased the TEER and decreased the transfer of FITC‐dextran from the apical side of the epithelium to the basolateral side. Taken together, these results show that ginger extract may be developed as a functional food for the maintenance of gastrointestinal health.     

Dietary grape seed extract ameliorates symptoms of inflammatory bowel disease in IL10‐deficient mice

Grape seed extract (GSE) is a by‐product of the wine industry, with abundant polyphenolic compounds known for their anti‐inflammatory and anti‐oxidative effects. Using IL10‐deficient mice (IL10KO), here we showed that GSE (1% of dry feed weight) ameliorated inflammatory bowel disease indices, increased colonic goblet cell numbers and decreased myeloperoxidase levels in the large intestine. Concomitantly, GSE supplementation attenuated inflammation, decreased the expression of pore forming tight junction protein claudin2, and increased levels of Lactobacilli and Bacteroides in the gut microbiota of IL10KO mice. In summary, our study shows that GSE has protective roles on inflammatory bowel disease through altering gut inflammation, tight junction protein expression, and gut microbiota composition.     

Anti-inflammatory activities of aqueous extract of Mesona procumbens in experimental mice

BACKGROUND: Mesona procumbens is consumed as a herbal drink and jelly‐type dessert in Taiwan. The aim of this study was to determine the mechanism of anti‐inflammatory activities of the aqueous extract of M. procumbens (AMP) using the λ‐carrageenin (Carr)‐induced mouse paw oedema model. The fingerprint chromatogram of AMP was obtained by high‐performance liquid chromatography (HPLC) analysis. To investigate the anti‐inflammatory mechanism of AMP, the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) and the level of malondialdehyde (MDA) in paw oedema were monitored. Serum nitric oxide (NO), tumour necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β) were also evaluated. RESULTS: The fingerprint chromatogram from HPLC indicated that AMP contained protocatechuic acid, chlorogenic acid, vanillic acid and caffeic acid. In the anti‐inflammatory test, AMP decreased paw oedema after Carr administration and increased the CAT, SOD and GPx activities and decreased the MDA level in paw oedema at 5 h after Carr injection. AMP also affected the serum NO, TNF‐α and IL‐1β levels at 5 h after Carr injection. Western blotting revealed that AMP decreased the expression of Carr‐induced inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2). CONCLUSION: Mesona procumbens has the potential to provide a therapeutic approach to inflammation‐associated disorders. Copyright © 2011 Society of Chemical Industry     

Differential response of four human livers to modulation of phase II enzyme systems by the chemopreventive phytochemical phenethyl isothiocyanate

A principal mechanism of the chemopreventive activity of isothiocyanates is detoxification of the genotoxic metabolites of chemical carcinogens through up‐regulation of enzymes such as quinone reductase and the glutathione‐S‐transferases. In this study we report, for the first time, the potential of the aromatic isothiocyanate, phenethyl isothiocyanate (PEITC) to modulate these enzymes in human liver from four donors, in comparison with rat liver. Precision‐cut human and rat liver slices were incubated with PEITC at concentrations that can be achieved in plasma following dietary intake. Glutathione‐S‐transferase activity increased in rat slices whereas in human slices activity rose only in three of the four donors. At the protein level, a marked rise in GSTα was seen in one of the human donors whereas much less pronounced elevation was noted in the other three. Quinone reductase activity doubled in rat liver slices incubated with PEITC, and was accompanied by an increase in protein expression. Only in one of the human donors was activity and expression of quinone reductase elevated. These studies illustrate that there are very pronounced differences in the response of human liver to PEITC, indicating that the chemopreventive effect of isothiocyanates may not be manifested in all individuals.     

Anti‐inflammatory Potential of Quercetin‐3‐O‐β‐D‐(“2”‐galloyl)‐glucopyranoside and Quercetin Isolated from Diospyros kaki calyx via Suppression of MAP Signaling Molecules in LPS‐induced RAW 264.7 Macrophages

Diospyros kaki (DK) contains an abundance of flavonoids and has been used in folk medicine in Korea for centuries. Here, we report for the first time the anti‐inflammatory activities of Quercetin (QCT) and Quercetin 3‐O‐β‐(“2”‐galloyl)‐glucopyranoside (Q32G) isolated from DK. We have determine the no cytotoxicity of Q32G and QCT against RAW 264.7 cells up to concentration of 50 μM. QCT and Q32G demonstrated potent anti‐inflammatory activities by reducing expression of nitric oxide (NO), tumor necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐6 inducible NO synthase (iNOS), cyclooxygenase (COX)‐2, and mitogen‐activated protein kinase (MAPKs) in mouse RAW 264.7 macrophages activated with lipopolysaccharide (LPS). Both QCT or Q32G could decrease cellular protein levels of COX‐2 and iNOS as well as secreted protein levels of NO, PGE₂, and cytokines (TNF‐α, IL‐1β, and IL‐6) in culture medium of LPS‐stimulated RAW 264.7 macrophages. Immunoblot analysis showed that QCT and Q32G suppressed LPS‐induced MAP kinase pathway proteins p‐p38, ERK, and JNK. This study revealed that QCT and Q32G have anti‐inflammatory potential, however Q32G possess comparable activity as that of QCT and could be use as adjuvant to treat inflammatory diseases.     

Systemic inflammatory load in humans is suppressed by consumption of two formulations of dried,encapsulated juice concentrate

Chronic inflammation contributes to an increased risk for developing chronic conditions such as cardiovascular disease, diabetes, and cancer. A high “inflammatory load” is defined as elevated inflammation markers in blood or other tissues. We evaluated several markers of systemic inflammation from healthy adults and tested the hypothesis that two formulations of encapsulated fruit and vegetable juice powder concentrate with added berry powders (FVB) or without (FV) could impact markers of inflammatory load. Using a double‐blind, placebo‐controlled approach, 117 subjects were randomly assigned to receive placebo, FV, or FVB capsules. Blood was drawn at baseline and after 60 d of capsule consumption. We measured inflammatory markers (high sensitivity C‐Reactive Protein, Monocyte Chemotactic Protein‐1, Macrophage Inflammatory Protein 1‐β, and Regulated upon Activation, Normal T cell Expressed and Secreted), superoxide dismutase, and micronutrients (β‐carotene, vitamin C, and vitamin E). Results showed Monocyte Chemotactic Protein‐1, Macrophage Inflammatory Protein 1‐β, and RANTES levels were significantly reduced and superoxide dismutase and micronutrient levels were significantly increased in subjects consuming both FV and FVB, relative to placebo. Data suggest a potential health benefit by consuming either formulation of the encapsulated juice concentrates through their anti‐inflammatory properties.