Synthesis and biological activities of 8-arylflavones

A number of 8-arylflavones have been synthesized as congeners of wogonin and evaluated for their inhibitory activities of PGE2 production. 8-Arylflavones were obtained from commercially available chrysin via two different synthetic pathways. Most 8-arylflavones exhibited much reduced inhibitory activities against COX-2 catalyzed PGE2 production compared to that of wogonin. Functional group replacement at the 8-position of wogonin from methoxy to aryl group caused loss of inhibitory activity. Our present results imply that the functional group at the 8-position of flavones seems to play very important roles for bioactivity.     

Synthetic wogonin derivatives suppress lipopolysaccharide-induced nitric oxide production and hydrogen peroxide-induced cytotoxicity

Wogonin (5,7-dihydroxy-8-methoxyflavone) has been reported to exhibit a variety of biological properties including anti-inflammatory and neuroprotective functions. In this study, biological activities of diverse synthetic wogonin derivatives have been evaluated in two experimental cell culture models. Inhibitory activities of wogonin derivatives on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV2 microglial cells and on hydrogen peroxide (H2O2)-induced neuronal cell death in SH-SY5Y human neuroblastoma were examined. Wogonin derivatives such as WS2 and WS3 showed more potent suppressive activities on LPS-induced NO production and H2O2-induced cytotoxicity than wogonin itself. In addition, thiol substitution played a minor role in enhancing the activities of the derivatives. These findings may contribute to the development of novel anti-inflammatory and neuroprotective agents derived from wogonin.     

Effect of wogonin, a plant flavone from Scutellaria radix, on the suppression of cyclooxygenase-2 and the induction of inducible nitric oxide synthase in lipopolysaccharide-treated RAW 264.7 cells

Plant flavonoids show anti-inflammatory activity both in vitro and in vivo. Some flavonoids, such as flavone derivatives, have been reported previously to inhibit nitric oxide (NO) production by suppressing inducible nitric oxide synthase (iNOS) expression. In this investigation, the effects of wogonin, a potent inhibitor of NO production among the flavonoids tested, on cyclooxygenase-2 (COX-2) induction and activity were elucidated further in connection with iNOS, using a mouse macrophage cell line, RAW 264.7. Wogonin inhibited NO and prostaglandin E(2) (PGE(2)) production from lipopolysaccharide-induced RAW cells with IC(50) values of 31 and 0.3 microM, respectively. When added after the induction of iNOS and COX-2, wogonin inhibited the formation of PGE(2) (IC(50) = 0.8 microM), but not the production of NO. Wogonin inhibited COX-2 activity directly (IC(50) = 46 microM) from the homogenate of aspirin-pretreated RAW cells, as determined by measuring [(14)C]PGE(2) formation from [(14)C]arachidonic acid. However, it did not inhibit iNOS or phospholipase A(2) activity. Western blotting showed that wogonin suppressed the induction of both iNOS and COX-2. Prednisolone also suppressed the induction of iNOS and COX-2. Whereas RU-486 (a steroid receptor antagonist) reversed the suppressive activity of prednisolone, it did not affect the suppressive activity of wogonin, suggesting that the suppressive activity of wogonin is not mediated by binding to a steroid receptor. Results from the present study demonstrated that wogonin is a direct COX-2 inhibitor, as well as an inhibitor of iNOS and COX-2 induction. Wogonin may be a potential agent for use in the treatment of inflammatory diseases.     

Wogonin attenuates endotoxin‐induced prostaglandin E2 and nitric oxide production via Src‐ERK1/2‐NFκB pathway in BV‐2 microglial cells

Microglia are the major component of intrinsic brain immune system in neuroinflammation. Although wogonin expresses anti‐inflammatory function in microglia, little is known about the molecular mechanisms of the protective effect of wogonin against microglia activation. The aim of this study was to evaluate how wogonin exerts its anti‐inflammatory function in BV2 microglial cells after LPS/INFγ administration. Wogonin not only inhibited LPS/ INFγ‐induced PGE2 and NO production without affecting cell viability but also exhibited parallel inhibition on LPS/INFγ‐induced expression of iNOS and COX‐2 in the same concentration range. While LPS/INFγ‐induced expression of P‐p65 and P‐IκB was inhibited by wogonin — only weak inhibition on P‐p38 and P‐JNK were observed, whereas it significantly attenuated the P‐ERK1/2 and its upstream activators P‐MEK1/2 and P‐Src in a parallel concentration‐dependent manner. These results indicated that the blockade of PGE2 and NO production by wogonin in LPS/INFγ‐stimulated BV2 cells is attributed mainly to interference in the Src‐MEK1/2‐ERK1/2‐NFκB‐signaling pathway. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1162–1170, 2014.     

In vitro and in vivo inhibitory activities of rutin,wogonin, and quercetin on lipopolysaccharide-induced nitric oxide and prostaglandin E(2) production

Flavonoids are widely distributed in plants, but their biological functions are still unclear. In the present study, in vitro and in vivo experiments were performed to demonstrate the inhibitory activities of rutin, wogonin, and quercetin on lipopolysaccharide-induced nitric oxide (NO) and prostaglandin E(2) production in RAW 264.7 macrophages, primary peritoneal macrophages, and Balb/c mice, respectively. In vitro results showed that wogonin and quercetin dose-dependently suppressed lipopolysaccharide-induced NO production in RAW 264.7 macrophages and primary peritoneal macrophages without a notable cytotoxic effect on either cell types associated with a decrease in inducible nitric oxide synthase (iNOS) protein expression in both cells. Rutin, at 80 microM only, had a slight but obvious inhibitory effect on lipopolysaccharide-induced NO production in primary peritoneal macrophages. Both wogonin and quercetin attenuated lipopolysaccharide-induced prostaglandin E(2) production in vitro. Intravenous injection of lipopolysaccharide (10 mg/kg, i.v.) resulted in a time-dependent induction of NO production in serum, and pretreatment with the L-arginine analog N-nitro-L-arginine methyl ester (L-NAME) blocked this induction. Intravenous pretreatment of Balb/c mice with rutin, wogonin or quercetin for 1 h followed by lipopolysaccharide treatment significantly inhibited lipopolysaccharide-induced NO production, but no inhibition of prostaglandin E(2) production was found. A decrease in iNOS protein, but not cyclooxygenase-2 protein, was detected in liver and lung specimens of lipopolysaccharide-treated Balb/c mice in the presence of rutin, wogonin or quercetin. In conclusion, data obtained both in vitro and in vivo suggest that wogonin and quercetin exert inhibitory activity on lipopolysaccharide-induced NO production through suppression of iNOS expression.     

Inhibition of prostaglandin E<Subscript>2</Subscript> production by synthetic Wogonin analogs

Effects of wogonin analogs on cyclooxygenase-2 (COX-2) catalyzed prostaglandin E₂ production on lipopolysaccharide (LPS)-induced RAW 264.7 cells were investigated. Wogonin analogs were prepared via several different synthetic pathways. Among wogonin analogs tested, 8-halogeno and 8-nitro analogs showed strong inhibitory activities against COX-2 catalyzed PGE₂ production from LPS-induced RAW 264.7 cells. Effect of wogonin was largely dependent on structural alteration of the 8-methoxy group.     

Effects of naturally occurring flavonoids on nitric oxide production in the macrophage cell line RAW 264.7 and their structure-activity relationships.

Flavonoids affect the inflammatory process of the mammalian system and possess anti-inflammatory as well as immunomodulatory activities in vitro and in vivo. Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is one of the inflammatory mediators, the effects of various naturally occurring flavonoids on NO production in LPS-activated RAW 264.7 cells were evaluated in vitro. Flavonoids such as apigenin, wogonin, luteolin, tectorigenin, and quercetin inhibited NO production, as measured by nitrite formation at 10-100 microM. The most active among 26 flavonoid derivatives tested were apigenin, wogonin, and luteolin, having IC50 values of 23, 17, and 27 microM, respectively, while AMT, a synthetic selective iNOS inhibitor, had an IC50 value of 0.09 microM. In contrast, flavanones, such as naringenin, and flavonoid glycosides, such as apiin, did not demonstrate significant inhibition up to 100 microM. These results clearly indicated that a C-2,3 double bond might be important, and that the potency of inhibition depended upon the substitution patterns of the flavonoid molecules. The inhibitory activity of flavonoids was not due to direct inhibition of iNOS enzyme activity because they did not reasonably inhibit iNOS activity, as measured by [3H]citrulline formation from [3H]arginine, up to 100 microM. In contrast, wogonin and luteolin concentration-dependently reduced iNOS enzyme expression, when measured by western blotting, at 10-100 microM. All these results clearly demonstrated that certain flavonoids inhibit NO production in lipopolysaccharide-activated RAW 264.7 cells, and their inhibitory activity might be due to reduction of iNOS enzyme expression.     

Inhibition of prostaglandin production by a structurally-optimized flavonoid derivative, 2',4',7-trimethoxyflavone and cellular action mechanism

Flavonoids possess anti-inflammatory activity in vitro and in vivo. In order to find the anti-inflammatory flavone derivatives having optimum chemical structures, various flavones were previously synthesized and evaluated for their inhibitory activity of prostaglandin E(2) (PGE(2)) production from lipopolysaccharide (LPS)-treated mouse macrophage cell line, RAW 264.7 cells. Through this screening procedure, 2',4',7-trimethoxyflavone (TMF) was selected for further pharmacological study. From the present investigation, it was found that TMF potently inhibited PGE(2) production from LPS-treated RAW cells with an IC(50) of 0.48 microM, compared to the IC(50) values of 0.07 and 1.09 microM for NS-398 and wogonin. TMF, however, did not inhibit cyclooxygenase-2 (COX-2) activity or COX-2 expression level. Instead, TMF was proved to be a phospholipase A(2) (PLA(2)) inhibitor. The IC(50) values of TMF against secretory PLA(2)-IIA (sPLA(2)-IIA) and cytosolic PLA(2) (cPLA(2)) were 70.5 and 70.4 microM, respectively. At doses of 10-250 microg/ear, TMF also showed in vivo anti-inflammatory activity by topical application against mouse croton oil-induced ear edema assay, suggesting a potential for new anti-inflammatory agent.     

Synthesis and antiinflammatory activity of 1,5-Diarylimidazoles

A number of 1,5-diarylimidazoles has been synthesized and evaluated for their inhibitory activities of COX-2 catalyzed PGE2 production. 1,5-Diarylimidazoles were obtained from imimes and p-toluenesulfonylmethyl cyanide (TosMIC). Imines were prepared from commercially available amines and aldehydes. Among the compounds tested, 1-(2,4-difluorophenyl)-5-(4-methylsulfonylphenyl)imidazole (2r) showed strong inhibitory activity, however, most diarylimidazoles exhibited little to low inhibitory activities against COX-2 catalyzed PGE2 production.     

Wogonin, baicalin, and baicalein inhibition of inducible nitric oxide synthase and cyclooxygenase-2 gene expressions induced by nitric oxide synthase inhibitors and lipopolysaccharide

We previously reported that oroxylin A, a polyphenolic compound, was a potent inhibitor of lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In the present study, three oroxylin A structurally related polyphenols isolated from the Chinese herb Huang Qui, namely baicalin, baicalein, and wogonin, were examined for their effects on LPS-induced nitric oxide (NO) production and iNOS and COX-2 gene expressions in RAW 264.7 macrophages. The results indicated that these three polyphenolic compounds inhibited LPS-induced NO production in a concentration-dependent manner without a notable cytotoxic effect on these cells. The decrease in NO production was in parallel with the inhibition by these polyphenolic compounds of LPS-induced iNOS gene expression. However, these three compounds did not directly affect iNOS enzyme activity. In addition, wogonin, but not baicalin or baicalein, inhibited LPS-induced prostaglandin E2 (PGE2) production and COX-2 gene expression without affecting COX-2 enzyme activity. Furthermore, N-nitro-L-arginine (NLA) and N-nitro-L-arginine methyl ester (L-NAME) pretreatment enhanced LPS-induced iNOS (but not COX-2) protein expression, which was inhibited by these three polyphenolic compounds. Wogonin, but not baicalin or baicalein, similarly inhibited PGE2 production and COX-2 protein expression in NLA/LPS or L-NAME/LPS-co-treated RAW 264.7 cells. These results indicated that co-treatment with NOS inhibitors and polyphenolic compounds such as wogonin effectively blocks acute production of NO and, at the same time, inhibits expression of iNOS and COX-2 genes.     

益康唑和克霉唑对血小板聚集及TXB_2和PGE_2生成的影响

益康唑,克霉唑,咪康唑和酮康唑体外抑制AA诱导兔血小板聚集比抑制ADP诱导大鼠血小板聚集的作用强。其中益康唑和克霉唑抑制AA诱聚兔血小板的IC_(50)分别是6.4及11.6μmol/L。放射免疫法测定大鼠血小板产生的TXB_2及PGE_2发现益康唑和克霉唑在5～50 nmol/L浓度下,能抑制TXB_2产生,同时增加PGE_2生成量,并呈良好的剂量效应相关。浓度为0.1～100μmol/L时,TXB_2的生成仍被抑制,而PGE_2的生成量反而逐渐降低。两药对TXB_2生成的抑制作用比Daz强。     

Inhibitory effects of baicalein and wogonin on lipopolysaccharide-induced nitric oxide production in macrophages.

In order to elucidate the mechanism of the antiinflammatory action of baicalein and wogonin, flavonoids from the root of Scutellaria baicalensis, the effects of these compounds were investigated on lipopolysaccharide-induced nitric oxide production in a macrophage-derived cell line, RAW 264.7. Baicalein (5-25 microM) and wogonin (5-50 microM) inhibited lipopolysaccharide-induced nitric oxide generation in a concentration-dependent manner. The inhibitory effect of these compounds was observed only when they were added at the start of cell incubation soon after the stimulation with lipopolysaccharide. Baicalein (25 microM) and wogonin (25 microM) also inhibited protein expression of inducible nitric oxide synthase. This inhibitory effect of wogonin was stronger than that of baicalein, which agrees with the result that wogonin showed stronger inhibition of nitric oxide production than baicalein. These results suggest that baicalein and wogonin attenuate lipopolysaccharide-stimulated nitric oxide synthase induction in macrophages and thus may help to explain the antiinflammatory action of these flavonoid compounds.     

Isatins inhibit cyclooxygenase-2 and inducible nitric oxide synthase in a mouse macrophage cell line

Isatin is a versatile compound with a diversity of effects. We designed to investigate the inhibitory effect of isatin derivatives on lipopolysaccharide/interferon-gamma-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins, production of prostaglandin E(2) (PGE(2)), nitric oxide (NO), tumor necrosis factor (TNF-alpha), and their capacity to scavenge NO. Isatins inhibit TNF-alpha production and iNOS and COX-2 protein expression resulting on reduced levels of NO and PGE(2). Our results indicate isatin and it derivatives as inhibitors of iNOS and COX-2 enzymes, which might be used as anti-inflammatory and antitumoral agents.     

Inhibitory Effects of Baicalein and Wogonin on Lipopolysaccharide-Induced Nitric Oxide Production in Macrophages

Abstract: In order to elucidate the mechanism of the antiinflammatory action of baicalein and wogonin, flavonoids from the root of Scutellaria baicalensis, the effects of these compounds were investigated on lipopolysaccharide-induced nitric oxide production in a macrophage-derived cell line, RAW 264.7. Baicalein (5–25 μM) and wogonin (5–50 μM) inhibited lipopolysaccharide-induced nitric oxide generation in a concentration-dependent manner. The inhibitory effect of these compounds was observed only when they were added at the start of cell incubation soon after the stimulation with lipopolysaccharide. Baicalein (25 μM) and wogonin (25 μM) also inhibited protein expression of inducible nitric oxide synthase. This inhibitory effect of wogonin was stronger than that of baicalein, which agrees with the result that wogonin showed stronger inhibition of nitric oxide production than baicalein. These results suggest that baicalein and wogonin attenuate lipopolysaccharide-stimulated nitric oxide synthase induction in macrophages and thus may help to explain the antiinflammatory action of these flavonoid compounds.     

Inhibition of prostalglandin E2 production by 2'-hydoxychalcone derivatives and the mechanism of action

The effects of 14 synthetic 2'-hydroxychalcone derivatives on prostaglandin E2 (PGE2) production in rat peritoneal macrophages stimulated by the protein kinase C activator, 12-O-tetradecanoylphorbol 13-acetate (TPA), were examined to clarify the structure-activity relationship. 2',4-Dihydroxy-4'-methoxychalcone (compound 3), 2',4-dihydroxy-6'-methoxychalcone (compound 8) and 2'-hydroxy-4'-methoxychalcone (compound 9) suppressed PGE2 production more potently than the other compounds. The IC50 (50% Inhibitory concentration) value for compounds 3, 8 and 9 was calculated to be 3 microM. The activity of cyclooxygenase (COX)-1 was inhibited slightly by compound 9, but that of COX-2 was not inhibited. At concentrations that inhibited the production of PGE2, compound 9 had no effect on the release of radioactivity from [3H]arachidonic acid-labelled macrophages stimulated by TPA. Western-blot analysis revealed that the induction of COX-2 protein by TPA was inhibited by compound 9 in parallel with the inhibition of PGE2 production. Compounds 3 and 8 had similar effects. These findings suggest that 4'-methoxyl and 6'-methoxyl groups are required for the expression of more potent inhibitory activity against PGE2 production, and that the inhibition of PGE2 production by these 2'-hydroxychalcone derivatives is due to the inhibition of TPA-induced COX-2 protein expression.     

Protective effects of baicalein and wogonin against benzo[a]pyrene- and aflatoxin B(1)-induced genotoxicities.

To evaluate the protective effects of baicalein and wogonin against benzo[a]pyrene- and aflatoxin (AF) B(1)-induced toxicities, the effects of these flavonoids on the genotoxicities and oxidation of benzo[a]pyrene and AFB(1) were studied in C57BL/6J mice. Baicalein and wogonin reduced benzo[a]pyrene and AFB(1) genotoxicities as monitored by the umuC gene expression response in Salmonella typhimurium TA1535/pSK1002. Baicalein added in vitro decreased liver microsomal benzo[a]pyrene hydroxylation (AHH) activity with an ic(50) of 33.9 +/- 1.4 microM at 100 microM benzo[a]pyrene. Baicalein also inhibited AFQ(1) and AFB(1)-epoxide formation from AFB(1) (50 microM) oxidation (AFO) with ic(50) values of 22.8 +/- 1.4 and 5.3 +/- 0.8 microM, respectively. However, the in vitro inhibitory effects of wogonin on AHH and AFO activities in liver microsomes were less than those of baicalein as inhibition by 500 microM wogonin was only about 51-65%. Treatment of mice with liquid diets containing 5 mM baicalein and wogonin resulted in 22 and 49% decreases in hepatic AHH activities, respectively. Baicalein treatment resulted in 39 and 32% decreases in AFQ(1) and AFB(1)-epoxide formation from liver microsomal AFO, respectively. Wogonin treatment resulted in 39 and 47% decreases in AFQ(1) and AFB(1)-epoxide formation, respectively. A 1-week pretreatment with wogonin significantly decreased hepatic DNA adduct formation in mice treated with 200 mg/kg of benzo[a]pyrene via gastrogavage. These in vitro and in vivo effects suggested that baicalein and wogonin might have beneficial effects against benzo[a]pyrene- and AFB(1)-induced hepatic toxicities and that wogonin had a stronger protective effect in vivo.     

The role of adenosine A(2) receptors in the regulation of TNF-alpha production and PGE(2) release in mouse peritoneal macrophages

The adenosine A(2) receptors are known to mediate most of the anti-inflammatory activities of adenosine. In lipopolysaccharides (LPS)-stimulated macrophages adenosine strongly inhibits TNF-alpha release, but may also enhance PGE(2) generation. The aims of this study were to determine the relative contributions of the A(2A) and A(2B) receptor subclasses in these two effects and to determine whether the enhanced release of PGE(2) contributes to the inhibition of TNF-alpha release. In LPS-stimulated mouse macrophages, adenosine potently inhibited TNF-alpha production and also potentiated PGE(2) release, though less potently (IC(50)=250 nM vs EC(50) approximately 8 microM, respectively). The non-selective adenosine receptor agonist NECA, and the selective A(2A) receptor agonist CGS21680 also inhibited TNF-alpha production even more potently (IC(50)=4.8 and 2.3 nM, respectively). NECA, but not CGS21680, also enhanced PGE(2) production. The selective A(2A) receptor antagonist ZM241385 (30 nM), but not the selective A(2B) receptor antagonist MRS1754 (30 nM), blocked the inhibitory effect of NECA and CGS21680 on TNF-alpha release. On the other hand, MRS1754, but not ZM241385, abolished the PGE(2) potentiating effect of NECA. Pre-treatment with indomethacin (1 microM) abolished adenosine-induced PGE(2) release enhancement but did not prevent the inhibition of TNF-alpha release. These results show that in this system, the inhibition of TNF-alpha release by adenosine is mediated by the A(2A) receptors whereas the enhancement of PGE(2) release appears to be mediated by the A(2B) receptors. The results also show that while exogenous PGE(2) is a potent inhibitor of TNF-alpha release, the enhanced PGE(2) release induced by adenosine does not appear to contribute to the inhibition of TNF-alpha release.     

Anti-inflammatory effects of cordycepin via suppression of inflammatory mediators in BV2 microglial cells

Cordyceps militaris, a traditional medicinal mushroom, produces the bioactive compound cordycepin (3'-deoxyadenosine). Although cordycepin has been shown to have pharmacological, immunological stimulating, anti-cancer, and anti-inflammatory activities, its activities and cellular mechanisms during microglial activation have yet to be elucidated. Thus, we evaluated the anti-inflammatory effect of cordycepin on the production of inflammatory mediators in lipopolysaccharide (LPS)-stimulated murine BV2 microglia. We also investigated the effects of cordycepin on LPS-induced nuclear factor-kappaB (NF-κB) activation and on phosphorylation of mitogen-activated protein kinases (MAPKs). After LPS stimulation, nitric oxide (NO), prostaglandin E? (PGE?), and pro-inflammatory cytokine production was detected in BV2 microglia. However, we found that cordycepin significantly inhibited the excessive production of NO, PGE?, and pro-inflammatory cytokines in a concentration-dependent manner without causing cytotoxicity. In addition, cordycepin suppressed NF-κB translocation by blocking IkappaB-α (IκB-α) degradation and inhibited the phosphorylation of Akt, ERK-1/2, JNK, and p38 kinase. Our results indicate that the inhibitory effect of cordycepin on LPS-stimulated inflammatory mediator production in BV2 microglia is associated with the suppression of the NF-κB, Akt, and MAPK signaling pathways. Therefore, cordycepin may be useful in treating neurodegenerative diseases by inhibiting inflammatory mediator production in activated microglia.     

新型查耳酮衍生物的合成及其初步抗蛋白酪氨酸 激酶(PTKs)活性研究

目的 设计合成一系列全新的查耳酮类衍生物,并初步测试其蛋白酪氨酸激酶（PTKs）抑制活性。方法 以间二甲苯为原料,经硝化、还原、水解、甲氧甲基保护等反应得到中间体取代苯乙酮,该中间体再与取代苯甲醛发生羟醛缩合反应后脱保护基得到目标化合物。采用酶联免疫吸附法（ELISA）,以金雀异黄素为阳性对照,对目标化合物进行体外 PTKs 抑制活性检测。 结果与结论 合成了 10 个查耳酮衍生物,其中 9 个是未见报道的新化合物,10 个化合物的结构经核磁共振氢谱和质谱确证。化合物 6a 及新化合物 6b、6c 和 6d 对 PTKs 具有良好的抑制活性。     

Pharmacological studies of the new antiinflammatory agent 3-formylamino-7-methylsulfonylamino-6-phenoxy-4'-1-benzopyran-4-o ne. 2nd communication: effect on the arachidonic acid cascades.

The in vitro and in vivo effects of 3-formylamino-7-methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-on e (T-614, CAS 123663-49-0), a new antiinflammatory agent, on arachidonic acid metabolism were investigated in comparison with those of reference drugs. Although the inhibitory effect of T-614 on the synthesis of prostaglandins by rabbit renal microsomes was very weak (IC50 of 58 micrograms/ml), T-614 effectively inhibited the prostaglandin E2 (PGE2) generation by mouse fibroblasts stimulated with bradykinin with an IC50 value of 0.47 micrograms/ml. The suppressive effect of T-614 on the PGE2 generation in fibroblasts was also found when cells were stimulated with Ca ionophore A23187, but not when induced with arachidonic acid. T-614 suppressed the A23187-induced PGE2 generation by rat macrophages, but not the leukotriene B4 production. In addition, 5-lipoxygenase activities in guinea-pig peritoneal exudated cells were not inhibited. In in vivo experiments, at doses of more than 1 mg/kg, T-614 reduced the PGE2 contents in inflammatory exudate of rat carrageenin-sponge type inflammation, but it was almost inactive in inhibiting gastric prostaglandins production up to 100 mg/kg. T-614 also did not affect the urinary PGE2 excretion in rats, and slightly inhibited the thromboxane synthesis in rat blood. Furthermore, the convulsion-induced increase of PGE2 in mouse brain was inhibited by T-614. These data suggest that T-614 inhibits the production of cyclooxgenase-mediated products with apparently different mode from classical non-steroidal antiinflammatory drugs, and may partly explain the discrepancy in pharmacological properties between this compound and other drugs.