Multiple topical applications of arachidonic acid to mouse ears induce inflammatory and proliferative changes

Solidagenone from Solidago chilensis Meyen inhibits skin inflammation in experimental models

Solidagenone (SOL) is a labdane-type diterpenoid found in Solidago chilensis, a plant traditionally used to treat skin diseases, kidney pain and ovarian inflammation. In this study, the topical anti-inflammatory activity of SOL was evaluated using in vivo and in silico assays. Croton oil-, arachidonic acid (AA)- and phenol-induced ear oedema mouse models were applied in the in vivo studies. Myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAG) activities and tumour necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO) levels were determined, as well as histopathological analyses were conducted. Interaction profiles between SOL and cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), glucocorticoid receptor, estradiol-17-β-dehydrogenase and prostaglandin-E(2)-9-reductase were established using molecular docking. SOL significantly inhibited croton oil-, AA- and phenol-induced ear oedema (P < .001) at doses of 0.1, 0.5 and 1.0 mg/ear. The MPO and NAG activities and TNF-α, IL-6 and NO levels were decreased (P < .001). The histopathological data revealed that inflammatory parameters (oedema thickness, leucocyte infiltration and vasodilatation) were reduced by treatment with SOL at doses of 0.1, 0.5 and 1.0 mg/ear. The docking study showed that SOL interacts with COX-1 and prostaglandin-E(2)-9-reductase through hydrogen bonding, inhibiting these enzymes. These results indicate that SOL may be a promising compound for the treatment of cutaneous inflammatory disorders and has potential as a topical anti-inflammatory agent.

Development of Pranoprofen Loaded Nanostructured Lipid Carriers to Improve Its Release and Therapeutic Efficacy in Skin Inflammatory Disorders

Pranoprofen (PF)-loaded nanostructured lipid carriers (NLCs), prepared using a high-pressure homogenization method, have been optimized and characterized to improve the biopharmaceutical profile of the drug. The optimized PF-NLCs exhibited physicochemical characteristics and morphological properties that were suitable for dermal application. Stability assays revealed good physical stability, and the release behavior of PF from these NLCs showed a sustained release pattern. Cell viability results revealed no toxicity. Ex vivo human skin permeation studies in Franz diffusion cells were performed to determine the influence of different skin penetration enhancers (pyrrolidone, decanol, octanoic acid, nonane, menthone, squalene, linoleic acid, and cineol) on skin penetration and retention of PF, being the highest dermal retention in the presence of linoleic acid. The selected formulations of NLCs exhibited a high retained amount of PF in the skin and no systemic effects. In vivo mice anti-inflammatory efficacy studies showed a significant reduction in dermal oedema. NLCs containing linoleic acid presented better anti-inflammatory efficacy by decreasing the production of interleukins in keratinocytes and monocytes. The biomechanical properties of skin revealed an occlusive effect and no hydration power. No signs of skin irritancy in vivo were detected. According to these results, dermal PF-NLCs could be an effective system for the delivery and controlled release of PF, improving its dermal retention, with reduced dermal oedema as a possible effect of this drug.

Comparison of the anti-inflammatory effects of Sinapis alba and Brassica juncea in mouse models of inflammation

BACKGROUND

Sinapis Semen is derived from the dried mature seeds of Sinapis alba L. or Brassica juncea (L.) Czern. et Coss. Traditionally, the seeds from S. alba are called "White Sinapis Semen" while those from B. juncea are called "Yellow Sinapis Semen".

PURPOSE

The present study aimed to compare the chemical composition and the anti-inflammatory effects of 50% aqueous ethanol extracts of the White Sinapis Semen (EWSS) and Yellow Sinapis Semen (EYSS) using both acute (12-O-tetradecanoylphorbol-acetate (TPA)- and arachidonic acid (AA)-induced mouse ear edema) and chronic (multiple applications of croton oil (CO)) inflammatory models.

METHODS

The anti-inflammatory effects of EWSS and EYSS were determined by measuring the ear thickness and myeloperoxidase (MPO) activity. The anti-inflammatory mechanism was explored by measuring the protein and mRNA levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in the ear of the TPA-treated mice.

RESULTS

The results showed that both EWSS and EYSS significantly decreased the ear thickness in both the TPA- and AA-induced acute models, as well as in the CO-induced chronic model. In addition, EWSS and EYSS could markedly inhibit the MPO activity in the ears of TPA-, AA- or CO-treated mice. Moreover, EWSS and EYSS also remarkably inhibited the protein and mRNA levels of TNF-α and IL-6 in the ears of TPA-treated mice. Comparatively, EWSS exerted more potent anti-inflammatory effect than that of EYSS.

CONCLUSION

Our results revealed that both EWSS and EYSS are effective anti-inflammatory agents against acute and chronic inflammatory processes, and EWSS possess more potent anti-inflammatory effect than EYSS. The anti-inflammatory effect of the two herbs may be mediated, at least in part, by suppressing the mRNA expression of a panel of inflammatory mediators including TNF-α, IL-6 and IL-1β.

Identification of compounds from Palicourea rigida leaves with topical anti-inflammatory potential using experimental models

Palicourea rigida Kunth is traditionally used for the treatment of skin diseases, kidney pains and ovarian inflammation. Based on these traditional uses, this study evaluated the topical anti-inflammatory activity of the ethanol extract from P. rigida leaves (EEPR) and identified bioactive compounds. Ear edema was induced in Swiss mice by the topical application of Croton oil, arachidonic acid, phenol and capsaicin. Histopathological analysis and myeloperoxidase and N-acetyl-β-D-glucosaminidase activities were determined. EEPR was characterized by UHPLC-UV-MS HPLC and the isolated compound was identified through ¹H and ¹³C nuclear magnetic resonance and mass fragmentation. Interaction profiles between quercetin 3-O-β-D-glucoside and cyclooxygenase-1 and -2 were established by molecular docking. EEPR significantly inhibited ear edema induced by Croton oil (p < 0.001), arachidonic acid (p < 0.01), phenol (p < 0.001) and capsaicin (p < 0.01 or p < 0.001). Histopathological analysis showed a reduction of edema, inflammatory cell infiltration and vasodilation. Additionally, the myeloperoxidase and N-acetyl-β-D-glucosaminidase activities were decreased (p < 0.001). From spectroscopic data, quercetin 3-O-β-D-glucoside was the identified compound. This compound can to interact with cyclooxygenase-1 and -2 through van der Waals interactions and dipole-dipole and hydrogen bonding's, demonstrating inhibition of these enzymes. The results indicate that EEPR is a source of active compounds with topical anti-inflammatory activity, justifying the traditional use of P. rigida and showing that this species has a therapeutic potential to treat skin inflammatory processes.

Evidence of Bioactive Compounds from Vernonia polyanthes Leaves with Topical Anti-Inflammatory Potential

Vernonia polyanthes Less. (Asteraceae), popularly known as "assa-peixe", is a plant species used in Brazilian traditional medicine for the treatment of cutaneous damage, cicatrization, inflammation, and rheumatism. Based on these ethnopharmacological findings, the current study evaluated the topical anti-inflammatory effects of the hexane (HEVP) and ethyl acetate (EAEVP) extracts from V. polyanthes leaves in experimental models of skin inflammation. Chemical characterization was carried out by HPLC-UV/DAD analysis. Anti-inflammatory activity was evaluated using Croton oil-, arachidonic acid (AA)-, phenol-, ethyl phenylpropiolate (EPP)-, and capsaicin-induced ear edema models in mice. Histopathological evaluation and measurements of myeloperoxidase (MPO) and N-acetyl-β-d-glucosaminidase (NAG) enzymes were also performed. Rutin, luteolin, and apigenin were identified in EAEVP. Topically applied HEVP and EAEVP significantly (p < 0.05, p < 0.01 or p < 0.001) reduced edema induced by five different irritants at the doses tested (0.1, 0.5 and 1.0 mg/ear). Histopathological analysis revealed a reduction of edema, inflammatory cell infiltration, and vasodilation. In addition, the enzymes activity (MPO and NAG) in the ear tissues was reduced by the topical treatment of HEVP and EAEVP (p < 0.05, p < 0.01 or p < 0.001). The results suggest that V. polyanthes leaves are effective against cutaneous damage, which support its traditional use and open up new possibilities for the treatment of skin disorders.

Analgesic and anti-Inflammatory effect of UP3005, a botanical composition Containing two standardized extracts of Uncaria gambir and Morus alba

Background:

Osteoarthritis (OA) is a chronic debilitating degenerative joint disease characterized by cartilage degradation and synovial inflammation exhibited by clinical symptoms such as joint swelling, synovitis, and inflammatory pain. Present day pain relief therapeutics heavily relies on the use of prescription and over the counter nonsteroidal anti-inflammatory drugs as the first line of defense where their long-term usage causes detrimental gastrointestinal and cardiovascular-related side-effects. As a result, the need for evidence based safer and efficacious alternatives from natural sources to overcome the most prominent and disabling symptoms of arthritis is a necessity.

Materials and Methods:

Describe the anti-inflammatory and analgesic effect of UP3005, a composition that contains a standardized blend of two extracts from the leaf of Uncaria gambir and the root bark of Morus alba in carrageenan-induced rat paw edema, abdominal constriction (writhing’s) and ear swelling assays in mouse with oral dose ranges of 100–400 mg/kg.

Results:

In vivo, statistically significant improvement in pain resistance, and suppression of paw edema and ear thickness in animals treated with UP3005 were observed compared with vehicle-treated diseased rats and mice. Ibuprofen was used a reference compound in all the studies. In vitro, enzymatic inhibition activities of UP3005 were determined with IC50 values of 12.4 μg/ml, 39.8 μg/ml and 13.6 μg/ml in cyclooxygenase-2 (COX-1), COX-2 and lipoxygenase (5-LOX) enzyme activity assay, respectively.

Conclusions:

These data suggest that UP3005, analgesic and anti-inflammatory agent of botanical origin with balanced dual COX-LOX inhibition activity, could potentially be used for symptom management of OA.

Anti-inflammatory effects of Bryophyllum pinnatum (Lam.) Oken ethanol extract in acute and chronic cutaneous inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Bryophyllum pinnatum (Lam.) Oken (Crassulaceae), popularly known in Brazil as "folha-da-fortuna", is a plant species used in folk medicine for the external and internal treatment of inflammation, infection, wound, burn, boil, ulcers and gastritis, and several other diseases. The present study aimed to perform the chemical characterization and the evaluation of the topical anti-inflammatory effect of the ethanol extract of Bryophyllum pinnatum leaves (EEBP) in acute and chronic mice ear edema models induced by different irritant agents.

MATERIALS AND METHODS

The EEBP chemical characterization was performed by HPLC-UV DAD. Ear edema on Swiss mice was induced by the topical application of Croton oil (single and multiple applications), arachidonic acid, phenol, capsaicin and ethyl phenylpropiolate (EPP). The topical anti-inflammatory effect of EEBP was evaluated by measuring the ear weight (acute inflammation models) and thickness (chronic inflammation model). Histopathological analyses of ear tissue samples sensitized with Croton oil (single and multiple applications) were also performed.

RESULTS

The flavonoids rutin, quercetin, luteolin and luteolin7-O-β-d-glucoside were detected in EEBP. Topical application of EEBP significantly (P<0.001) inhibited the ear edema induced by Croton oil single application (inhibition of 57%), arachidonic acid (inhibition of 67%), phenol (inhibition of 80%), capsaicin (inhibition of 72%), EPP (inhibition of 75%) and Croton oil multiple application (55% after 9 days). Histopathological analyses confirmed the topical anti-inflammatory effect of EEBP since it was observed reduction of edema, epidermal hyperplasia, inflammatory cells infiltration and vasodilation.

CONCLUSIONS

The results suggest that EEBP is effective as a topical anti-inflammatory agent in acute and chronic inflammatory processes possibly due to inhibition of arachidonic acid pathway, which justify the traditional use of Bryophyllum pinnatum as a remedy for skin disorders.

Cloning of a Gene for a Novel Epithelium-specific Cytosolic Phospholipase A2, cPLA2δ, Induced in Psoriatic Skin

Psoriasis is a common skin disease characterized by hyperplastic regenerative epidermal growth and infiltration of immunocytes. The etiology of psoriasis is unknown, although several genetic and cellular factors have been elucidated. To find new psoriasis-related genes, we have cloned cDNAs that are differentially expressed between normal and psoriatic skins. Among these clones, we have identified a new gene that codes for a new member of the type IV cytosolic phospholipase A(2) (cPLA(2)) family. We refer to this gene as cPLA(2)delta. It encodes a polypeptide of 818 amino acids that has significant homology with known cPLA(2) proteins in the C2 and catalytic domains. The cPLA(2)delta gene was mapped to the 15q13-14 chromosomal locus, near to the locus of the cPLA(2)beta gene, from which it is separated by a physical distance of about 220 kb. To identify the phospholipase A(2) activity of cPLA(2)delta, we transfected COS-7 cells with His-tagged cPLA(2)delta. The cell lysate from these cells had calcium-dependent phospholipase A(2) activity. Northern blot analysis revealed that a cPLA(2)delta transcript of about 4 kb is expressed in stratified squamous epithelia, such as those in skin and cervix, but not in other tissues. In situ hybridization and immunohistochemistry revealed that cPLA(2)delta is expressed strongly in the upper spinous layer of the psoriatic epidermis, expressed weakly and discontinuously in atopic dermatitis and mycosis fungoides, and not detected in the epidermis of normal skin; cPLA(2)alpha is not detected in either normal or psoriatic skin. These results suggest that cPLA(2)delta exhibits a unique distribution pattern compared with that of known cPLA(2) subtypes, and it may play a critical role in inflammation in psoriatic lesions.

Topically applied imiquimod inhibits vascular tumor growth in vivo

Vascular tumors occur in approximately 10% of all infants and may be associated with significant morbidity. Available therapies for vascular tumors, such as systemic corticosteroids, vincristine, and interferon-alpha, may cause toxicity, limiting their use to complicated cases. Using a mouse hemangioendothelioma model, we investigated the efficacy and mechanism of action of imiquimod, a topically applied inducer of cytokines. Application of imiquimod cream, whether initiated at the time of cell inoculation or when tumors became visible, significantly decreased tumor growth and increased animal survival in comparison with control mice. Imiquimod-treated tumors showed decreased tumor cell proliferation, increased tumor apoptosis, and increased expression of tissue inhibitor of matrix metalloproteinase-1 with decreased activity of matrix metalloproteinase-9. The demonstration that local application of imiquimod inhibits vascular tumor enlargement in the mouse vascular tumor model suggests a novel, less toxic means of treating infantile hemangioendotheliomas and perhaps other cutaneous vascular tumors.

Suppression of W256 carcinosarcoma cell apoptosis by arachidonic acid and other polyunsaturated fatty acids

Serum-cultured rat W256 carcinosarcoma cells of the monocytoid origin undergo rapid apoptosis in response to the lipoxygenase inhibitor NDGA (nordihydroguaiaretic acid). Exogenous arachidonic acid (AA), in a time- and dose-dependent fashion, suppressed NDGA-induced W256 cell apoptosis as well as DNA fragmentation, with the maximal effect observed at approximately 25 microM. Mobilization of endogenous AA by calcium ionophore A23187 provided an even stronger and longer-lasting protection against NDGA-caused cell death. The A23187 effect on AA release as well as W256 cell death can be blocked by bromophenacyl bromide, thus suggesting involvement of phospholipase A2 activation. Serum withdrawal similarly caused W256 cells to undergo typical apoptosis, which was not rescued by several growth factors commonly found in serum. However, exogenous AA suppressed serum starvation-induced W256 cell apoptosis and significantly extended cell survival in a dose-dependent manner. Lipoxygenase products, 12(S)- and 15(S)-, but not 5(S)-hydroxyeicosatetraenoic acid (HETE), in a dose-dependent fashion, also prevented both NDGA- and serum-starvation-induced W256 cell apoptosis. AA appears to suppress W256 cell apoptosis via distinct signaling pathway(s) since it does not prevent cell death triggered by several other inducers. Examination of a panel of polyunsaturated fatty acids revealed that alpha-linolenic and linoleic acid can also suppress NDGA-induced W256 cell apoptosis. Our data suggest that AA and other polyunsaturated fatty acids and/or their metabolites may enhance tumor growth not only by promoting cell proliferation but also by suppressing apoptosis.

Protection against ultraviolet-B radiation-induced local and systemic suppression of contact hypersensitivity and edema responses in C3H/HeN mice by green tea polyphenols

Exposure of skin to UV radiation can cause diverse biological effects, including induction of inflammation, alteration in cutaneous immune cells and impairment of contact hypersensitivity (CHS) responses. Our laboratory has demonstrated that oral feeding as well as topical application of a polyphenolic fraction isolated from green tea (GTP) affords protection against the carcinogenic effects of UVB (280-320 nm) radiation. In this study, we investigated whether GTP could protect against UVB-induced immunosuppression and cutaneous inflammatory responses in C3H mice. Immunosuppression was assessed by contact sensitization with 2,4-dinitrofluorobenzene applied to UVB-irradiated skin (local suppression) or to a distant site (systemic suppression), while double skin-fold swelling was used as the measure of UVB-induced inflammation. Topical application of GTP (1-6 mg/animal), 30 min prior to or 30 min after exposure to a single dose of UVB (2 kJ/m2) resulted in significant protection against local (25-90%) and systemic suppression (23-95%) of CHS and inflammation in mouse dorsal skin (70-80%). These protective effects were dependent on the dose of GTP employed; increasing the dose (1-6 mg/animal) resulted in an increased protective effect (25-93%). The protective effects were also dependent on the dose of UVB (2-32 kJ/m2). Among the four major epicatechin derivatives present in GTP, (-)-epigallocatechin-3-gallate, the major constituent in GTP, was found to be the most effective in affording protection against UVB-caused CHS and inflammatory responses. Our study suggests that green tea, specifically polyphenols present therein, may be useful against inflammatory dermatoses and immunosuppression caused by solar radiation.

Enhancement of delayed hypersensitivity inflammatory reactions in guinea pig skin by 12(R)-hydroxy-5,8,14-eicosatrienoic acid

Delayed-type hypersensitivity (DTH) reactions are initiated by sensitized T cells. Their progression is dependent upon the local release of various autacoids, including cytokines and eicosanoids, by T cells, infiltrating inflammatory cells, and resident tissue cells. 12(R)-hydroxy-5,8,14-eicosatrienoic acid [12(R)-HETrE], an eicosanoid produced by skin and cornea, possesses potent proinflammatory properties at picomolar concentrations including vasodilation, increase in membrane permeability, neutrophil chemotaxis, and angiogenesis. Because DTH reactions are associated with many of these same phenomena, we examined the effect of 12(R)-HETrE and related 12-hydroxyeicosanoids on the expression of DTH to purified protein derivative of tuberculin in sensitized guinea pigs. In the absence of purified protein derivative of tuberculin, none of the eicosanoids evoked erythema or edema after intradermal injection at doses up to 100 pmol. When injected together with purified protein derivative of tuberculin, 12(R)-hydroxy-5,8,10,14-eicosatetraenoic acid [12(R)-HETE], but not its enantiomer 12(S)-HETE, significantly inhibited macroscopic expression of delayed reactivity (erythema) only at the highest dose tested, 10 pmol. In contrast, 12(R)-HETrE significantly enhanced expression of DTH at doses between 1 fmol and 1 pmol (50% and 30% increases above control, respectively). Its stereoisomer, 12(S)-HETrE, did not enhance DTH at any tested dose, but was able to block the activity of 12(R)-HETrE when injected simultaneously. Enhancement or inhibition of visible skin responses was not associated with qualitative or quantitative changes in cellular infiltrates at the reaction site. 12(R)-HETrE had no effect on the nonimmunologic inflammatory skin reaction induced by phorbol myristate acetate, suggesting selectivity toward DTH. We conclude that 12(R)-HETrE enhances DTH via a yet to be determined mechanism and that its stereoisomer, 12(S)-HETrE, may be a useful antagonist for studying the inflammatory actions of this eicosanoid.

Changes in tumor interstitial pressure induced by photodynamic therapy

This study has examined the changes in tumor interstitial pressure exhibited during and after photodynamic therapy (PDT). The kinetics of these changes are marked by an initial decrease, followed by a rapid rise in tumor interstitial pressure. We have also employed two inhibitory agents to evaluate the different components of the pressure curve. Specially designed pressure chambers were seeded with chondrosarcoma and implanted subcutaneously in rats. Animals were injected with 0-50 mg/kg Photofrin II (i.v.) 7 days post-implantation and tumors were exposed to 0-540 J/cm2 630 nm 24 h later. Interstitial pressure was monitored via a transducer connected to the implanted chamber. Additional groups of animals were injected with either indomethacin (an inhibitor of thromboxane synthesis) or Ketanserin (a serotonin antagonist) before light treatment. Porphyrin doses of 10 mg/kg and above (135 J/cm2), or light doses of 135 J/cm2 and above (25 mg/kg Photofrin II) were effective in modifying interstitial pressure. Porphyrin doses greater than 25 mg/kg, or light doses greater than 270 J/cm2 produced no further increases in interstitial pressure. Animals given indomethacin (10 mg/kg i.p.) exhibited the initial decrease in pressure during light treatment, but showed no increase past baseline levels. Animals given Ketanserin (10 mg/kg i.p.) demonstrated no decrease in pressure during PDT, but showed the same elevations in pressure as controls. This suggests that two independent mechanisms account for the different components of the pressure curve, and that serotonin release may occur during PDT.

Inflammation of guinea pig dermis. Effects of leukotriene B4 receptor antagonist, SC-41930

Neutrophil (PMNL) infiltration is a prominent feature of human psoriasis. Psoriatic skin lesions contain abnormally high amounts of leukotriene B4 (LTB4), itself a potent PMNL chemoattractant both in vivo and in vitro. SC-41930 (7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxy]-3,4-dihydro-8- propyl-2H-1-benzopyran-2-carboxylic acid), an orally active LTB4 receptor antagonist, was tested topically in models of skin inflammation induced by 200 nmol of the calcium ionophore A23187 or 200 micrograms phorbol-12-myristate-13-acetate (PMA) applied topically to the guinea pig ear as assessed by ear weight, levels of the PMNL marker enzyme myeloperoxidase (MPO), and histological examination (PMA model) at 4 and 18 h respectively. When coapplied topically with A23187 or PMA, SC-41930 significantly inhibited epidermal inflammation with ED50 values of 0.6 and 4 mg, respectively. SC-41930 treatment also was associated with lowered dermal LTB4 levels in both models. The PMA-induced skin inflammation model also was assessed histologically and revealed acanthosis, edema, PMNL infiltration, and rete ridge prominence as long as 96 h after a single application that was completely inhibited by SC-41930 topical coapplication. Furthermore, oral treatment (40 mg/kg) significantly reduced edema and inflammatory cell infiltration in both models. These models possess many of the characteristics of human psoriasis, and agents such as SC-41930 that demonstrate activity in these models may well have therapeutic utility in the treatment of human psoriasis.

Ultraviolet radiation suppresses mouse-ear edema induced by topical application of arachidonic acid

The effect of ultraviolet (UV) radiation on arachidonic acid (AA) cascade was examined using an in vivo model. Mouse ear lobes were painted with 1 mg AA, and the maximum response of ear swelling was measured 1 h after challenge. Arachidonic-acid-induced ear swelling was significantly suppressed by preexposure to topical psoralen plus noninflammatory doses of long-wave UV radiation (PUVA) or middle-wave UV (UVB) radiation. Ultraviolet radiation may interfere with AA pathways to suppress ear swelling since AA-induced ear swelling is considered to be mediated by metabolites derived from exogenous AA. The results may relate to the therapeutic mechanisms of UV radiation in psoriasis in which the eicosanoid cascade is involved.