This study investigated the antinociceptive effects of zerumbone in chemical behavioural models of nociception in mice. Zerumbone given through intraperitoneal route (i.p.) produced dose-related antinociception when assessed on acetic acid-induced abdominal writhing test in mice. In addition, the i.p. administration of zerumbone exhibited significant inhibition of the neurogenic pain induced by intraplantar (i.pl.) injection of capsaicin and bradykinin. Likewise, zerumbone given by i.p. route reduced the nociception produced by i.pl. injection of glutamate and phorbol myristate acetate (PMA). The antinociception caused by zerumbone in the acetic acid test was significantly attenuated by i.p. pre-treatment of mice with l-arginine (nitric oxide precursor) and glibenclamide (ATP-sensitive K(+) channel inhibitor). However, the antinociception of zerumbone was enhanced by methylene blue (non-specific gyanylyl cyclase inhibitor). Together, these results indicate that zerumbone produces pronounced antinociception against chemical models of nociception in mice. It also strongly suggests that the l-arginine-nitric oxide-cGMP-PKC-K(+) ATP channel pathways, the TRPV1 and kinin B2 receptors play an important role in the zerumbone-induced antinociception.
Zerumbone, a bioactive sesquiterpene isolated from Zingiber zerumbet (Smith), has shown to exert antiallodynic and antihyperalgesic effects in neuropathic pain mice model in our recent study. The mechanism through which zerumbone alleviates neuropathic pain has yet to be elucidated. Thus, this study aimed to determine whether the serotonergic system, part of the descending pain modulation pathway, contributes to the antineuropathic effect of zerumbone. Participation of the serotonergic system in zerumbone-induced antiallodynia and antihyperalgesia was assessed using Dynamic Plantar Aesthesiometer von Frey test and Hargreaves plantar test respectively in chronic-constriction injury mice model. Administration of ρ-chlorophenylalanine (PCPA, 100mg/kg, i.p.) for four consecutive days to deplete serotonin (5-HT) prior to zerumbone administration blocked the antiallodynic and antihyperalgesic effects of zerumbone. Further investigation with 5-HT receptor antagonists methiothepin (5-HT1/6/7 receptor antagonist, 0.1mg/kg), WAY-100635 (5-HT1A receptor antagonist, 1mg/kg), isamoltane (5-HT1B receptor antagonist, 2.5mg/kg), ketanserin (5-HT2A receptor antagonist, 0.3mg/kg) and ondansetron (5-HT3 receptor antagonist, 0.5mg/kg) managed to significantly attenuate antiallodynic and antihyperalgesic effects of zerumbone (10mg/kg). These findings demonstrate that zerumbone alleviates mechanical allodynia and thermal hyperalgesia through the descending serotonergic system via 5-HT receptors 1A, 1B, 2A, 3, 6 and 7 in chronic constriction injury neuropathic pain mice.
The present study investigates the involvement of the l-arginine-Nitric Oxide-cGMP-K⁺ ATP pathways responsible for the action of anti-allodynic and antihyperalgesic activities of zerumbone in chronic constriction injury (CCI) induced neuropathic pain in mice. The role of l-arginine-NO-cGMP-K⁺ was assessed by the von Frey and the Randall-Selitto tests. Both allodynia and hyperalgesia assessments were carried out on the 14th day post CCI, 30 min after treatments were given for each respective pathway. Anti-allodynic and antihyperalgesic effects of zerumbone (10 mg/kg, i.p) were significantly reversed by the pre-treatment of l-arginine (10 mg/kg), 1H [1,2,4]Oxadiazole[4,3a]quinoxalin-1-one (ODQ), a soluble guanosyl cyclase blocker (2 mg/kg i.p.) and glibenclamide (ATP-sensitive potassium channel blocker) (10 mg/kg i.p.) (p < 0.05). Taken together, these results indicate that systemic administration of zerumbone produces significant anti-allodynic and antihyperalgesic activities in neuropathic pain in mice possibly due to involvement of the l-arginine-NO-cGMP-PKG-K⁺ ATP channel pathways in CCI model.
A series of preliminary studies was carried out to evaluate the antinociceptive (pain relief) activity of the aqueous extract of Corchorus olitorius L. leaves (COAE) and to determine the influence of temperature and opioid receptors on COAE activity using the abdominal constriction and hot plate tests in mice. COAE, at concentrations of 10, 25, 50, 75, and 100%, showed both peripheral and central antinociception that are non-concentration- and concentration-dependent respectively. The peripheral activity was clearly observed at a concentration of 25% and diminished at a concentration of 100%, while the central activity was observed at all the concentrations of COAE used. Furthermore, the insignificant results obtained indicated that this peripheral activity (at concentrations of 25 and 50%) was comparable to that of morphine (0.8 mg/kg). Pre-heating COAE at a temperature of 80 degrees C and 100 degrees C, or 60 degrees C and 80 degrees C was found to enhance its peripheral and central antinociception respectively. Pre-treatment with naloxone (10 mg/kg), a general opioid receptor antagonist, for 5 min, followed by COAE, was found to completely block its peripheral, but not central, antinociceptive activity. Based on this observation, we conclude that the antinociceptive activity exhibited by C. olitorius is enhanced by the increase in temperature and may be mediated peripherally, but not centrally, at least in part, via an opioid receptor.
We previously showed that 2,6-bis-(4-hydroxyl-3-methoxybenzylidine)cyclohexanone (BHMC), suppressed the synthesis of various proinflammatory mediators. In this study we explain the mechanism of action of BHMC in lipopolysaccharide (LPS)-induced U937 monocytes and further show that BHMC prevents lethality of CLP-induced sepsis. BHMC showed dose-dependent inhibitory effects on p38, JNK and ERK 1/2 activity as determined by inhibition of phosphorylation of downstream transcription factors ATF-2, c-Jun and Elk-1 respectively. Inhibition of these transcription factors subsequently caused total abolishment of AP-1-DNA binding. BHMC inhibited p65 NF-κB nuclear translocation and DNA binding of p65 NF-κB only at the highest concentration used (12.5μM) but failed to alter phosphorylation of JNK, ERK1/2 and STAT-1. Since the inhibition of p38 activity was more pronounced we evaluated the possibility that BHMC may bind to p38. Molecular docking experiments confirmed that BHMC fits well in the highly conserved hydrophobic pocket of p38 MAP kinase. We also show that BHMC was able to improve survival from lethal sepsis in a murine caecal-ligation and puncture (CLP) model.
To determine the involvement of nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway in aqueous supernatant of haruan (Channa striatus) fillet (ASH) antinociception using the acetic acid-induced abdominal constriction test.
Crude extract of ChE from the liver of Puntius javanicus was purified using procainamide-sepharyl 6B. S-Butyrylthiocholine iodide (BTC) was selected as the specific synthetic substrate for this assay with the highest maximal velocity and lowest biomolecular constant at 53.49 µmole/min/mg and 0.23 mM, respectively, with catalytic efficiency ratio of 0.23. The optimum parameter was obtained at pH 7.5 and optimal temperature in the range of 25 to 30°C. The effect of different storage condition was assessed where ChE activity was significantly decreased after 9 days of storage at room temperature. However, ChE activity showed no significant difference when stored at 4.0, 0, and -25°C for 15 days. Screening of heavy metals shows that chromium, copper, and mercury strongly inhibited P. javanicus ChE by lowering the activity below 50%, while several pairwise combination of metal ions exhibited synergistic inhibiting effects on the enzyme which is greater than single exposure especially chromium, copper, and mercury. The results showed that P. javanicus ChE has the potential to be used as a biosensor for the detection of metal ions.
The present study was carried out to investigate on the possible involvement of L-arginine/nitric oxide/cyclic guanosine monophosphate (L-arginine/NO/cGMP) pathway in the aqueous extract of Muntingia calabura (AEMC) leaves antinociception in mice assessed by abdominal constriction test. The AEMC, obtained by soaking the dried leaves in distilled water (DH(2)O) (1 : 2; w/v) for 24 h, was prepared in concentrations of 10%, 50% and 100% that were approximately equivalent to doses of 27, 135 and 270 mg/kg, and administered subcutaneously (s.c.) 5 min after pre-treatment (s.c.) of mice with DH(2)O, L-arginine (20 mg/kg), N(G)-monomethyl-L-arginine acetate (L-NMMA; 20 mg/kg), N(G)-nitro-L-arginine methyl esters (L-NAME; 20 mg/kg), methylene blue (MB) (20 mg/kg), respectively. The AEMC was found to exhibit a concentration-dependent antinociception after pre-challenge with DH(2)O. Interestingly, pre-treatment with L-arginine was found to block significantly (P < 0.05) the AEMC antinociception but only at the highest concentration (100%) of AEMC used. On the other hand, pre-treatment with L-NAME was found to significantly (P < 0.05) enhance the low concentration but inhibit the high concentration AEMC antinociception. MB was found to significantly (P < 0.05) enhance AEMC antinociception at all concentrations used. Except for the higher concentration of AEMC used, co-treatment with L-NAME was found to insignificantly and significantly (P < 0.05) reverse the L-arginine effect when given alone or with low concentration AEMC, respectively. In addition, co-treatment with MB significantly (P < 0.05) reversed the L-arginine effect when given alone or with 10% concentration AEMC but failed to affect the activity of the rest of concentrations used. As a conclusion, this study has demonstrated the involvement of L-arginine/NO/cGMP pathway in AEMC antinociception.
The present study was carried out to investigate the antinociceptive activity of the aqueous extract of Muntingia calabura (MCAE) leaves and to determine the effect of temperature and the involvement of the opioid receptor on the said activity using the abdominal constriction test (ACT) and hot-plate test (HPT) in mice.
Alveolar epithelial barrier dysfunction contributes to lung edema and can lead to acute lung injury (ALI). The features include increased epithelial permeability, upregulation of inflammatory mediators and downregulation of junctional complex molecules; these changes are often induced by inflammation. tHGA is an acetophenone analogue with therapeutic potential in asthma. Its therapeutic potential in ALI is presently unknown. Herein, the effects of tHGA on epithelial barrier dysfunction were determined in TNF-α-induced human alveolar epithelial cells. The anti-inflammatory properties of tHGA were assessed by monocyte adhesion assay and analysis of MCP-1 and ICAM-1 expression. The epithelial barrier function was assessed by paracellular permeability and transepithelial electrical resistance (TEER) assays, and analysis of junctional complex molecules expression. To elucidate the mechanism of action, the effects of tHGA on the NF-κB and MAPK pathways were determined. Gene and protein expression were analyzed by RT-PCR and Western blotting or ELISA, respectively. tHGA suppressed leukocyte adhesion to TNF-α-induced epithelium and reduced MCP-1 and ICAM-1 gene expression and secretion. tHGA also increased TEER readings, reduced epithelial permeability and enhanced expression of junctional complex molecules (zona occludens-1, occludin and E-cadherin) in TNF-α-induced cells. Correspondingly, the NF-κB, ERK and p38 MAPK pathways were also inhibited by tHGA. These findings suggest that tHGA is able to preserve alveolar epithelial barrier function in response to acute inflammation, via its anti-inflammatory activity and stabilization of epithelial barrier integrity, mediated by NF-κB, ERK and p38 MAPK signaling.
We have investigated the antinociceptive activity of zerumbone (1), a natural cyclic sesquiterpene isolated from Zingiber zerumbet Smith, in acetic acid-induced abdominal writhing test and hot plate test in mice. 1 given by intraperitoneal route produced significant dose-dependent antinociceptive effect in all the test models used. In addition, the antinociceptive effect of 1 in the hot plate test was reversed by the non-selective opioid receptor antagonist naloxone, suggesting that the opioid system is involved in its analgesic mechanism of action.
Nonsteroidal anti-inflammatory drugs (NSAIDs) have been widely used for the treatment of inflammation. However, despite their effectiveness, most NSAIDs cause various side effects that negatively affect the management of inflammation and, in part, pain. Thus, there is a need to search for new anti-inflammatory agents with few, or no, side effects. Natural products of plant, animal, or microorganism origin have been good sources of new bioactive compounds. The present study was carried out to evaluate the acute and chronic anti-inflammatory activities of the essential oil of the rhizomes of Zingiber zerumbet (Zingiberaceae) using the carrageenan-induced paw edema and cotton pellet-induced granuloma tests, respectively. The effect of the essential oil on inflammatory- and noninflammatory-mediated pain was also assessed using the formalin test. Essential oil of Z. zerumbet, at doses of 30, 100, and 300 mg/kg, was administered intraperitoneally to rats. The substance exhibited significant anti-inflammatory activity both in acute and chronic animal models. The essential oil also inhibited inflammatory- and noninflammatory-mediated pain when assessed using the formalin test. In conclusion, the essential oil of Z. zerumbet possessed anti-inflammatory activity, in addition to its antinociceptive activity, which may explain its traditional uses to treat inflammatory-related ailments.
The possible mechanisms of action in the antinociceptive activity induced by systemic administration (intraperitoneal, i.p.) of flavokawin B (FKB) were analysed using chemical models of nociception in mice. It was demonstrated that i.p. administration of FKB to the mice at 0.3, 1.0, 3.0 and 10 mg/kg produced significant dose-related reduction in the number of abdominal constrictions. The antinociception induced by FKB in the acetic acid test was significantly attenuated by i.p. pre-treatment of mice with L-arginine, the substrate for nitric oxide synthase or glibenclamide, the ATP-sensitive K(+) channel inhibitor, but was enhanced by methylene blue, the non-specific guanylyl cyclase inhibitor. FKB also produced dose-dependent inhibition of licking response caused by intraplantar injection of phorbol 12-myristate 13-acetate, a protein kinase C activator (PKC). Together, these data indicate that the NO/cyclic guanosine monophosphate/PKC/ATP-sensitive K(+) channel pathway possibly participated in the antinociceptive action induced by FKB.
The term Java tea refers to the decoction of Orthosiphon stamineus (OS) Benth (Lamiaceae) leaves, which are widely consumed by the people in Europe and South East Asian countries. The OS leaves are known for their use in traditional medicinal systems as a prophylactic and curative agent for urinary stone, diabetes, and hypertension and also as a diuretic agent. The present study was aimed at evaluating its possible toxicity. Herein, the major phytochemical constituents of microwave dried OS leaf, which is the common drying process for tea sachets in the market, were also identified. The acute oral toxicity test of aqueous, 50% aqueous ethanolic, and ethanolic extracts of OS was performed at a dose of 5000 mg/Kg body weight of Sprague-Dawley rats. During the 14-day study, the animals were observed for any mortality, behavioral, motor-neuronal abnormalities, body weight, and feed-water consumption pattern. The hematological and serum biochemical parameters to assess the kidney and liver functions were carried out, along with the histological analysis of these organs. It was found that all microwave dried OS leaf extracts did not cause any toxic effects or mortality at the administered dose. No abnormality was noticed in all selected parameters in rats of both sexes as compared with their respective control groups. Thus, the possible oral lethal dose for microwave dried Java tea leaves is more than 5000 mg/Kg body weight.
Previous studies have shown that systemic administration of 6'-hydroxy-2',4'-dimethoxychalcone (flavokawin B, FKB) exerts significant peripheral and central antinociceptive effects in laboratory animals. However, the mechanisms underlying these peripheral and central antinociceptive effects have yet to be elucidated. Therefore, the objective of the present study was to evaluate the participation of nitric oxide (NO)/cyclic guanosine monophosphate (cGMP)/potassium (K+) channels pathway in the peripheral antinociception induced by FKB. It was demonstrated that intraplantar (i.pl.) administration of FKB (150, 250, 375 and 500 µg/paw) resulted in dose-dependent peripheral antinociception against mechanical hyperalgesia in carrageenan-induced hyperalgesia test model in rats. The possibility of FKB having either a central or a systemic effect was excluded since administration of FKB into the right paw did not elicit antinociception in the contralateral paw. Furthermore, peripheral antinociception induced by FKB (500 µg/paw) was significantly reduced when L-arginine (25 µg/paw, i.pl.), Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 50 µg/paw, i.pl.), glibenclamide (300 µg/paw, i.pl.), tetraethylammonium (300 µg/paw, i.pl.) and charybdotoxin (3 µg/paw, i.pl.) were injected before treatment. Taken together, our present data suggest that FKB elicits peripheral antinociception when assessed in the mechanical hyperalgesia induced by carrageenan. In addition, it was also demonstrated that this effect was mediated through interaction of the NO/cGMP/K+ channels signaling pathway.
Itraconazole and fluconazole are potent wide spectrum antifungal drugs. Both of these drugs induce hepatotoxicity clinically. The mechanism underlying the hepatotoxicity is unknown. The purpose of this study was to investigate the role of phenobarbital (PB), an inducer of cytochrome P450 (CYP), and SKF 525A, an inhibitor of CYP, in the mechanism of hepatotoxicity induced by these two drugs in vivo. Rats were pretreated with PB (75 mg/kg for 4 days) prior to itraconazole or fluconazole dosing (20 and 200 mg/kg for 4 days). In the inhibition study, for 4 consecutive days, rats were pretreated with SKF 525A (50 mg/kg) or saline followed by itraconazole or fluconazole (20 and 200 mg/kg) Dose-dependent increases in plasma alanine aminotransferase (ALT), gamma-glutamyl transferase (gamma-GT), and alkaline phosphatase (ALP) activities and in liver weight were detected in rats receiving itraconazole treatment. Interestingly, pretreatment with PB prior to itraconazole reduced the ALT and gamma-GT activities and the liver weight of rats. No changes were observed in rats treated with fluconazole. Pretreatment with SKF 525A induced more severe hepatotoxicity for both itraconazole and fluconazole. CYP 3A activity was inhibited dose-dependently by itraconazole treatment. Itraconazole had no effects on the activity of CYP 1A and 2E. Fluconazole potently inhibited all three isoenzymes of CYP. PB plays a role in hepatoprotection to itraconazole-induced but not fluconazole-induced hepatotoxicity. SKF 525A enhanced the hepatotoxicity of both antifungal drugs in vivo. Therefore, it can be concluded that inhibition of CYP may play a key role in the mechanism of hepatotoxicity induced by itraconazole and fluconazole.
BACKGROUND: In our previous study, the aqueous extract of Channa striatus (family: Channidae) fillet (AECSF) showed an antidepressant-like effect in mice. However, the mechanism of the antidepressant-like effect is unknown.
AIM: The objective of this study was to explore the involvement of monoamines in the antidepressant-like effect of AECSF in mice.
MATERIALS AND METHODS: AECSF was prepared by steaming the fillets of C. striatus. The male ICR mice were pretreated with various monoaminergic antagonists viz., p-chlorophenylalanine (100 mg/kg, i.p.), prazosin (1 mg/kg, i.p.) and yohimbine (1 mg/kg, i.p.), SCH23390 (0.05 mg/kg, s.c.) and sulpiride (50 mg/kg, i.p.) followed by treatment with AECSF and tested in tail suspension test (TST). Two-way ANOVA with Tukey test were used at p < 0.05 for significance.
RESULTS: The pretreatments with p-chlorophenylalanine, prazosin and yohimbine, but not with SCH23390 and sulpiride, were able to reverse the antidepressant-like effect of AECSF in TST.
CONCLUSIONS: The antidepressant-like effect of AECSF may be mediated through the serotonergic and noradrenergic systems and not through the dopaminergic system.
Interferon-gamma (IFN-γ) is known to potentiate the progression of inflammatory diseases, such as inflammatory bowel disease and atherosclerosis. IFN-γ has been found to disrupt the barrier integrity of epithelial and endothelial cell both in vivo and in vitro. However, the mechanisms of IFN-γ underlying increased endothelial cell permeability have not been extensively elucidated. We reported that IFN-γ exhibits a biphasic nature in increasing endothelial permeability. The changes observed in the first phase (4-8 h) involve cell retraction and rounding in addition to condensed peripheral F-actin without a significant change in the F-/G-actin ratio. However, cell elongation, stress fiber formation, and an increased F-/G-actin ratio were noticed in the second phase (16-24 h). Consistent with our finding from the permeability assay, IFN-γ induced the formation of intercellular gaps in both phases. A delayed phase of increased permeability was observed at 12 h, which paralleled the onset of cell elongation, stress fiber formation, and increased F-/G-actin ratio. In addition, IFN-γ stimulated p38 mitogen-activated protein (MAP) kinase phosphorylation over a 24 h period. Inhibition of p38 MAP kinase by SB203580 prevented increases in paracellular permeability, actin rearrangement, and increases in the F-/G-actin ratio caused by IFN-γ. Our results suggest that p38 MAP kinase is activated in response to IFN-γ and causes actin rearrangement and altered cell morphology, which in turn mediates endothelial cell hyperpermeability. The F-/G-actin ratio might be involved in the regulation of actin distribution and cell morphology rather than the increased permeability induced by IFN-γ.
Asthma is associated with increased pulmonary inflammation and airway hyperresponsiveness. The interaction between airway epithelium and inflammatory mediators plays a key role in the pathogenesis of asthma. In vitro studies evaluated the inhibitory effects of 3-(2,5-dimethoxyphenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-one (DMPF-1), a synthetic chalcone analogue, upon inflammation in the A549 lung epithelial cell line. DMPF-1 selectively inhibited TNF-α-stimulated CC chemokine secretion (RANTES, eotaxin-1, and MCP-1) without any effect upon CXC chemokine (GRO-α and IL-8) secretion. Western blot analysis further demonstrated that the inhibitory activity resulted from disruption of p65NF-κB nuclear translocation without any effects on the mitogen-activated protein kinase (MAPK) pathway. Treatment of ovalbumin-sensitized and ovalbumin-challenged BALB/c mice with DMPF-1 (0.2-100 mg/kg) demonstrated significant reduction in the secretion and gene expression of CC chemokines (RANTES, eotaxin-1, and MCP-1) and Th2 cytokines (IL-4, IL-5, and IL-13). Furthermore, DMPF-1 treatment inhibited eosinophilia, goblet cell hyperplasia, peripheral blood total IgE, and airway hyperresponsiveness in ovalbumin-sensitized and ovalbumin-challenged mice. In conclusion, these findings demonstrate the potential of DMPF-1, a nonsteroidal compound, as an antiasthmatic agent for further pharmacological evaluation.