Croton Oil-induced Ear Edema Research Articles

Extracts and constituents of Lavandula multifida with topical anti-inflammatory activity

The topical anti-inflammatory activity of the ethanol and aqueous extracts from the aerial parts of Lavandula multifida L. (Lamiaceae), used in the Moroccan traditional medicine, was investigated by inhibition of the Croton oil-induced ear edema in mice. The biological assay revealed a dose-dependent anti-inflammatory activity for the ethanol extract, while the aqueous one was less active. Bioassay-guided fractionation of the ethanol extract led to identify four triterpenic acids of oleanane series, four pimarane and one iso-pimarane diterpenes, as well as the phenolic monoterpene carvacrol and its glucoside. Some of these compounds revealed an anti-inflammatory activity comparable to that of indomethacin.

Anti-inflammatory Properties of Entada abyssinica. Leaves

The effects of the defatted methanol extract of Entada abyssinica. Steud. ex A. Rich leaves on some models of inflammation were investigated. The analgesic property of the plant extract was also tested on acetic acid–induced writhing, as well as formalin-induced paw licking, in mice. The antipyretic effect was evaluated using yeast-induced hyperpyrexia in mice. At doses of 50–200 mg/kg, the extract produced significant (p < 0.05) inhibition of leukocyte migration after intraperitoneal injection of carrageenan in rats. A topical anti-inflammatory effect was produced by 20 mg/ear of the extract, as demonstrated by inhibition of croton oil–induced ear edema in mice. The analgesic property of the plant extract was observed by inhibition of acetic acid–induced writhing and paw licking induced by formalin in mice. The extract, however, exhibited no antipyretic activity. This study further established the anti-inflammatory activity of E. abyssinica., in addition to its analgesic effect.

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.

Anti-inflammatory and related pharmacological activities of cultured mycelia and fruiting bodies of Cordyceps militaris

This study aimed to elucidate pharmacological activities of Cordyceps militaris. The 70% ethanolic extracts of cultured mycelia (CME) and fruiting bodies (FBE) of Cordyceps militaris were prepared. CME was able to directly scavenge the stable free radical diphenyl-2-picrylhydrazyl (DPPH), indicating its antioxidant activity. Both CME and FBE showed topical anti-inflammatory activity in the croton oil-induced ear edema in mice. CME was found to contain acute anti-inflammatory activity, which was evaluated using the carrageenin-induced edema, and also strong antinociceptive activity in writhing test. CME and FBE contain potent inhibitory activity on the chick embryo chorioallantoic membrane (CAM) angiogenesis in a dose-dependent manner. Cordycepin, a metabolite of Cordyceps militaris, appeared to be at least partly responsible for its anti-inflammatory and anti-angiogenic activities. CME concentration-dependently inhibited the NO production and iNOS expression upon stimulation by lipoposaccharide in RAW 264.7, a murine macrophage cell line. In brief, we demontrate that Cordyceps militaris possesses anti-inflammatory and antinociceptive activites, and related antioxidant, anti-angiogenic, and NO production-inhibitory activities.

Antiinflammatory activity of Synurus deltoides

Synurus deltoides Aiton, Nakai, is an edible plant that has been used as a folk medicine for treating inflammatory disorders. This investigation was carried out to establish the antiinflammatory activity of this plant material using a 75% ethanol extract from the aerial part of S. deltoides. Against the acute inflammatory animal model of mouse croton oil-induced ear oedema assay, the extract did not show significant inhibition at 100-800 mg/kg by oral administration. On the other hand, the extract showed considerable inhibition against the chronic inflammatory animal model of rat adjuvant-induced arthritis (25% inhibition at 100 mg/kg/day) while prednisolone exerted 40% inhibition at 10 mg/kg/day. In addition, S. deltoides possessed strong analgesic activity (IC50 = 50 mg/kg) in the acetic acid-induced writhing test. From the extract, ursolic acid and scopoletin were successfully isolated and their contents were found to be 0.31% and 0.37% (w/w), respectively, based on the dried extract by HPLC analysis. All the results obtained indicate that this plant material may be used beneficially as an antiinflammatory agent having analgesic action.

Evaluation of the antioedematogenic, free radical scavenging and antimicrobial activities of aerial parts of Tillandsiastreptocarpa Baker – Bromeliaceae

The crude methanolic extract of the aerial parts of Tillandsia streptocarpa was investigated for their acute toxicity and antioedematogenic, antioxidant and antimicrobial activities. Also, the antioedematogenic activity of the hexane fraction resulting from the partition of the crude methanolic extract was evaluated. The methanolic extract and the hexane fraction showed significant ( P < 0.05) inhibition of ear oedema, observed at 2 mg/ear in the croton oil-induced mice ear oedema test. In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging test, a high reactivity and potent antioxidant effect (IC 50 = 0.0056%, w/v) were observed for the methanolic extract. The antimicrobial activity assay showed that the crude methanolic extract was inactive toward Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans, C. parapsilosis, C. krusei and C. tropicalis (MIC > 500 μg/ml). The methanolic extract showed no toxic effect on mice at a single dose of 2000 mg/kg (p.o). Common side effects including mild diarrhoea, loss of weight and depression were not recorded. The compounds cycloartenol, 4′,5-dihydroxy-3′,7-dimethoxyflavanone and a mixture of the steroids stigmasterol, β-sitosterol and campesterol, were isolated from the hexane fraction and identified by spectroscopic methods.

Antiinflammatory effects of genipin, an active principle of gardenia

Genipin, the aglycone of geniposide, is metabolically produced from the geniposide in body tissues. The purpose of this study is to clarify some pharmacological actions of genipin. Genipin showed concentration-dependent inhibition on lipid peroxidation induced by Fe ++/ascorbate in rat brain homogenate. Genipin exhibited significant topical antiinflammatory effect shown as an inhibition of croton oil-induced ear edema in mice. Nitric oxide (NO) synthesis by inducible nitric oxide synthase (iNOS) is increased in inflammatory diseases and leads to cellular injury. Genipin concentration-dependently (50–300 μM) inhibited NO production and iNOS expression upon stimulation by lipopolysaccharide/interferon-γ (IFN-γ) in RAW 264.7, a murine macrophage cell line. Genipin markedly blocked lipopolysaccharide-evoked degradation of inhibitor-κB-β (IκB-β), indicating that it exhibits inhibitory effect on NO production through the inhibition of nuclear factor-κB (NF-κB) activation. It was also shown to contain potent antiangiogenic activity in a dose-dependent manner, which was detected by chick embryo chorioallantoic membrane assay. In summary, we demonstrate that genipin possesses antiinflammatory and is a specific hydroxyl radical scavenger. Its antiangiogenic and NO production-inhibitory properties are also presented.

In vivo anti-inflammatory activity of Alchornea cordifolia (Schumach. &amp; Thonn.) M�ll. Arg. (Euphorbiaceae)

Alchornea cordifolia (Schumach. & Thonn.) Müll. Arg. (Euphorbiaceae) is a widely distributed plant in Africa. It is used in the traditional medicine of many African countries for the treatment of bacterial, fungal, parasitic and inflammatory disorders. Aqueous decoction and methanol leaf extracts were tested for their ability to reduce Croton oil-induced oedema in the mouse ear, after topical application. The methanol leaf extract dose-dependently inhibited the Croton oil-induced ear oedema in mice (ID50 < 500 μg/cm2). A bio-assay guided liquid–liquid fractionation of this methanol extract gave four active fractions: water insoluble (F1), hexane (F2), ethyl acetate (F3) and water (F4). The hexane fraction showed a very high activity (42% inhibition at 0.7 μg/cm2) as compared to the control. The other fractions were less active (F1: 56% at 506.2 μg/cm2; F3: 57% at 289.3 μg/cm2; F4: 32% for 203.8 μg/cm2) while indomethacin gave 49% of inhibition at 90 μg/cm2. The activity of F1 and F3 may be at least in part explained by the presence of anti-inflammatory flavonoids (hyperoside and quercitrin, quercitrin being identified in the plant for the first time) while the activity was not correlated to the tannin contents. None of these compounds were detected in the most active F2 fraction. These results support the reported traditional use of this plant against topical inflammatory disorders.

Anti-inflammatory and related pharmacological activities of the n-BuOH subfraction of mushroom Phellinus linteus

This study aimed to elucidate the anti-inflammatory and related activities of mushroom Phellinus linteus. The results show that the EtOH extract of Phellinus linteus (PLE) dose-dependently inhibited the mouse ear edema induced by croton oil. Among PLE subfractions, the n-BuOH subfraction showed highest anti-inflammatory activity in croton oil-induced ear edema test. The n-BuOH subfraction also showed highest inhibitory activity on the chick embryo chorioallantoic membrane (CAM) angiogenesis in a dose-dependent manner. PLE could significantly reduce the number of writhing induced by acetic acid in mice, indicating that PLE possesses potent antinociceptive effect mediated by its anti-inflammatory activity. Mycelial extract of six different Phellinus strains were found to contain anti-angiogenic activity in the CAM assay. These results suggest that Phellinus linteus has anti-inflammatory and antinociceptive activities, in addition to its anti-angiogenic activity.

In vivo anti-inflammatory activity of Alchornea cordifolia (Schumach. & Thonn.) Müll. Arg. (Euphorbiaceae)

Alchornea cordifolia (Schumach. & Thonn.) Müll. Arg. (Euphorbiaceae) is a widely distributed plant in Africa. It is used in the traditional medicine of many African countries for the treatment of bacterial, fungal, parasitic and inflammatory disorders. Aqueous decoction and methanol leaf extracts were tested for their ability to reduce Croton oil-induced oedema in the mouse ear, after topical application. The methanol leaf extract dose-dependently inhibited the Croton oil-induced ear oedema in mice (ID 50 < 500 μg/cm 2). A bio-assay guided liquid–liquid fractionation of this methanol extract gave four active fractions: water insoluble (F1), hexane (F2), ethyl acetate (F3) and water (F4). The hexane fraction showed a very high activity (42% inhibition at 0.7 μg/cm 2) as compared to the control. The other fractions were less active (F1: 56% at 506.2 μg/cm 2; F3: 57% at 289.3 μg/cm 2; F4: 32% for 203.8 μg/cm 2) while indomethacin gave 49% of inhibition at 90 μg/cm 2. The activity of F1 and F3 may be at least in part explained by the presence of anti-inflammatory flavonoids (hyperoside and quercitrin, quercitrin being identified in the plant for the first time) while the activity was not correlated to the tannin contents. None of these compounds were detected in the most active F2 fraction. These results support the reported traditional use of this plant against topical inflammatory disorders.

Black cumin seed essential oil, as a potent analgesic and antiinflammatory drug.

The steam-distilled essential oil of Iranian black cumin seed (Nigella sativa L.) was investigated for its composition and analgesic and antiinflammatory properties. After oil analysis by GC/MS, 20 compounds were identified in the oil, obtained in 0.4% (v/w) yield. Among them, para-cymene (37.3%) and thymoquinone (13.7%) were the major components. Acetic acid-induced writhing, formalin and light tail flick tests were used for assessment of analgesic activity. Antiinflammatory activity was evaluated using carrageenan-induced paw oedema in rats and croton oil-induced ear oedema in mice. Black cumin seed essential oil (BCSEO) was found to produce a significant analgesic effect in acetic acid-induced writhing, formalin and light tail flick tests. Naloxone, an opioid antagonist, could not reverse the analgesic effect observed in the formalin test. Although oral administration of BCSEO at doses of 100, 200 and 400 micro L/kg did not exert a significant antiinflammatory effect in the carrageenan test, i.p. injection of the same doses significantly (p < 0.001) inhibited carrageenan-induced paw oedema. BCSEO at doses of 10 and 20 micro L/ear could also reduce croton oil-induced oedema. It seems that mechanism(s) other than opioid receptors is (are) involved in the analgesic effect of BCSEO since naloxone could not reverse this effect. Both systemic and local administration of BCSEO showed antiinflammatory activity. Thymoquinone, as one of the major components of BCSEO, probably has an important role in these pharmacological effects.

Acute and topic anti-edematogenic fractions isolated from the seeds of Pterodon pubescens.

We previously demonstrated that alcoholic extracts from Pterodon pubescens Benth. (Sucupira branca, Leguminosae) seeds exhibit anti-arthritic activity. In the present work we show that the oleaginous extract obtained from P. pubescens seeds (OEP) exhibits acute or topic anti-edematogenic activity when tested in carrageenan-induced paw edema or in croton oil-induced ear edema assays, respectively. Four fractions were obtained from OEP by sequential liquid-liquid extraction. The anti-edematogenic properties were predominant in the hexanic fraction, which was further fractionated by HPLC, yielding three sub-fractions (PF1.1, PF1.2 and PF1.3). PF1.1 and PF1.3 showed potent acute and topic anti-edematogenic activity. The PF1.2 sub-fraction, although not active in the carrageenan assay, exhibited a potent anti-edematogenic activity in the croton oil-induced ear edema. This sub-fraction shows a maximum efficacy similar to indometacin in a lower dose. The PF1.1 sub-fraction presented a complex mixture containing furane diterpene derivatives of vouacapan. PF1.2 consists of a single substance, geranylgeraniol, as determined by GC/MS and NMR, while PF1.3 contains farnesol.

Anti-inflammatory activity of Sedum kamtschaticum

Sedum kamtschaticum Fischer (Crassulaceae) has been used as a folk medicine in North-East Asia for treating inflammatory disorders. The present investigation was carried out to establish in vivo anti-inflammatory activity and cyclooxygenase-2 modulating activity of this plant material. The methanol extract of Sedum kamtschaticum significantly inhibited mouse croton oil-induced ear edema (24–47% inhibition at 50–400 mg/kg) and rat paw edema (24–30% inhibition at 400–800 mg/kg) by oral administration. Prednisolone (10 mg/kg) showed 54 and 36% inhibition in the same animal models, respectively. Sedum kamtschaticum also showed significant inhibitory activity against mouse ear edema induced by multiple treatment of phorbol ester for 3 days. In addition, Sedum kamtschaticum exhibited potent analgesic activity against mouse acetic acid-induced writhing (IC 50=125 mg/kg), while aspirin (200 mg/kg) showed 57% inhibition. Using lipopolysaccharide-treated RAW 264.7 cells, down-regulation of cyclooxygense-2 expression was found to be one of the cellular action mechanisms of anti-inflammation by Sedum kamtschaticum.

Anti-inflammatory and anticoagulant activities of lycopene in mice

The anti-inflammatory and anti-coagulant activities of lycopene, the most abundant carotenoid in tomato, were evaluated using mouse models. Lycopene was provided in the form of oleoresin. The croton oil-induced mouse ear oedema model was used to study the anti-inflammatory activity, while the glass slide method was used to evaluate the anti-coagulant activity. Administration of lycopene for four days was associated with decreased swelling of the treated ear with an efficiency comparable to that of amoxycillin, a well-known anti-inflammatory agent. In addition, lycopene increased the coagulation time (CT). These preliminary results suggested that the health-promoting roles of lycopene could be associated with its anti-inflammatory and anti-coagulant activities.

Anti-inflammatory effect of Solanum lycocarpum fruits.

The croton oil-induced mouse ear oedema test, acetic acid-induced abdominal writhing, and carrageenan-induced peritonitis were used to study the anti-inflammatory effects of the crude ethanol extract and its alkaloid fraction from Solanum lycocarpum fruits. The alkaloid fraction induced a dose-dependent reduction in ear oedema formation and leukocyte migration, suggesting that S. lycocarpum fruits may contain steroidal alkaloids accounting for the anti-inflammatory effect of the crude ethanol extract.

Effects of valeryl salicylate, a COX-1 inhibitor, on models of acute inflammation in mice

The effect of valeryl salicylate (VS), an inhibitor of cyclooxygenase-1 (COX-1), was evaluated in arachidonic acid or croton oil-induced ear oedema and carrageenan-induced paw oedema in mice. Ear oedema was induced by topical administration of arachidonic acid (2 mg per ear; 20 μl) or croton oil (1 mg per ear; 20 μl) to the inner surface of the left ear and the change in the ear’s thickness was measured with a precision micrometer (Fisher, USA). VS significantly inhibited the arachidonic acid ear oedema after l h at doses of 1.5–45 μg per ear; however, only at the dose of 45 μg per ear was it able to significantly reduce the croton oil-induced oedema at 6 h. Paw oedema was induced by the injection of 25 μl of 1% carrageenan into the plantar aponeurosis of the right hind paw. The oedema was evaluated at 0.5, 1, 2, 4, 24, 48 and 72 h. Previously in our experiments, we observed two peaks in paw oedema formation: one at 2 h, in the early phase (0–4 h), and the other, occurring at 48 h after carrageenan injection, in the late phase (24–72 h). The pre-treatment with VS significantly reduced the paw oedema at 2 h, the same effect observed with celecoxib and indomethacin treatments. At 24 h, VS did not inhibit oedema but significantly increased it mainly at 48 h after carrageenan injection. These results showed that VS was pharmacologically active in these models and suggest that COX-1 may participate in the early and late phases of inflammation in the models studied.

Anti-oxidative, anti-inflammatory and hepato-protective effects of Ligustrum robustum

Aqueous extract of processed leaves of Ligustrum robustum could dose-dependently scavenge superoxide radicals, inhibit lipid peroxidation, and prevent AAPH-induced hemolysis of red blood cells. In comparison with green tea, oolong tea and black tea, processed leaves of L. robustum exhibited comparable antioxidant potency in scavenging superoxide radicals and in preventing red blood cell hemolysis. By activity-guided fractionation, a glycoside-rich fraction named fraction B2 was separated and demonstrated to possess strong antioxidant effect. It was evaluated for its anti-inflammatory and hepato-protective activities. A single oral dose of fraction B2 at 0.5 g/kg could provide 51.5% inhibition on the vascular permeability change induced by intraperitoneal injection of acetic acid, but it could not inhibit croton oil-induced ear edema. On the other hand, fraction B2 exhibited moderate hepato-protective effect. Intragastric application of fraction B2 at 1.25, 2.5 or 5 g/kg 6 h after carbon tetrachloride administration could reduce the elevations of serum levels of aminotransferases (AST and ALT). Also, liver integrity was preserved, as liver sections from rats post-treated with fraction B2 showed a milder degree of fatty accumulation and necrosis. These results offer partial support to the traditional uses of the leaves of L. robustum as Ku-Ding-Cha.

Effects of sophoraflavanone G, a prenylated flavonoid from Sophora flavescens, on cyclooxygenase-2 and in vivo inflammatory response.

Previously, several prenylated flavonoids having a C-8 lavandulyl moiety were found to inhibit cyclooxygenase-1 (COX-1) as well as 5-lipoxygenase (5-LOX), and sophoraflavanone G was the most potent inhibitor against these eicosanoid generating enzymes among 19 prenylated flavonoids tested. In this investigation, effects of sophoraflavanone G on COX-2 induction from RAW 264.7 cells and in vivo inflammatory response were studied. Sophoraflavanone G inhibited prostaglandin E2 (PGE2) production from lipopolysaccharide (LPS)-treated RAW cells by COX-2 down-regulation at 1-50 uM. Other prenylated flavonoids including kuraridin and sanggenon D also down-regulated COX-2 induction at 10-25 uM, while kurarinone and echinoisoflavanone did not. In addition, sophoraflavanone G showed in vivo anti-inflammatory activity against mouse croton oil-induced ear edema and rat carrageenan paw edema via oral (2-250 mg/kg) or topical administration (10-250 microg/ear). Although the potencies of inhibition were far less than that of a reference drug, prednisolone, this compound showed higher anti-inflammatory activity when applied topically, suggesting a potential use for several eicosanoid-related skin inflammation such as atopic dermatitis.

Screening of the topical anti-inflammatory activity of some Central American plants

Hexane, chloroform and methanol extracts of seven herbal drugs used in the folk medicine of Central America against skin disorders (Aristolochia trilobata leaves and bark, Bursera simaruba bark, Hamelia patens leaves, Piper amalago leaves, and Syngonium podophyllum leaves and bark) were evaluated for their topical anti-inflammatory activity against the Croton oil-induced ear oedema in mice. Most of the extracts induced a dose-dependent oedema reduction. The chloroform extract of almost all the drugs exhibited interesting activities with ID50 values ranging between 108 and 498 μg/cm2, comparable to that of indomethacin (93 μg/cm2). Therefore, the tested plants are promising sources of principles with high anti-inflammatory activity.

Effects of Ginkgetin from Ginkgo biloba Leaves on cyclooxygenases and in vivo skin inflammation.

Ginkgetin, a biflavone from Ginkgo biloba leaves, was previously reported to be a phospholipase A2 inhibitor and this compound showed the potent antiarthritic activity in rat adjuvant-induced arthritis as well as analgesic activity. This investigation was carried out to find effects on cyclooxygenase (COX)-1 and -2 including an in vivo effect. Ginkgetin (1 - 10 microM) and the biflavonoid mixture (10 - 50 microg/ml), mainly a 1 : 1 mixture of ginkgetin and isoginkgetin, from G. biloba leaves, inhibited production of prostaglandin E2 from lipopolysaccharide-induced RAW 264.7 cells. This inhibition was mediated, at least in part, by down-regulation of COX-2 expression, but not by direct inhibition of COX-1 or COX-2 activity. Down-regulation of COX-2 by ginkgetin was also proved in the dorsal skin of ICR mouse treated by 12-O-tetradecanoylphorbol 13-acetate (TPA). At total doses of 1,000 microg/site on the dorsal skin (15 mm x 15 mm), ginkgetin inhibited prostaglandin E2 production by 65.6 % along with a marked suppression of COX-2 induction. In addition, ginkgetin and the biflavonoid mixture (100 - 1,000 microg/ear) dose-dependently inhibited skin inflammation of croton oil induced ear edema in mice by topical application. The present study suggests that ginkgetin from G. biloba leaves down-regulates COX-2 induction in vivo and this down-regulating potential is associated with an anti-inflammatory activity against skin inflammatory responses.