Bridelia ferruginea Produces Anti-neuroinflammatory Activity through Inhibition of Nuclear Factor-kappa B and p38 MAPK Signalling

Bridelia ferruginea is commonly used in traditional African medicine (TAM) for treating various inflammatory conditions. Extracts from the plant have been shown to exhibit anti-inflammatory property in a number of in vivo models. In this study the influence of B. ferruginea (BFE) on the production of PGE2, nitrite, and proinflammatory cytokines from LPS-stimulated BV-2 microglia was investigated. The effects of BFE on cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expressions were evaluated in LPS-activated rat primary microglia. The roles of NF-κB and MAPK signalling in the actions of BFE were also investigated. BFE (25–200 μg) inhibited the production of PGE2, nitrite, tumour necrosis factor-α (TNFα), and interleukin-6 (IL-6) as well as COX-2 and iNOS protein expressions in LPS-activated microglial cells. Further studies to elucidate the mechanism of anti-inflammatory action of BFE revealed interference with nuclear translocation of NF-κBp65 through mechanisms involving inhibition of IκB degradation. BFE prevented phosphorylation of p38, but not p42/44 or JNK MAPK. It is suggested that Bridelia ferruginea produces anti-inflammatory action through mechanisms involving p38 MAPK and NF-κB signalling

Traditional African Medicine as a source of biologically active substances inhibiting neuroinflammation

Traditional Africa Medicine (TAM) refers to indigenous forms of healing that are practiced all over Africa. One of the most important forms of TAM is the use of herbal extracts for the prevention and treatment of diseases. Neuroinflammation has been shown to be a critical aspect of neurodegenerative disorders, including Alzheimer's disease. Here we show that extracts and bioactive compounds obtained from African plants are able to inhibit neuroinflammatory processes. Our research has shown that cryptolepine, an alkaloid of the West African shrub, Cryptolepis sanguinolenta (Lindl.) Schltr (Apocynaceae) inhibits neuroinflammation in lipopolysaccharide-(LPS)-activated microglia. This alkaloid has been shown to inhibit inflammatory mediator release from activated microglia through mechanisms involving NF-kB and p38 MAPK signalling. Cryptolepine also produced anti-neuroinflammatory actions in IL-1β-stimulated SK-N-SH neuronal cells. Other African plants which have been shown to exhibit varying degrees of inhibition of neuroinflammation are Anacardium occidentale, Bridelia ferruginea, Picralima nitida and Capsicum extract [1], [2]. The results presented in this talk provide a molecular basis for the potential of these African plants in neuroinflammatio

Pomegranate suppresses PGE2 production and COX- 2 expression in IL-1β-stimulated SK-N-SH neuronal cells: implications for Alzheimer’s disease.

Alzheimer's disease (AD) is the most common form of dementia in the elderly and several reports have shown that neuroinflammatory processes contribute to the pathogenesis and progression of AD. Although a number of drugs have been developed for use, they have been shown to produce many side effects with limited therapeutic benefits. Recently, naturally occurring dietary substances have received considerable attention as alternative for AD therapy. Pomegranate (Punica granatum) is consumed globally as a fruit and has been shown to possess powerful antioxidant, anti-carcinogenic and anti-inflammatory properties. In the present study, we have investigated the effects of a lyophilised extract of pomegranate juice (PWE) in IL-1β-stimulated SK-N-SH neuronal cells. Cultured SK-N-SH cells were stimulated with IL-1β in the presence or absence of PWE (25 – 200 µg/ml) for 24h. Results show that PWE produced a dose-dependent suppression of PGE2 production and COX-2 protein expression when compared with IL-1β control. Furthermore, PWE (25 – 200 µg/ml) dose-dependently inhibited IL-1β-induced nuclear translocation of the NF-κBp65 subunit and IκB phosphorylation in SK-N-SH cells. Consistent with its anti-neuroinflammatory actions, PWE inhibited IL-1β-induced Aβ1 – 42 generation and expression of β-secretase (BACE-1). Taken together, it is suggested that pomegranate fruit may be useful in preventing the development and progression of A

Inhibition of TNF-α synthesis in LPS-stimulated primary human monocytes by Harpagophytum extract SteiHap 69

Harpagophytum procumbens (Devil\u27s Claw) is often used in the supportive treatment of inflammatory and degenerative diseases of the skeletal system. Here we studied the anti-inflammatory properties of the Harpagophytum extract SteiHap 69 (Steiner Harpagophytum procumbens extract 69) on primary human monocytes, a useful model of peripheral inflammation. After eliminating lipopolysaccharides of bacterial origin, SteiHap 69 prevented the LPS-induced synthesis of tumour necrosis factor alpha (TNFα) in stimulated primary human monocytes in a dose-dependent manner. Harpagide and harpagoside had no effect on LPS-induced TNFα-release. Our data provides evidence that the Harpagophytum extract SteiHap 69 has anti-inflammatory properties. Further studies are required in order to elucidate the molecular mechanism of Devil\u27s claw anti-inflammatory effects

Effects of Cryptolepis sanguinoleta root extract in lipopolysaccharide – stimulated human primary monocytes

Cryptolepis sanguinoleta is a shrub used in West Africa for the treatment of fevers, and inflammatory conditions. In the present study the effect of the crude methanolic root extract of C. sanguinoleta on prostaglandin E2 (PGE2) release from LPS-stimulated human primary monocytes was investigated using an enzyme immunoassay. The effects of the extract on COX -2, I kappa Bα and p38 MAP Kinase proteins were also investigated. The extract (2.5-10µg/ml) produced a dose-dependent inhibition of LPS - induced PGE2 release in human primary monocytes. Western blot experiments showed that the extract inhibited LPS - induced COX -2 expression, as well as LPS - induced activation of p38 MAP kinase. However, the extract did not prevent LPS-induced I kappa Bα degradation in these cells. This study has therefore established in vitro potential anti - inflammatory properties of the root of C. sanguinoleta in LPS - stimulated human primary monocytes. It is suggested that the inhibition of LPS - induced PGE production in these cells by the root extract of C. sanguinoleta is mediated through inhibition of COX -2 protein. We further postulate that the observed effects may be dependent on the inhibition of p38 MAP kinase activation

Mechanisms of Anti-inflammatory Property of Anacardium occidentale Stem Bark: Inhibition of NF-kappaB and MAPK Signaling in the Microglia

Ethnopharmacological relevance Anacardium occidentale is used in traditional African medicine for the treatment of arthritis, fever, aches, pains, and inflammation of the extremities. Aim of the study In this study, we investigated the molecular mechanisms responsible for anti-inflammatory effects of a stem bark extract of A. occidentale (ANE) in LPS-stimulated microglia. Materials and methods Nitric oxide (NO), prostaglandin E2 and cytokine (TNFα and IL-6) production were evaluated in supernatants from LPS-stimulated BV-2 cells. Cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and microsomal prostaglandin E2 synthase (mPGES-1) protein expressions in rat primary microglia were measured using western blot. The effects of ANE on NF-κB activation and nuclear translocation were evaluated in the luciferase reporter gene assay and ELISA, while ability of ANE to influence IκB phosphorylation was determined using ELISA specific for phospho-IκB. The involvement of MAPK phosphorylation in the anti-inflammatory actions of ANE was evaluated using specific ELISA for phospho-p38, phospho-p42/44 and phospho-JNK. The MTT assay was used to determine the effect of ANE on BV-2 microglia viability. Results ANE (25–100 μg/ml) produced significant (p<0.05) reduction in the production of NO, PGE2, TNFα and IL-6 in BV-2 microglia stimulated with LPS for 24 h. Pre-treatment with ANE caused a significant (p<0.05) inhibition of COX-2, iNOS and mPGES-1 protein expressions in the rat primary microglia. Further experiments showed that ANE inhibited COX-2 and iNOS protein expression via IκB-mediated nuclear translocation and transactivation of NF-κB. Our studies also revealed that ANE produced significant (p<0.05) and dose-dependent inhibition of p38, p42/44 and JNK MAPK phosphorylation in LPS-activated BV-2 microglia. Conclusions We conclude that ANE has an anti-inflammatory property related to inhibition of inflammation-associated cytokine production as well as iNOS and COX-2 gene expression by blocking NF-κB and MAPK pathways in the microglia. It is also suggested that mPGES-1 inhibition contributes to the effect of ANE on PGE2 production in the microglia

Inhibition of Neuroinflammation in LPS-Activated Microglia by Cryptolepine.

noCryptolepine, an indoloquinoline alkaloid in Cryptolepis sanguinolenta, has anti-inflammatory property. In this study, we aimed to evaluate the effects of cryptolepine on lipopolysaccharide (LPS)- induced neuroinflammation in rat microglia and its potential mechanisms. Microglial activation was induced by stimulation with LPS, and the effects of cryptolepine pretreatment on microglial activation and production of proinflammatory mediators, PGE2/COX-2, microsomal prostaglandin E2 synthase and nitric oxide/iNOS were investigated. We further elucidated the role of Nuclear Factor-kappa B (NF-κB) and the mitogen-activated protein kinases in the antiinflammatory actions of cryptolepine in LPS-stimulated microglia. Our results showed that cryptolepine significantly inhibited LPS-induced production of tumour necrosis factor-alpha (TNFα), interleukin-6 (IL-6), interleukin-1beta (IL-1β), nitric oxide, and PGE2. Protein and mRNA levels of COX-2 and iNOS were also attenuated by cryptolepine. Further experiments on intracellular signalling mechanisms show that IκB-independent inhibition of NF-κB nuclear translocation contributes to the anti-neuroinflammatory actions of cryptolepine. Results also show that cryptolepine inhibited LPS-induced p38 and MAPKAPK2 phosphorylation in the microglia. Cell viability experiments revealed that cryptolepine (2.5 and 5 μM) did not produce cytotoxicity in microglia. Taken together, our results suggest that cryptolepine inhibits LPS-induced microglial inflammation by partial targeting of NF-κB signalling and attenuation of p38/MAPKAPK2

Interleukin-1 beta uses common and distinct signaling pathways for induction of the interleukin-6 and tumor necrosis factor alpha genes in the human astrocytoma cell line U373

Lieb K, Kaltschmidt C, Kaltschmidt B, et al. Interleukin-1 beta uses common and distinct signaling pathways for induction of the interleukin-6 and tumor necrosis factor alpha genes in the human astrocytoma cell line U373. J. Neurochem. 1996;66(4):1496-1503

A minocycline derivative reduces nerve injury-induced allodynia, LPS-induced prostaglandin E2 microglial production and signaling via toll-like receptors 2 and 4

Many studies have shown that minocycline, an antibacterial tetracycline, suppresses experimental pain. While minocycline's positive effects on pain resolution suggest that clinical use of such drugs may prove beneficial, minocycline's antibiotic actions and divalent cation (Ca2+; Mg2+) chelating effects detract from its potential utility. Thus, we tested the antiallodynic effect induced by a non-antibacterial, non-chelating minocycline derivative in a model of neuropathic pain and performed an initial investigation of its anti-inflammatory effects in vitro. Intraperitoneal minocycline (100mg/kg) and 12S-hydroxy-1,12-pyrazolinominocycline (PMIN; 23.75mg/kg, 47.50mg/kg or 95.00mg/kg) reduce the mechanical allodynia induced by chronic constriction injury of mouse sciatic nerve. PMIN reduces the LPS-induced production of PGE2 by primary microglial cell cultures. Human embryonic kidney cells were transfected to express human toll-like receptors 2 and 4, and the signaling via both receptors stimulated with PAM3CSK4 or LPS (respectively) was affected either by minocycline or PMIN. Importantly, these treatments did not affect the cell viability, as assessed by MTT test. Altogether, these results reinforce the evidence that the anti-inflammatory and experimental pain suppressive effects induced by tetracyclines are neither necessarily linked to antibacterial nor to Ca2+ chelating activities. This study supports the evaluation of the potential usefulness of PMIN in the management of neuropathic pain, as its lack of antibacterial and Ca2+ chelating activities might confer greater safety over conventional tetracyclines. \ua9 2013 Elsevier Ireland Ltd.Peer reviewed: YesNRC publication: Ye