Development of a p38δ mitogen activated protein kinase ELISA assay for the quantitative determination of inhibitor activity

Antiulcerogenic Potential of the Ethanolic Extract of Ceiba speciosa (A. St.-Hil.) Ravenna Evaluated by In Vitro and In Vivo Studies

Gastrointestinal diseases, such as peptic ulcers, are caused by a damage in the gastric mucosa provoked by several factors. This stomach injury is regulated by many inflammatory mediators and is commonly treated with proton-pump inhibitors, histamine H2 receptor blockers and antacids. However, various medicinal plants have demonstrated positive effects on gastric ulcer treatment, including plants of the Ceiba genus. The aim of this study was to evaluate the antiulcer and anti-inflammatory activities of the stem bark ethanolic extract of Ceiba speciosa (A. St.-Hil.) Ravenna. We performed a preliminary quantification of phenolic compounds by high-performance liquid chromatography-diode array detection (HPLC-DAD), followed by the prospection of other chemical groups through nuclear magnetic resonance (NMR) spectroscopy. A set of in vitro assays was used to evaluate the extract potential regarding its antioxidant activity (DPPH: 19.83 ± 0.34 µg/mL; TPC: 307.20 ± 6.20 mg GAE/g of extract), effects on cell viability and on the release of TNF-α in whole human blood. Additionally, in vivo assays were performed to evaluate the leukocyte accumulation and total protein quantification in carrageenan-induced air pouch, as well as the antiulcerogenic effect of the extract on an ethanol-induced ulcer in rats. The extract contains flavonoids and phenolic compounds, as well as sugars and quinic acid derivatives exhibiting potent antioxidant activity and low toxicity. The extract reduced the release of TNF-α in human blood and inhibited the activity of p38α (1.66 µg/mL), JAK3 (5.25 µg/mL), and JNK3 (8.34 µg/mL). Moreover, it reduced the leukocyte recruitment on the pouch exudate and the formation of edema, reverting the effects caused by carrageenan. The extract presented a significant prevention of ulcer formation and a higher reduction than the reference drug, Omeprazole. Therefore, C. speciosa extract has demonstrated relevant therapeutic potential for the treatment of gastric diseases, deserving the continuation of further studies to unveil the mechanisms of action of plant bioactive ingredients.

Antimicrobial and antileukemic effects: in vitro activity of Calyptranthes grandifolia aqueous leaf extract

Natural products are still a promising source of bioactive molecules. Food and Drug Administration data showed that approximately 49% of the approved molecules originate naturally or chemically-resemble these substances, of which more than 70% are being used in anticancer therapy. It is noteworthy that at present there are no scientific studies to prove the effectiveness and safety of a number of plants used in folk medicine such as in the case of Calyptranthes grandifolia O. Berg (Myrtaceae) originally from South America. The aim of the present study was to determine the biological potential and toxicological effects of the aqueous leaf extract of C. grandifolia. The main detected phytoconstituents were condensed tannins and flavonoids and a high quantity of polyphenols. Regarding the antimicrobial potential, the extract exerted inhibitory activity against Pseudomonas aeruginosa. The results also revealed the extract induced DNA damage in a concentration-dependent manner in RAW 264.7 cells. In addition, C. grandifolia produced cytotoxicity in leukemia cell lines (HL60 and Kasumi-1) without affecting isolated human lymphocytes but significantly inhibited JAK3 and p38α enzyme activity. Taken together, these findings add important information on the biological and toxicological effects of C. grandifolia, indicating that aqueous extract may be a source of natural antimicrobial and antileukemic constituents.

Antinociceptive, anti-inflammatory and gastroprotective effects of a hydroalcoholic extract from the leaves of Eugenia punicifolia (Kunth) DC. in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

An ethnopharmacological survey indicated that leaves from Eugenia punicifolia (Kunth) DC. (Myrtaceae) are popularly used as a natural therapeutic agent to treat pain and inflammation.

AIM OF THE STUDY

The overall objective of the present study was to evaluate the antinociceptive, anti-inflammatory and gastroprotective activities of a hydroalcoholic extract of leaves from Eugenia punicifolia (HEEP) in rodents.

MATERIAL AND METHODS

The antinociceptive effects of HEEP were evaluated in mice after oral administration in chemical (formalin and glutamate) and thermal (hot-plate) tests. We evaluated the involvement of the glutamatergic, opioidergic and nitrergic pathways in the antinociception of HEEP and the effect of HEEP on the inhibition of p38α MAPK. The anti-inflammatory effect of HEEP was evaluated in mice and rats using xylene-induced ear edema and carrageenan-induced paw edema, respectively. Furthermore, the gastroprotective effect of HEEP was evaluated in rats with acute gastric lesions induced by ethanol or indomethacin. Finally, we performed a phytochemical analysis of HEEP.

RESULTS

The oral administration of HEEP (125, 250 and 500mg/kg, p.o.) significantly inhibited the neurogenic and inflammatory phases of formalin-induced licking, and HEEP (250mg/kg, p.o.) also significantly inhibited the nociception caused by glutamate. The antinociceptive effects of HEEP were significantly reversed by l-arginine (500mg/kg, i.p.) but not by naloxone (1mg/kg, i.p.) in the formalin test. HEEP did not affect animal motor performance in the rotarod model. In addition, HEEP also increased the paw withdraw latency in the hot-plate test. HEEP significantly inhibited ear edema induced by xylene (64%) and paw edema induced by carrageenan (50%) compared to the control group. Furthermore, HEEP (3-30mg/mL) also inhibited the phosphorylation of p38α MAPK by approximately 90%. In addition, HEEP (125, 250 and 500mg/kg, p.o.) protected the rats against ethanol (88.4-99.8%) and indomethacin (53-72.3%) and increased the mucus levels of the gastric mucosa without producing an antisecretory effect. The phytochemical profile of HEEP obtained using HPLC-PDA showed secondary metabolites already reported for the genus, mostly flavonoids, gallotannins and proanthocyanidins.

CONCLUSIONS

These data show for the first time that HEEP has significant antinociceptive and anti-inflammatory effects, which appear to be related to the inhibition of the glutamatergic system, the synthesis of nitric oxide and the inhibition of the phosphorylation of p38α MAPK. HEEP also has interesting gastroprotective effects related to the maintenance of protective factors, such as mucus production. These results support the use of Eugenia punicifolia in popular medicine and demonstrate that this plant has therapeutic potential for the development of phytomedicines with antinociceptive, anti-inflammatory and gastroprotective properties.

Entada africana fraction CH₂Cl₂/MEOH 5% inhibits inducible nitric oxide synthase and pro-inflammatory cytokines gene expression induced by lipopolysaccharide in microglia

Background

Inflammatory response in the CNS mediated by microglia cells play an important role in host defense and is implicated in the pathology of neurodegenerative diseases. We investigated the capacity of Entada africana to protect microglia from inflammatory insults by exploring the effect of the CH₂Cl₂/MEOH 5% fraction (Ea5) on pro-inflammatory cytokines mRNA expression. Finally, we studied the effect of Ea5 on the inhibition of p38 MAPK Kinase. The results were compared to those obtained with Baicalin, a well reported anti-inflammatory flavonoid.

Methods

Barks from E. africana were harvested in 2010, in the west region of Cameroon. A crude extract was prepared using CH₂Cl₂/MEOH 1:1 V/V. The crude extract obtained was further fractionated by flash chromatography. A mouse microglia cell line (N9) was stimulated by LPS with or without different concentrations of Baicalin and Ea5. The release of NO was evaluated using the Griess method. The expression of pro-inflammatory cytokines mRNA (TNFα, IL-1β, IL-6) and iNOS/NO were measured by RT- PCR. The inhibition of p38 MAPK Kinase was assessed using ELISA.

Results

We found that Ea5, as well as Baicalin inhibited LPS-induced NO production in a dose dependent manner. Ea5 was most active in term of NO inhibition (87.07%), in comparison to Baicalin (70.85%). The expression of TNFα, IL-1β, IL-6 and iNOS was strongly suppressed by Ea5 in microglia. Ea5 also inhibited the activity of p38MAPK Kinase, up to 30% for the concentrations tested, whereas a prominent inhibition was obtained with Baicalin.

Conclusion

These results suggest that E. africana may contain promising compounds useful for the treatment of diseases cause by over-activation of microglia such as Alzheimer disease and other neurological diseases.

A fraction of stem bark extract of Entada africana suppresses lipopolysaccharide-induced inflammation in RAW 264.7 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Entada africana is a plant used in African traditional medicine for the treatment of stomachache, fever, liver related diseases, wound healing, cataract and dysentery.

AIMS OF THE STUDY

This study aimed at evaluating the anti-inflammatory activity of fractions of the stem bark extract of the plant using lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages model.

MATERIALS AND METHODS

The crude extract was prepared using the mixture CH2Cl2/MeOH (1:1, v/v) and fractionated by flash chromatography using solvents of increasing polarity to obtain five different fractions. The effects of the fractions on the cells viability were studied by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and their inhibitory activity against LPS-induced nitric oxide (NO) production screened by Griess test. The most active fraction was further investigated for its effects on reactive oxygen species (ROS) production using flux cytometry, the expression of inducible nitric oxide synthase (iNOS), pro-and anti-inflammatory cytokines (IL1β, TNFα, IL6, IL10 and IL13) by RT-PCR, and the activity of the enzyme p38 MAPK kinase by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The fractions presented no significant effect on the viability of macrophages at 100 μg/ml after 24h incubation. The CH2Cl2/MeOH 5% (Ea5) fraction was found to be the most potent in inhibiting NO production with a half inhibition concentration (IC50)=18.36 μg/ml, and showed the highest inhibition percentage (89.068%) in comparison with Baicalin (63.34%), an external standard at 50 μg/ml. Ea5, as well as Baicalin significantly (P<0.05) inhibited the expression of TNFα, IL6 and IL1β mRNA, attenuated mRNA expression of inducible NO synthase in a concentration-dependent manner, stimulated the expression of anti-inflammatory cytokines (IL10 and IL13), and showed a 30% inhibition of the activity of p38 MAPK kinase.

CONCLUSION

The results of the present study indicate that the fraction Ea5 of Entada africana possesses most potent in vitro anti-inflammatory activity and may contain compounds useful as a therapeutic agent in the treatment of inflammatory related diseases cause by over-activation of macrophages.