A Pharmacological Update of Ellagic Acid.

Ellagic acid is a common metabolite present in many medicinal plants and vegetables. It is present either in free form or as part of more complex molecules (ellagitannins), which can be metabolized to liberate ellagic acid and several of its metabolites, including urolithins. While ellagic acid's antioxidant properties are doubtless responsible for many of its pharmacological activities, other mechanisms have also been implicated in its various effects, including its ability to reduce the lipidemic profile and lipid metabolism, alter pro-inflammatory mediators (tumor necrosis factor-α, interleukin-1ß, interleukin-6), and decrease the activity of nuclear factor-κB while increasing nuclear factor erythroid 2-related factor 2 expression. These events play an important role in ellagic acid's anti-atherogenic, anti-inflammatory, and neuroprotective effects. Several of these activities, together with the effect of ellagic acid on insulin, glycogen, phosphatases, aldose reductase, sorbitol accumulation, advanced glycation end-product formation, and resistin secretion, may explain its effects on metabolic syndrome and diabetes. In addition, results from recent research have increased the interest in ellagic acid, both as a potential protective agent of the liver and skin and as a potential anticancer agent, due to the specific mechanisms affecting cell proliferation, apoptosis, DNA damage, and angiogenesis and its aforementioned anti-inflammatory properties. Taken together, these effects make ellagic acid a highly interesting compound that may contribute to different aspects of health; however, more studies are needed, especially on the compound's pharmacokinetic profile. In this review, we selected papers published from 2005 to the present.

Phenolic substances from Phagnalon rupestre protect against 2,4,6-trinitrochlorobenzene-induced contact hypersensitivity.

2-isoprenylhydroquinone-1-glucoside (1), 3,5-dicaffeoylquinic acid (2), and 3,5-dicaffeoylquinic acid methyl ester (3), isolated from Phagnalon rupestre, improved the contact hypersensitivity response to 2,4,6-trinitrochlorobenzene in mice. These phenolics reduced ear swelling and IL-1ß content by 50% 24 h after challenge; in addition, 2 inhibited tumor necrosis factor-α by 53%. All three compounds also reduced interleukin-2 content by 50% 72 h after challenge. Both 2 and 3 inhibited metalloproteinase-9 levels in the skin lesions by 66% and 41%, respectively, and lowered cyclooxygenase-2 expression by 44% and 49%, respectively, at 24 h. Moreover, 2 was effective against atopic dermatitis induced by repeated application of 2,4,6-trinitrochlorobenzene; it attenuated edema by over 40% from day 7 and inhibited inflammatory cell infiltration by 44% at day 22. In addition, 1-3 reduced metalloproteinase-9 expression in a dose-dependent manner in macrophages RAW 264.7 stimulated with lipopolysaccharide. Thus, compounds 2 and 3 were found to exhibit a greater activity against contact hypersensitivity than 1.

Interaction of dicaffeoylquinic derivatives with peroxynitrite and other reactive nitrogen species.

Plant phenolic antioxidants, among them catechins and hydroxycinnamoyl conjugates, constitute a well defined class of inhibitors of reactive nitrogen species (RNS). To gain deeper insight in this field, we examined the effects of 3,5-di-O-caffeoylquinic acid (DCA), its methyl ester (DCE) and epigallocatechin gallate (EGCG) in nitrative and oxidative processes. These compounds were found to be strong inhibitors of the nitration of tyrosine residues induced by ONOO- in bovine seroalbumin, with their IC50 values (10-40 microM) notably decreasing in the presence of bicarbonate. When studied on the intracellular protein tyrosine nitration induced by ONOO- in cultured murine fibroblasts as well as that induced by phorbol ester (PMA) in nitrite-supplemented human neutrophils, all three phenolics were also effective (100% and over 75% inhibition for fibroblasts and neutrophils, respectively, at 25 microM). This ability seems to be due to a direct interaction with ONOO- or with the species generated by leukocytes. The possible interference with the production of NO was also studied: both DCA and EGCG inhibited nitrite production in LPS-stimulated macrophages by 24% and 40%, respectively, and the expression of nitric oxide synthase-2 (NOS-2), as well. DCA and EGCG reduced by 52% and 59%, respectively, the NF-kappaB transcriptional activity. In contrast, DCE did not show any effect. The assayed phenolics exert varying degrees of protection against the chemical modifications induced by RNS depending not only on the hydroxyl pattern, but also on the presence of bicarbonate.

New insight into the inhibition of the inflammatory response to experimental delayed-type hypersensitivity reactions in mice by scropolioside A.

Scropolioside A, an iridoid isolated from Scrophularia auriculata ssp. pseudoauriculata, showed anti-inflammatory properties against different experimental models of delayed-type hypersensitivity. This iridoid reduced the oedema induced by oxazolone by 79% (72 h) at 0.5 mg/ear while reducing that induced by sheep red blood cells by 47% (18 h), 45% (24 h) and 36% (48 h) at 10 mg/kg. In vivo it reduced both oedema formation and cell infiltration whereas in vitro it reduced the proliferation of activated T-lymphocytes (IC50 of 67.74 microM). Treatment with scropolioside A (100 microM) 18 and 24 h after phytohemagglutinin stimulation increased the number of cells arrested in the subG(0) phase whereas treatment 3 h after stimulation clearly increased the number of cells that passed to the S phase. Scropolioside A also inhibited the production of prostaglandin E2, leukotriene B4, nitric oxide, interleukin-1beta, interleukin-2, interleukin-4, tumour necrosis factor-alpha and interferon-gamma, but had no effect on the production of interleukin-10. Moreover, it modified the expression of both nitric oxide synthase-2 and cyclooxygenase-2, as well as the activation of nuclear factor-kappaB in RAW 264.7 macrophages.

Effects of naturally occurring dihydroflavonols from Inula viscosa on inflammation and enzymes involved in the arachidonic acid metabolism.

The anti-inflammatory properties of three flavanones isolated from Inula viscosa, sakuranetin, 7-O-methylaromadendrin, and 3-acetyl-7-O-methylaromadendrin, have been tested both in vitro and in vivo. Acute inflammation in vivo was induced by means of topical application of 12-O-tetradecanoylphorbol 13-acetate (TPA) to mouse ears or by subcutaneous injection of phospholipase A(2) (PLA(2)) into mouse paws. The test compounds were evaluated in vitro for their effect on both the metabolism of arachidonic acid and on the release and/or activity of enzymes involved in the inflammatory response such as elastase, myeloperoxidase (MPO), and protein kinase C (PKC). The most active compounds in vivo against PLA(2)-induced paw oedema were 7-O-methylaromadendrin (ED(50)=8 mg/kg) and sakuranetin (ED(50)=18 mg/kg). In contrast, the most potent compound against TPA-induced ear oedema was 3-acetyl-7-O-methylaromadendrin (ED(50)=185 microg/ear), followed by sakuranetin (ED(50)=205 microg/ear). In vitro, the latter compound was the most potent inhibitor of leukotriene (LT) B(4) production by peritoneal rat neutrophils (IC(50)=9 microM) and it was also the only compound that directly inhibited the activity of 5-lipoxygenase (5-LOX). 3-Acetyl-7-O-methylaromadendrin also inhibited LTB(4) production (IC(50)=15 microM), but had no effect on 5-LOX activity. The only flavanone that inhibited the secretory PLA(2) activity in vitro was 7-O-methylaromadendrin. This finding may partly explain the anti-inflammatory effect observed in vivo, although other mechanisms such as the inhibition of histamine release by mast cells may also be implicated. Sakuranetin at 100 microM was found to inhibit elastase release, although this result is partly due to direct inhibition of the enzyme itself. At the same concentration, 7-O-methylaromadendrin only affected the enzyme release. Finally, none of the flavanones exhibited any effect on MPO or PKC activities. Taken together, these findings indicate that sakuranetin may be a selective inhibitor of 5-LOX.

Inhibition of the pro-inflammatory mediators' production and anti-inflammatory effect of the iridoid scrovalentinoside.

We have studied scrovalentinoside, an iridoid with anti-inflammatory properties isolated from Scrophularia auriculata ssp. pseudoauriculata, as an anti-inflammatory agent in different experimental models of delayed-type hypersensitivity. We found that scrovalentinoside reduced the edema induced by oxazolone at 0.5 mg/ear and sheep red blood cells at 10 mg/kg. The observed effect occurred during the last phase or inflammatory response; during the earlier phase or induction of the delayed-type hypersensitivity reaction, no significant activity was noted. Thus, scrovalentinoside reduced both the edema and cell infiltration in vivo and reduced lymphocyte proliferation in vitro, affecting the cycle principally during the first 48 h. Whereas cells stimulated with phytohemagglutinin changed from the G(0)/G(1) phase to the S and G(2)/M phases, when these same cells were treated with scrovalentinoside (100 microM), they remained in the G(0)/G(1) phase. Finally, scrovalentinoside inhibited the production of the pro-inflammatory mediators' TNF-alpha, IFN-gamma, IL-1beta, IL-2, IL-4, LTB(4), and NO, but had no effect on the production of the anti-inflammatory cytokine IL-10.

Chemopreventive effect of oleuropein in colitis-associated colorectal cancer in c57bl/6 mice.

SCOPE: The main phenolic secoiridoid oleuropein and active constituent from olive tree (Olea europaea, Oleaceae), has demonstrated anti-inflammatory properties in intestinal inflammation and anti-tumoral effects in different cancer cells. In this study, we evaluated the chemoprevention of oleuropein in a model of azoxymethane (AOM)/Dextran sulfate sodium (DSS)-induced colorectal cancer (CRC) in C57BL/6 mice and the modulatory effect on the Th17 response in DSS acute colitis. METHODS AND RESULTS: Oleuropein protected from AOM/DSS-induced CRC by improving clinical symptoms, disease activity index score as well as suppressed the growth and multiplicity of colonic tumors. Treatment with oleuropein reduced intestinal IL-6, IFN-γ, TNF-α, and IL-17A concentration, and decreased cyclooxygenase-2, Bax and proliferating cell nuclear antigen protein expression. Western blot analysis also showed a markedly downregulation of CRC-related pathways as nuclear factor-κB (NF-κB), Wnt/ß-catenin, phosphatidylinositol-3-kinase (P3IK)/Akt, and signal transducer and activators of transcription (STAT)3. In DSS acute model, oleuropein inhibited Th17 response, by decreasing CD4(+) Rorγt(+) IL-17(+) IFN-γ(+) T-cell subsets in the lamina propria, as well as IL-17A and IFN-γ expression. CONCLUSION: Oleuropein as a dietary supplementation could be a promising protective agent against colitis-associated CRC.

A new dual inhibitor of arachidonate metabolism isolated from Helichrysum italicum.

Six acetophenones (1-6) and one gamma-pyrone (7), previously isolated from Helichrysum italicum, were tested for their ability to inhibit enzymatic and non-enzymatic lipid peroxidation, the stable 1,1-diphenyl-2-pycryl-hydrazyl free radical, superoxide scavenging and arachidonic acid metabolism. In addition, they were studied in different experimental models such as the chronic inflammation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA), the phospholipase A(2)-induced mouse paw oedema test, the carrageenan-induced mouse paw oedema test, and the writhing induced by acetic acid in the mouse. Of the assayed compounds, only 1 inhibited enzymatic lipid peroxidation but had no effect on non-enzymatic lipid peroxidation. None of them scavenged the superoxide radical. Study of the inhibition of arachidonic acid metabolism demonstrated that 1 was an inhibitor of both cyclooxygenase and 5-lipoxygenase, whereas 2 was a selective inhibitor of 5-lipoxygenase. In the assay of phospholipase A(2)-induced mouse paw oedema, the gamma-pyrone derivative inhibited oedema formation, showing a similar profile to that obtained with cyproheptadine. The acetophenones were effective at 30 and 60 min. In the carrageenan test, acetophenone 1 gave the best results and had analgesic effects in the acetic acid writhing test. In conclusion acetophenone 1 (4-hydroxy-3-(3-methyl-2-butenyl)acetophenone) is a new dual inhibitor of arachidonate metabolism, and could be a useful tool for obtaining anti-inflammatory and analgesic drugs.

Assessment of the anti-inflammatory activity and free radical scavenger activity of tiliroside.

Three flavonoids, gnaphaliin, pinocembrin and tiliroside, isolated from Helichrysum italicum, were studied in vitro for their antioxidant and/or scavenger properties and in vivo in different models of inflammation. In vitro tests included lipid peroxidation in rat liver microsomes, superoxide radical generation in the xanthine/xanthine oxidase system and the reduction of the stable radical 1,1-diphenyl-2-pycryl-hydrazyl (DPPH). Acute inflammation was induced by application of 12-O-tetradecanoylphorbol 13-acetate (TPA) to the mouse ear or by subcutaneous injection of phospholipase A(2) or serotonin in the mouse paw. Eczema provoked on the mouse ear by repeated administration of TPA was selected as a model of chronic inflammation. The flavonoids were assayed against sheep red blood cell-induced mouse paw oedema as a model of delayed-type hypersensitivity reaction. The most active compound, both in vitro and in vivo, was tiliroside. It significantly inhibited enzymatic and non-enzymatic lipid peroxidation (IC(50)=12.6 and 28 microM, respectively). It had scavenger properties (IC(50)=21.3 microM) and very potent antioxidant activity in the DPPH test (IC(50)=6 microM). In vivo, tiliroside significantly inhibited the mouse paw oedema induced by phospholipase A(2)(ED(50)=35.6 mg/kg) and the mouse ear inflammation induced by TPA (ED(50)=357 microg/ear). Pinocembrin was the only flavonoid that exhibited anti-inflammatory activity in the sheep red blood cell-induced delayed-type hypersensitivity reaction. However, only tiliroside significantly reduced the oedema and leukocyte infiltration induced by TPA. As in the case of other flavonoids, the anti-inflammatory activity of tiliroside could be based on its antioxidant properties, although other mechanisms are probably involved.

Anti-inflammatory activity of erycristagallin, a pterocarpene from Erythrina mildbraedii.

Erycristagallin, a pterocarpene isolated from Erythrina mildbraedii, was tested in vitro for its antioxidant properties on the stable 2,2-diphenyl-1-pycryl-hydrazyl (DPPH) free radical and on the arachidonic acid metabolism. In addition, erycristagallin was tested on different experimental models of inflammation, such as the acute and chronic inflammation induced by the application of 12-O-tetradecanoylphorbol 13-acetate (TPA) on mice and the phospholipase A(2)-induced mouse paw oedema test. In the carrageenan-induced mouse paw oedema test, the ethyl acetate extract obtained from E. mildbraedii showed anti-inflammatory activity, and erycristagallin was isolated as the active principle. In vivo, erycristagallin significantly inhibited the phospholipase A(2)-induced mouse paw oedema as well as the mouse ear oedema induced by TPA (ID(50)<10 microg/ear). Moreover, it significantly reduced the chronic inflammation and leukocyte infiltration induced by repeated application of TPA. In vitro, erycristagallin inhibited the arachidonic acid metabolism via the 5-lipoxygenase pathway in rat polymorphonuclear leukocytes (IC(50)=23.4 microM), but had no effect on cyclooxygenase-1 metabolism in human platelets, while showing antioxidant activity in the DPPH test. As with other phenolics, the anti-inflammatory activity of erycristagallin may be based on its capacity to inhibit the arachidonic acid metabolism via the 5-lipoxygenase pathway.

Phenylpropanoid and phenylisoprenoid metabolites from Asteraceae species as inhibitors of protein carbonylation.

Three phenolic antioxidant and anti-inflammatory compounds: 7-methylaromadendrin, isoprenylhydroquinone glucoside, and 3.5-dicaffeoylquinic acid methyl ester, all isolated from Western Mediterranean Asteraceae species, have been studied for their inhibitory activity against protein carbonylation, a harmful post-translational modification of peptide chains associated with degenerative diseases. All compounds have proven to be effective, with 50% inhibitory concentration (IC50) values in the micromolar range, against bovine serum albumin carbonylation caused by hypochlorite, peroxynitrite, and phorbol ester-induced leukocyte oxidative burst.

Oleuropein ameliorates acute colitis in mice.

Oleuropein, the major secoiridoid in olive tree leaves, possesses a wide range of health promoting properties. It has recently been shown to exhibit anti-inflammatory activity. We have evaluated the effect of oleuropein on dextran sulfate sodium (DSS)-induced experimental colitis in mice in order to provide insight into its mechanisms of action. Oral administration of oleuropein notably attenuated the extent and severity of acute colitis while reducing neutrophil infiltration; production of NO, IL-1ß, IL-6, and TNF-α; expression of iNOS, COX-2, and MMP-9; and the translocation of the NF-κB p65 subunit to the nucleus in colon tissue. In LPS-stimulated peritoneal macrophages, the oleuropein metabolite, hydroxytyrosol, was shown to inhibit NO production, iNOS expression, NF-κB p65 subunit translocation, mRNA expression, and the release of IL-1ß, IL-6, and TNF-α. These results suggest that the effect of oleuropein on DSS-induced colitis is associated with a decrease in the production of interleukins and expression of proteins, principally through reduction of NF-κB activation.

Inhibition of ulcerative colitis in mice after oral administration of a polyphenol-enriched cocoa extract is mediated by the inhibition of STAT1 and STAT3 phosphorylation in colon cells.

We studied a polyphenol-enriched cocoa extract (PCE) with epicatechin, procyanidin B2, catechin, and procyanidin B1 as the major phenolics for its anti-inflammatory properties against dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. PCE reduced colon damage, with significant reductions in both the extent and the severity of the inflammation as well as in crypt damage and leukocyte infiltration in the mucosa. Analysis ex vivo showed clear decreases in the production of nitric oxide, cyclooxygenase-2, pSTAT-3, and pSTAT1α, with NF-κB p65 production being slightly reduced. Moreover, NF-κB activation was reduced in RAW 264.7 cells in vitro. In conclusion, the inhibitory effect of PCE on acute UC induced by DSS in mice was attenuated by oral administration of PCE obtained from cocoa. This effect is principally due to the inhibition of transcription factors STAT1 and STAT3 in intestinal cells, with NF-κB inhibition also being implicated.

Activated kRas protects colon cancer cells from cucurbitacin-induced apoptosis: the role of p53 and p21.

Cucurbitacins have been shown to inhibit proliferation in a variety of cancer cell lines. The aim of this study was to determine their biological activity in colon cancer cell lines that do not harbor activated STAT3, the key target of cucurbitacin. In order to establish the role of activated kRas in the responsiveness of cells to cucurbitacins, we performed experiments in isogenic colon cancer cell lines, HCT116 and Hke-3, which differ only by the presence of an activated kRas allele. We compared the activity of 23, 24-dihydrocucurbitacin B (DHCB) and cucurbitacin R (CCR), two cucurbitacins that we recently isolated, with cucurbitacin I (CCI), a cucurbitacin with established antitumorigenic activity. We showed that cucurbitacins induced dramatic changes in the cytoskeleton (collapse of actin and bundling of tubulin microfilaments), inhibited proliferation and finally induced apoptosis of both HCT116 and Hke-3 cells. However, the presence of oncogenic kRas significantly decreased the sensitivity of cells to the three cucurbitacins tested, CCR, DHCB and CCI. We confirmed that mutational activation of kRas protects cells from cucurbitacin-induced apoptosis using nontransformed intestinal epithelial cells with inducible expression of kRasV12. Cucurbitacins induced the expression of p53 and p21 predominantly in HCT116 cells that harbor mutant Ras. Using HCT116 cells with targeted deletion of p53 or p21 we confirmed that p53 and p21 protect cells from apoptosis induced by cucurbitacins. These results demonstrated that sensitivity of human colon cancer cell lines to cucurbitacins depends on the kRas and p53/p21 status, and established that cucurbitacins can exert antitumorigenic activity in the absence of activated STAT3.

Protein tyrosine nitration induced by heme/hydrogen peroxide: inhibitory effect of hydroxycinnamoyl conjugates.

The present study was designed to optimize the experimental conditions that govern the heme-catalyzed nitration of protein tyrosine residues by nitrite, and, within this framework, to study the effects of 3,5-dicaffeoylquinic acid and its methyl ester, both of which have been previously reported to be antioxidants and inhibitors of leukocyte functions. Although the presence of hydrogen peroxide is essential in cell-free systems, an excess of this compound was found to be detrimental, so much so that an increase in hemin concentration actually resulted in an inverse effect on the reaction, depending on the levels of fixed hydrogen peroxide. Unlike previous reports on nitrite-induced albumin tyrosine nitration, the optimal pH here was found to be 7.0. The two caffeoyl conjugates tested were found to be effective inhibitors of protein nitration, with IC50 values ranging from 20 - 30 microM, regardless of the presence of bicarbonate. For the inhibition of myeloperoxidase-catalyzed protein nitration by human polymorphonuclear leukocytes stimulated by phorbol ester, the potencies obtained were up to two times higher. This is the first time that caffeoylquinic esters have been reported as inhibitors of heme-based protein nitration.

Cucurbitacin R reduces the inflammation and bone damage associated with adjuvant arthritis in lewis rats by suppression of tumor necrosis factor-alpha in T lymphocytes and macrophages.

The aim of this study was to investigate the effects of cucurbitacin R on an experimental model of adjuvant-induced arthritis in rats. The treatment of arthritic rats with cucurbitacin R (1 mg/kg p.o. daily) modified the evolution of the clinical symptoms, whereas the histopathology of paws demonstrated a reduction in the signs of arthritis. Compared with the control group, radiography of the tibiotarsal joints of cucurbitacin R-treated rats showed a decrease in joint damage and soft tissue swelling of the footpad. The in vivo study of the expression of proinflammatory enzymes (nitric-oxide synthase-2 and cyclooxygenase-2) with the aid of the Western blot technique, and that of tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E(2) by means of enzyme-linked immunosorbent assays demonstrated a clear decrease in both the enzymes and the mediators in paw homogenates. The analysis for prostaglandin E(2), nitric oxide, and TNF-alpha production in RAW 264.7 macrophages, as well as that for TNF-alpha in human lymphocytes, indicated a reduction of all mediators. The expression of cyclooxygenase-2 was not modified in RAW 264.7 macrophages, whereas the expression of nitric-oxide synthase-2 was clearly diminished. Moreover, cucurbitacin R was found to inhibit signal transducer and activator of transcription 3 activation in the lymphocytes of both healthy and arthritic men. These experimental data on the chronic model, together with previously reported activity on acute and subchronic experimental models, justify the anti-inflammatory activity of cucurbitacin R and provide further evidence for the therapeutic potential of a group of natural products as anti-inflammatory agents.

Dihydrocucurbitacin B inhibits delayed type hypersensitivity reactions by suppressing lymphocyte proliferation.

We have studied the effects of dihydrocucurbitacin B, a triterpene isolated from Cayaponia tayuya roots, on different models of delayed type hypersensitivity (DTH) in mice, as well as on T-lymphocyte proliferation and the mediators involved. In experiments with mice, dihydrocucurbitacin B inhibited the inflammatory reactions induced by oxazolone, dinitrofluorobenzene, and sheep red blood cells, reducing both the edema and cell infiltration. Moreover, the analysis of inflamed tissues showed that dihydrocucurbitacin B reduced the presence of the most relevant cytokines implicated in these processes, including interleukin-1 beta, interleukin-4, and tumor necrosis factor-alpha. Dihydrocucurbitacin B was also found to inhibit the proliferation of phytohemagglutinin-stimulated human T lymphocytes (IC(50) = 1.48 microM), halting the cell cycle in the G(0) phase. In addition, the triterpene reduced the production of interleukin-2, interleukin-4, interleukin-10, and interferon-gamma in human T lymphocytes, and it hampered the induction of the principal cyclins involved in the cell cycle, including A(1), B(1), D(2), and E(1). Finally, dihydrocucurbitacin B was found to exert a selective inhibition on the nuclear factor of activated T cells (NFAT) in human lymphocytes without affecting the calcium influx. Taken together, these results suggest that dihydrocucurbitacin B curbs DTH reactions by inhibiting NFAT, which in turn suppresses the proliferation of the most relevant cells involved in DTH reactions, namely the T cells.

Anti-inflammatory activity of 5-O-demethylnobiletin, a polymethoxyflavone isolated from Sideritis tragoriganum.

We have studied the effect of 5- O-demethylnobiletin ( 1) on both the inflammation of mouse ears induced by repeated application of 12- O-tetradecanoylphorbol 13-acetate (TPA) and the acute mouse paw oedemas induced by carrageenan and phospholipase A (2) (PLA (2)), and determined its activity on 5-lipoxygenase (5-LOX) and elastase release/activity. Compound 1 reduced the oedema formation, cell infiltration, and tissue damage in the inflammation induced by TPA in mouse ears, along with the acute oedema induced by carrageenan in mouse paws and the acute PLA (2)-induced oedema in mouse paws. The flavone inhibited leukotriene B (4) formation in rat neutrophils and elastase release in human neutrophils, but did not reduce the expression of cyclooxygenase-2 (COX-2) in murine RAW 264.7 macrophages. These experimental results suggest that 1 may act through a direct inhibition of 5-LOX, without affecting the expression of COX-2.

Isolation of two triterpenoids and a biflavanone with anti-Inflammatory activity from Schinus molle fruits.

Three compounds with anti-inflammatory activity were isolated from Schinus molle fruits. Two of the compounds were identified as 3- epi-isomasticadienolalic acid ( 1), isomasticadienonalic acid ( 2) and chamaejasmin ( 3). Triterpenes 1 and 2, and biflavanone 3 were tested on two models of mice paw inflammation: one of acute inflammation, induced by subcutaneous injection of either phospholipase A (2) (PLA (2)) or carrageenan in the paws of mice, and one of chronic inflammation in the form of eczema, provoked by repeated administration of TPA to the ears of mice. On the PLA (2)-induced mouse paw oedema, only 2 was active (30 mg/kg, 66 % inhibition at 60 min), whereas all compounds reduced the chronic model of inflammation (48 to 26 % of swelling reduction), but only triterpenes reduced the leukocyte infiltration, measured as tissue peroxidase activity. In the case of the carrageenan-induced mouse paw oedema, only 3 led to a reduction of the swelling 3 h after challenge (50 mg/kg, 46 % oedema inhibition). In addition, 3 inhibited the LTB (4) production in rat peritoneal polymorphonuclear leukocytes with an IC (50) value of 29.8 microM, while triterpenes showed toxicity against cells at 100 microM.

Anti-inflammatory activity of two cucurbitacins isolated from Cayaponia tayuya roots.

Fractionation of an anti-inflammatory extract from Cayaponia tayuya roots yielded two active compounds, identified as 23,24-dihydrocucurbitacin B (1) and cucurbitacin R (2). Both were evaluated for their anti-inflammatory activity on several experimental models of pain and inflammation. In addition, their cytotoxicity and effects on leukotriene B4 (LTB4) formation were evaluated in rat polymorphonuclear leukocytes. Both compounds showed activity in the following models: carrageenan-induced mouse paw oedema (1, 4 mg/kg p.o., 46% inhibition at 3 h), phospholipase A2-induced mouse paw oedema (2, 3 mg/kg i.p., 61% inhibition at 60 min), serotonin-induced mouse paw oedema (1 and 2, 0.5 mg/kg s.c., 73% and 79% inhibition, respectively), 12- O-tetradecanoylphorbol 13-acetate (TPA)-induced acute ear oedema (2, 36% inhibition at 4 mg/kg p.o., and 87% inhibition at 0.1 mg/ear topically). The compounds were also active against the inflammation induced by repeated application of TPA on mouse ears, affecting both the oedema itself (1 and 2 at 0.1 mg/ear, 44% and 56% inhibition, respectively) as well as cell infiltration (68% and 69%, respectively). The activity of both compounds against oedema induced by serotonin was not modified by the glucocorticoid receptor antagonist mifepristone; however, the protein synthesis inhibitor cycloheximide abolished the anti-inflammatory response in both cases. Neither compound modified the production of LTB4 in rat polymorphonuclear leukocytes, nor did they exhibit analgesic properties at the dose assayed.