Resveratrol blocks interleukin-1beta-induced activation of the nuclear transcription factor NF-kappaB, inhibits proliferation, causes S-phase arrest, and induces apoptosis of acute myeloid leukemia cells

50-Hz extremely low frequency electromagnetic fields enhance cell proliferation and DNA damage: possible involvement of a redox mechanism

HL-60 leukemia cells, Rat-1 fibroblasts and WI-38 diploid fibroblasts were exposed for 24-72 h to 0.5-1.0-mT 50-Hz extremely low frequency electromagnetic field (ELF-EMF). This treatment induced a dose-dependent increase in the proliferation rate of all cell types, namely about 30% increase of cell proliferation after 72-h exposure to 1.0 mT. This was accompanied by increased percentage of cells in the S-phase after 12- and 48-h exposure. The ability of ELF-EMF to induce DNA damage was also investigated by measuring DNA strand breaks. A dose-dependent increase in DNA damage was observed in all cell lines, with two peaks occurring at 24 and 72 h. A similar pattern of DNA damage was observed by measuring formation of 8-OHdG adducts. The effects of ELF-EMF on cell proliferation and DNA damage were prevented by pretreatment of cells with an antioxidant like alpha-tocopherol, suggesting that redox reactions were involved. Accordingly, Rat-1 fibroblasts that had been exposed to ELF-EMF for 3 or 24 h exhibited a significant increase in dichlorofluorescein-detectable reactive oxygen species, which was blunted by alpha-tocopherol pretreatment. Cells exposed to ELF-EMF and examined as early as 6 h after treatment initiation also exhibited modifications of NF kappa B-related proteins (p65-p50 and I kappa B alpha), which were suggestive of increased formation of p65-p50 or p65-p65 active forms, a process usually attributed to redox reactions. These results suggest that ELF-EMF influence proliferation and DNA damage in both normal and tumor cells through the action of free radical species. This information may be of value for appraising the pathophysiologic consequences of an exposure to ELF-EMF.

Effect of resveratrol and beta-sitosterol in combination on reactive oxygen species and prostaglandin release by PC-3 cells

The objective of this project was to identify some possible mechanisms by which two common phytochemicals, resveratrol and beta-sitosterol, inhibit the growth of human prostate cancer PC-3 cells. These mechanisms include the effect of the phytochemicals on apoptosis, cell cycle progression, prostaglandin synthesis and the production of reactive oxygen species (ROS). Prostaglandins have been known to play a role in regulating cell growth and apoptosis. PC-3 cells were supplemented with 50 microM resveratrol or 16 microM beta-sitosterol alone or in combination for up to 5 days. Phytochemical supplementation resulted in inhibition in cell growth. beta-Sitosterol was more potent than resveratrol and the combination of the two resulted in greater inhibition than supplementation with either alone. Long-term supplementation with resveratrol or beta-sitosterol elevated basal prostaglandin release but beta-sitosterol was much more potent than resveratrol in this regard. beta-Sitosterol was more effective than resveratrol in inducing apoptosis and the combination had an intermediate effect after 1 day of supplementation. Cells supplemented with resveratrol were arrested at the G1 phase and at the G2/M phase in the case of beta-sitosterol while the combination resulted in cell arrest at the two phases of the cell cycle. beta-Sitosterol increased ROS production while resveratrol decreased ROS production. The combination of the two phytochemicals resulted in an intermediate level of ROS. The observed changes in prostaglandin levels and ROS production by these two phytochemicals may suggest their mediation in the growth inhibition. The reduction in ROS level and increase by resveratrol supplementation in PC-3 cells reflects the antioxidant properties of resveratrol. It was concluded that these phytochemicals may induce the inhibition of tumor growth by stimulating apoptosis and arresting cells at different locations in the cell cycle and the mechanism may involve alterations in ROS and prostaglandin production.

Resveratrol, an extract of red wine, inhibits lipopolysaccharide induced airway neutrophilia and inflammatory mediators through an NF-kappaB-independent mechanism

Consumption of a naturally occurring polyphenol, resveratrol, in particular through drinking moderate amounts of red wine, has been suggested to be beneficial to health. A plethora of in vitro studies published demonstrate various anti-inflammatory actions of resveratrol. The aim of this research was to determine whether any of these anti-inflammatory effects translate in vivo in a rodent model of LPS induced airway inflammation. Resveratrol reduced lung tissue neutrophilia to a similar magnitude as that achieved by treatment with budesonide. This was associated with a reduction in pro-inflammatory cytokines and prostanoid levels. Interestingly, the reduction did not appear to be due to an impact on NF-kappaB activation or the expression of the respective genes as suggested by various in vitro publications. These results suggest that resveratrol may possess anti-inflammatory properties via a novel mechanism. Elucidation of this mechanism may lead to potential new therapies for the treatment of chronic inflammation.

Ellagic acid and quercetin interact synergistically with resveratrol in the induction of apoptosis and cause transient cell cycle arrest in human leukemia cells

Anticarcinogenic effects of polyphenolic compounds in fruits and vegetables are well established. Although polyphenols naturally occur as combinations, little information is available regarding possible synergistic or antagonistic biochemical interactions between compounds. Identifying potential interactions between polyphenols may provide information regarding the efficiency of polyphenol-containing foods in cancer prevention. The objective of this study was to investigate the interactions of ellagic acid and quercetin with resveratrol, polyphenols which occur in muscadine grapes, with the hypothesis that the selected polyphenols would interact synergistically in the induction of apoptosis and reduction of cell growth in human leukemia cells (MOLT-4). To test this hypothesis, alterations in cell cycle kinetics, proliferation, and apoptosis (caspase-3 activity) were examined after incubation with ellagic acid, quercetin, and resveratrol as single compounds and in combination. Results showed a more than additive interaction for the combination of ellagic acid with resveratrol and furthermore, significant alterations in cell cycle kinetics induced by single compounds and combinations were observed. An isobolographic analysis was performed to assess the apparent synergistic interaction for the combinations of ellagic acid with resveratrol and quercetin with resveratrol in the induction of caspase 3 activity, confirming a synergistic interaction with a combination index of 0.64 for the combination of ellagic acid and resveratrol and 0.68 for quercetin and resveratrol. Results indicate that the anticarcinogenic potential of foods containing polyphenols may not be based on the effects of individual compounds, but may involve a synergistic enhancement of the anticancer effects.

Inhibition of IκB Kinase Activity by Acetyl-boswellic Acids Promotes Apoptosis in Androgen-independent PC-3 Prostate Cancer Cells in Vitro and in Vivo

Signaling through NF-kappaB has been implicated in the malignant phenotype as well as the chemoresistance of various cancers. Here we show that the natural compounds acetyl-beta-boswellic acid and acetyl-11-keto-beta-boswellic acid (AKbetaBA) inhibit proliferation and elicit cell death in chemoresistant androgen-independent PC-3 prostate cancer cells in vitro and in vivo. Induction of apoptosis was demonstrated in cultured PC-3 cells by several parameters including mitochondrial cytochrome c release and DNA fragmentation. At the molecular level these compounds inhibit constitutively activated NF-kappaB signaling by intercepting the IkappaB kinase (IKK) activity; signaling through the interferon-stimulated response element remained unaffected, suggesting specificity for IKK inhibition. The impaired phosphorylation of p65 and the reduced nuclear translocation of NF-kappaB proteins were associated with down-regulation of the constitutively overexpressed and NF-kappaB-dependent antiapoptotic proteins Bcl-2 and Bcl-x(L). In addition, expression of cyclin D1, a crucial cell cycle regulator, was reduced as well. Down-regulation of IKK by antisense oligodeoxynucleotides confirmed the essential role of IKK inhibition for the proliferation of the PC-3 cells. Both compounds tested were active in vivo, yet AKbetaBA proved to be far superior. Indeed, topical application of water-soluble AKbetaBA-gamma-cyclodextrin on PC-3 tumors xenografted onto chick chorioallantoic membranes induced concentration-dependent inhibition of proliferation as well as apoptosis. Similarly, in nude mice carrying PC-3 tumors, systemic application of AKbetaBA-gamma-cyclodextrin inhibited tumor growth and triggered apoptosis in the absence of detectable systemic toxicity. Thus, AKbetaBA and related compounds acting on IKK might provide a novel approach for the treatment of chemoresistant human tumors such as androgen-independent human prostate cancers.

Acetyl-boswellic acids inhibit lipopolysaccharide-mediated TNF-alpha induction in monocytes by direct interaction with IkappaB kinases

Expression of proinflammatory cytokines by monocytes is tightly regulated by transcription factors such as NF-kappaB. In this study, we show that, in LPS-stimulated human peripheral monocytes, the pentacyclic triterpenes acetyl-alpha-boswellic acid (AalphaBA) and acetyl-11-keto-beta-boswellic acid (AKbetaBA) down-regulate the TNF-alpha expression. AalphaBA and AKbetaBA inhibited NF-kappaB signaling both in LPS-stimulated monocytes as detected by EMSA, as well as in a NF-kappaB-dependent luciferase gene reporter assay. By contrast, the luciferase expression driven by the IFN-stimulated response element was unaffected, implying specificity of the inhibitory effect observed. Both AalphaBA and AKbetaBA did not affect binding of recombinant p50/p65 and p50/c-Rel dimers to DNA binding sites as analyzed by surface plasmon resonance. Instead, both pentacyclic triterpenes inhibited the LPS-induced degradation of IkappaBalpha, as well as phosphorylation of p65 at Ser(536) and its nuclear translocation. AalphaBA and AKbetaBA inhibited specifically the phosphorylation of recombinant IkappaBalpha and p65 by IkappaBalpha kinases (IKKs) immunoprecipitated from LPS-stimulated monocytes. In line with this, AalphaBA and AKbetaBA also bound to and inhibited the activities of active human recombinant GST-IKKalpha and His-IKKbeta. The LPS-triggered induction of TNF-alpha in monocytes is dependent on IKK activity, as confirmed by IKK-specific antisense oligodeoxynucleotides. Thus, via their direct inhibitory effects on IKK, AalphaBA and AKbetaBA convey inhibition of NF-kappaB and subsequent down-regulation of TNF-alpha expression in activated human monocytes. These findings provide a molecular basis for the anti-inflammatory properties ascribed to AalphaBA- and AKbetaBA-containing drugs and suggest acetyl-boswellic acids as tools for the development of novel therapeutic interventions.

Oxidative stress and nutritional prevention in autoimmune rheumatic diseases

The hypothesis that oxidative stress favours flogistic and immune processes inducing autoimmune rheumatic diseases (ARDs) and their complications is still under discussion. In this review we take into consideration both the aetiopathological role of the diet in such diseases and the possible efficacy of dietary supports as adjuvants for the usual specific therapies. Moreover, we shall examine the hypothetical pathophysiological role of oxidative stress on ARDs and their complications, the methods for its evaluation and the possibility of intervening on oxidative pathways by means of nutritional modulation. It is possible that in the future we will be able to control connective pathology by associating an immuno-modulating therapy ('re-educating') with natural products having an anti-oxidant activity to current immunosuppressive treatment (which has potentially toxic effects).

Effect of resveratrol on the development of spontaneous mammary tumors in HER-2/neu transgenic mice

Resveratrol (Res) has been reported to possess cancer chemopreventive activity on the basis of its in vitro effects on tumor cells and in vivo experimental models of rodents transplanted with parental tumors or treated with carcinogens. We investigated the effects of Res on the development of mammary tumors appearing spontaneously in HER-2/neu transgenic mice at an early age. The mechanisms involved in the Res antitumor effect were evaluated by studying the immune effectiveness, tumor apoptosis and expression of mRNA and protein for HER-2/neu in tumoral mammary glands from Res-treated mice and in tumor cell lines. Res supplementation delayed the development of spontaneous mammary tumors (p < 0.001), reduced the mean number and size of mammary tumors (p < 0.0001) and diminished the number of lung metastases in HER-2/neu transgenic mice. The effects of Res were associated with downregulation of HER-2/neu gene expression and increased apoptosis both in tumoral mammary glands and in murine (N202) and human (SKBr3) tumor cell lines. Neither the basal, the IL-2-induced NK activity nor the lymphocyte number and proliferation was modified in Res-supplemented compared to control mice. Our results demonstrate that Res supplementation delays the development and reduces the metastasizing capacity of spontaneous mammary tumors in HER-2/neu transgenic mice. The antitumor effect of Res might be related to the downregulation of HER-2/neu expression and the induction of apoptosis in tumor cells.

Resveratrol interference with the cell cycle protects human neuroblastoma SH-SY5Y cell from paclitaxel-induced apoptosis

In previous studies we demonstrated that resveratrol acts in an antiapoptotic manner on the paclitaxel-treated human neuroblastoma (HN) SH-SY5Y cell line inhibiting the apoptotic pathways induced by the antineoplastic drug. In the present study we evaluated the antiapoptotic effect of resveratrol, studying its activity on cell cycle progression. We determined the mitotic index of cultures exposed to resveratrol and paclitaxel alone or in combination, the cell cycle distribution by flow cytometric analysis (FACS), and the modulation of some relevant cell cycle regulatory proteins. Resveratrol is able to induce S-phase cell arrest and this interference with the cell cycle is associated with an increase of cyclin E and cyclin A, a downregulation of cyclin D1, and no alteration in cyclin B1 and cdk 1 activation. The resveratrol-induced S-phase block prevents SH-SY5Y from entering into mitosis, the phase of the cell cycle in which paclitaxel exerts its activity, explaining the antiapoptotic effect of resveratrol.

Role of chemopreventive agents in cancer therapy

Tumorigenesis or carcinogenesis is a multi-step process that is induced primarily by carcinogens leading to the development of cancer. Extensive research in the last few years has revealed that regular consumption of certain fruits and vegetables can reduce the risk of acquiring specific cancers. Phytochemicals derived from such fruits and vegetables, referred to as chemopreventive agents include genistein, resveratrol, diallyl sulfide, S-allyl cysteine, allicin, lycopene, capsaicin, curcumin, 6-gingerol, ellagic acid, ursolic acid, silymarin, anethol, catechins and eugenol. Because these agents have been shown to suppress cancer cell proliferation, inhibit growth factor signaling pathways, induce apoptosis, inhibit NF-kappaB, AP-1 and JAK-STAT activation pathways, inhibit angiogenesis, suppress the expression of anti-apoptotic proteins, inhibit cyclooxygenase-2, they may have untapped therapeutic value. These chemopreventive agents also have very recently been found to reverse chemoresistance and radioresistance in patients undergoing cancer treatment. Thus, these chemopreventive agents have potential to be used as adjuncts to current cancer therapies.

Molecular basis of chemoprevention by resveratrol: NF-kappaB and AP-1 as potential targets

Recently, chemoprevention by the use of naturally occurring substances is considered as a priority to reduce the ever-increasing incidence of cancer. The intervention of multistage carcinogenesis by modulating intracellular signaling pathways may provide molecular basis of chemoprevention with a wide variety of dietary phytochemicals. Resveratrol, a red wine polyphenol, has been studied extensively for the chemopreventive activity in the context of its ability to interfere with the multistage carcinogenesis. Numerous intracellular signaling cascades converge with the activation of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1), which act independently or coordinately to regulate expression of target genes. These ubiquitous eukaryotic transcription factors mediate pleiotropic effects on cellular transformation and tumor promotion. This review aims to update the molecular mechanisms underlying chemoprevention by resveratrol with special focus on its effect on cellular signaling cascades mediated by NF-kappaB and AP-1.

Interleukin-1beta maintains an apoptosis-resistant phenotype in the blast cells of acute myeloid leukaemia via multiple pathways

Blast cell survival in suspension culture is associated with chemoresistance in acute myeloid leukaemia (AML). Autonomous production of IL-1beta by AML blasts is linked with a proliferative response, although its role in survival and hence apoptosis-resistance has not been examined in this disease. Cells that secreted more than 19.7 pg/ml IL-1beta were significantly more resistant to spontaneous apoptosis in 48-h culture than those that produced less than 19.7 pg/ml IL-1beta (P=0.008). Exogenous rhIL-1beta significantly enhanced 48-h survival in 25/29 blast cell samples (P=0.0001). IL-1 receptor ligation is known to activate at least three survival pathways: those mediated by PI-3 kinase, IL-1 receptor-associated kinase (IRAK) and ceramidase. In apoptosis-sensitive AML blasts with a strong survival response to rhIL-1beta, inhibitors of all three pathways down-modulated an IL-1beta-mediated increase in blast survival, but only the inhibition of all three pathways totally eliminated viable blasts. In apoptosis-resistant and apoptosis-sensitive primary AML samples, the three inhibitors all increased apoptosis in vitro after 48 h. Exogenous rhIL-1beta induced the hyperphosphorylation of Bcl-2. It also increased the activation of NF-kappaB in 5/15 blast samples. IL-1beta-mediated survival pathways may be a factor in apoptosis-resistance in primary AML blasts, and may therefore contribute to chemoresistance.

Flavonoids Induce Apoptosis in Human Leukemia U937 Cells Through Caspase- and Caspase-Calpain-Dependent Pathways

Flavonoids are polyphenolic phytochemicals that are ubiquitous in plants and present in the common human diet. They may exert diverse beneficial effects, including antioxidant and anticarcinogenic activities. In this study we tested the apoptotic activity of 22 flavonoids and related compounds in leukemic U937 cells. Several flavones but none of the isoflavones or flavanones tested induced apoptotic cell death under these conditions, as determined by reduction in cell viability, flow cytometry, and oligonucleosomal DNA fragmentation. Structure-activity relationship showed that at least two hydroxylations in positions 3, 5, and 7 of the A ring were needed to induce apoptosis, whereas hydroxylation in 3' and/or 4' of the B ring enhanced proapoptotic activity. At lower concentrations, these compounds were also able to sensitize these cells to apoptosis induced by tumor necrosis factor-alpha. Regarding the mechanisms, galangin, luteolin, chrysin, and quercetin induced apoptosis in a way that required the activation of caspases 3 and 8, but not caspase 9. In contrast, an active role of calpains in addition to caspases was demonstrated in apoptosis induced by fisetin, apigenin, and 3,7-dihydroxyflavone. Our data show evidence of the proapoptotic properties of some flavonoids that could support their rational use as chemopreventive and therapeutic agents against carcinogenic disease.

Activation loop phosphorylation controls protein kinase D-dependent activation of nuclear factor kappaB

Activation of the inducible transcription factor nuclear factor kappaB (NF-kappaB) occurs in cells exposed to oxidative stress, and the serine/threonine kinase protein kinase D (PKD) is critical for signal relay to NF-kappaB. We have recently delineated two coordinated events that control PKD activation in response to oxidative stress: phosphorylation at Tyr463 by the tyrosine kinase Abl, and phosphorylation at the activation loop Ser738/Ser742 by the protein kinase C (PKC) isoform PKCdelta. The result is fully active PKD that controls NF-kappaB activation through the IkappaB kinase (IKK) complex. Here, we investigate the mechanism by which PKD controls IKK/NF-kappaB activation. Resveratrol, a potent antioxidant, blocks both PKD activation and NF-kappaB induction. In particular, resveratrol blocked PKD activation loop phosphorylation and activity, and this was caused by a specific inhibition of the Ser738/Ser742 kinase PKCdelta. On the other hand, resveratrol did not affect Abl kinase activity and had no effect on Tyr463 phosphorylation. Moreover, we show that the mechanism by which resveratrol inhibits NF-kappaB is by blocking the translocation of PKD to the IKK complex, specifically by inhibiting Ser738/Ser742 phosphorylation. We therefore propose that rather than acting as an antioxidant, resveratrol specifically blocks oxidative stress-dependent NF-kappaB activation by interfering with PKD phosphorylation and association with the IKK complex.

Differential regulation of resveratrol on lipopolysacchride-stimulated human macrophages with or without IFN-γ pre-priming

Resveratrol, a polyphenol compound found in grapes and red wines, is a prominent anti-cancer agent. In this study, we demonstrate that resveratrol enhanced TNF-alpha, IL-12 and IL-1beta production from LPS activated phorbol myristate acetate (PMA) differentiated THP-1 human macrophages. Expression of CD86 on macrophages was enhanced by resveratrol alone and with LPS. When macrophages were primed with IFN-gamma, resveratrol suppressed the expression of HLA-ABC, HLA-DR, CD80, CD86 and inhibited production of TNF-alpha, IL-12, IL-6 and IL-1beta induced by LPS. The differential impact of resveratrol on expression of CD14 might be correlated with differential response of macrophages to LPS with or without IFN-gamma priming.

The in vitro effects of H-89, a specific inhibitor of protein kinase A, in the human colonic carcinoma cell line Caco-2

SUMMARY

H-89 is a compound characterized in vitro as a potent and selective inhibitor of protein kinase A. In the present study, we observed that H-89 induced morphological transformation and caused growth inhibition of the human colon cancer cell line Caco-2 in a dose-dependent manner. However, another protein kinase A inhibitor, H-8, had no effect on Caco-2 cells. To evaluate the possible molecular mechanism of H-89-evoked effects in Caco-2 cells, we analysed the capacity of H-89 to regulate the protein kinase B (Akt/PKB) signalling pathway. H-89 treatment led to an activation of Akt/PKB in Caco-2 cells. This activation was phosphatidylinositol 3 (PI3)-kinase-dependent and promoted survival of Caco-2 cells because the PI3 kinase inhibitor LY294002 inhibited the Akt/PKB activation and induced apoptosis of Caco-2 cells. To test whether Akt/PKB activity promoted resistance to H-89-induced effects, LY294002 was added in combination with H-89. LY294002 greatly potentiated the H-89-induced growth inhibition and apoptosis of Caco-2 cells. These results suggest that the H-89-induced growth inhibition of Caco-2 cells is associated with phosphorylation of Akt/PKB protein and that the cells become more sensitive to H-89 and die by apoptosis upon inhibition of the PI3K/Akt pathway.

Resveratrol, a polyphenol found in grapes, suppresses oxidative damage and stimulates apoptosis during early colonic inflammation in rats

Oxidative stress, neutrophil infiltration, proinflammatory cytokines and eicosanoid generation are clearly involved in the pathogenesis of intestinal bowel disease. Resveratrol, a polyphenolic compound found in grapes and wine, has been shown to have anti-inflammatory, antioxidant, antitumour and immunomodulatory activities, however, its effects on experimental colitis remain unknown. We have investigated the effects of resveratrol on the colon injury caused by intracolonic instillation of trinitrobenzenesulphonic acid (TNBS) in rats. We determined the production of prostaglandin (PG)E(2) and PGD(2) in colon mucosa and the expression of cyclo-oxygenases (COX)-1 and -2 immunohistochemically. The inflammatory response was assessed by histology and myeloperoxidase activity, as an index of neutrophil infiltration. Interleukin-1 beta production, histological and histochemical analysis of the lesions were also carried out. Finally, since resveratrol has been found to modulate apoptosis we intended to elucidate its effects on colonic mucosa under early acute inflammatory conditions. Resveratrol (5-10mg/kg/day) significantly reduced the degree of colonic injury, the index of neutrophil infiltration and the levels of the cytokine. Resveratrol did not revert the increased PGE(2) levels but produced a significant fall in the PGD(2) concentration. Compared with inflamed colon, no changes in staining for COX-1 were observed in colon of resveratrol and TNBS-treated rats. In contrast, COX-2 expression was decreased. Furthermore, resveratrol enhanced apoptosis compared with already high level induced by TNBS. In conclusion, resveratrol reduces the damage in experimentally induced colitis, alleviates the oxidative events and stimulates apoptosis.

Herbal bioactivation: the good, the bad and the ugly

It has been well established that the formation of reactive metabolites of drugs is associated with drug toxicity. Similarly, there are accumulating data suggesting the role of the formation of reactive metabolites/intermediates through bioactivation in herbal toxicity and carcinogenicity. It has been hypothesized that the resultant reactive metabolites following herbal bioactivation covalently bind to cellular proteins and DNA, leading to toxicity via multiple mechanisms such as direct cytotoxicity, oncogene activation, and hypersensitivity reactions. This is exemplified by aristolochic acids present in Aristolochia spp, undergoing reduction of the nitro group by hepatic cytochrome P450 (CYP1A1/2) or peroxidases in extrahepatic tissues to reactive cyclic nitrenium ion. The latter was capable of reacting with DNA and proteins, resulting in activation of H-ras oncogene, gene mutation and finally carcinogenesis. Other examples are pulegone present in essential oils from many mint species; and teucrin A, a diterpenoid found in germander (Teuchrium chamaedrys) used as an adjuvant to slimming diets. Extensive pulegone metabolism generated p-cresol that was a glutathione depletory, and the furan ring of the diterpenoids in germander was oxidized by CYP3A4 to reactive epoxide which reacts with proteins such as CYP3A and epoxide hydrolase. On the other hand, some herbal/dietary constituents were shown to form reactive intermediates capable of irreversibly inhibiting various CYPs. The resultant metabolites lead to CYP inactivation by chemical modification of the heme, the apoprotein, or both as a result of covalent binding of modified heme to the apoprotein. Some examples include bergamottin, a furanocoumarin of grapefruit juice; capsaicin from chili peppers; glabridin, an isoflavan from licorice root; isothiocyanates found in all cruciferous vegetables; oleuropein rich in olive oil; dially sulfone found in garlic; and resveratrol, a constituent of red wine. CYPs have been known to metabolize more than 95% therapeutic drugs and activate a number of procarcinogens as well. Therefore, mechanism-based inhibition of CYPs may provide an explanation for some reported herb-drug interactions and chemopreventive activity of herbs. Due to the wide use and easy availability of herbal medicines, there is increasing concern about herbal toxicity. The safety and quality of herbal medicine should be ensured through greater research, pharmacovigilance, greater regulatory control and better communication between patients and health professionals.

[A rare cause of neonatal exudative enteropathy: congenital Langerhans cell histiocytosis (histiocytosis X)]

A case of Langerhans cell histiocytosis is reported in a neonate. Intestinal involvement was especially diffuse and severe, presenting as a protein-losing enteropathy secondary to massive mucosal infiltration by histiocytic cells. The infant died at the age of 3 1/2 months despite therapy with corticosteroids and vinblastine then etoposide and interferon. Such an outcome confirmed the severity of forms with neonatal onset and digestive involvement.