Antiulcer activity of the chloroform extract of Bauhinia purpurea leaf

CONTEXT

Bauhinia purpurea L. (Fabaceae) is a native plant species of many Asian countries, including Malaysia and India. In India, the root, stem, bark, and leaf of B. purpurea are used to treat various ailments, including ulcers and stomach cancer.

OBJECTIVE

In an attempt to establish its pharmacological potential, we studied the antiulcer activity of lipid-soluble extract of B. purpurea obtained via extraction of air-dried leaves using chloroform.

MATERIALS AND METHODS

The rats were administered the chloroform extract (dose range of 100-1000 mg/kg) orally after 24 h fasting. They were subjected to the absolute ethanol- and indomethacin-induced gastric ulcer, and pyloric ligation assays after 30 min. The acute toxicity study was conducted using a single oral dose of 5000 mg/kg extract and the rats were observed for the period of 14 days. omeprazole (30 mg/kg) was used as the standard control.

RESULTS

At 5000 mg/kg, the extract produced no sign of toxicity in rats. The extract exhibited significant (p < 0.05) dose-dependent antiulcer activity for the ethanol-induced model. The extract also significantly (p < 0.05) increased the gastric wall mucus production and pH of gastric content, while significantly (p < 0.05) reducing the total volume and total acidity of the gastric content in the pylorus ligation assay.

DISCUSSION AND CONCLUSION

The extract possesses antiulcer, antisecretory and cytoprotective activities, which could be attributed to its flavonoid and tannin content. These findings provide new information regarding the potential of lipid-soluble compounds of B. purpurea for the prevention and treatment of gastric ulcers.

Free radical scavenging activity of conjugated linoleic acid as single or mixed isomers

CONTEXT

Conjugated linoleic acids (CLAs) are a mixture of positional and geometric isomers of linoleic acid (LA) and believed to have many positive biological activities.

OBJECTIVE

The present study was undertaken to assess the antioxidant activity of cis-9, trans-11 and trans-10, cis-12 as single or mixed CLA isomers at two ratios, 1:6 and 1:13 (trans-10, cis-12/cis-9, trans-11).

MATERIALS AND METHODS

A microplate reader was used to determine the free radical scavenging properties of CLAs against DPPH radical in ethanol.

RESULTS

The kinetic reactions of CLA-DPPH(•) showed that all tested CLAs have exerted radical scavenging activities in a dose-dependent manner and observed to immediately react and quench DPPH radicals at all tested levels and no lag phase was noticed in CLA-DPPH(•) reactions. The median inhibitory concentration (IC₅₀) value for cis-9, trans-11 CLA was observed to be more effective than other tested CLA. Total antioxidant capacity (TAC) of all tested CLAs were less effective radical scavengers as compared to vitamin E and butylated hydroxytoluene, although all tested CLAs were quenched a high amount (P < 0.05) of DPPH free radicals.

DISCUSSION AND CONCLUSION

All tested CLAs have the ability to directly react and quench DPPH free radicals in ethanol. Furthermore, trans-10, cis-12 CLA has greater maximal efficacy than other tested CLAs as free radical scavenger, while cis-9, trans-11 CLA is the most potent isomer to directly react and quench free radicals at low concentrations in the system, suggesting that the free radical scavenging activity of CLA isomers may contribute to their diverse biological activities.

Antiulcer activity of methanol extract of Melastoma malabathricum leaves in rats

OBJECTIVE

To determine the potential antiulcer activity of methanol extract of Melastoma malabathricum leaves (MEMM) using various established rat models.

MATERIALS AND METHODS

Ten groups of rats were used and orally administered 10% DMSO (negative control), 100 mg/kg ranitidine (positive control) or MEMM (50, 250 and 500 mg/kg) followed by gastric ulcer induction either using ethanol or indomethacin. The stomachs were collected and subjected to macroscopic and microscopic analyses.

RESULTS

MEMM exhibited significant (p < 0.05) antiulcer activity in the ethanol, but not in the indomethacin-induced gastric ulcer model. The percentage of antiulcer activity for 50-500 mg/kg MEMM ranged between 3 and 75%, respectively. The gross observations were supported by histological findings. MEMM also aggravated the indomethacin-induced gastric ulcer, leading to an increase in ulcer area formation and ulcer score.

CONCLUSION

The M. malabathricum leaves showed antiulcer activity, which could be attributed to their antioxidant and anti-inflammatory activities. This requires further in-depth studies.

Methanol extract of Bauhinia purpurea leaf possesses anti-ulcer activity

OBJECTIVE

The aim of the present study was to determine the anti-ulcer activity of a methanol extract of Bauhinia purpurea leaf (MEBP).

MATERIALS AND METHODS

MEBP was administered at doses of 100, 500 and 1,000 mg/kg and its effects on acute toxicity, absolute ethanol- and indomethacin-induced gastric ulceration, and pyloric ligation tests in rats were investigated.

RESULTS

At a dose of 5,000 mg/kg, MEBP did not cause any signs of toxicity in rats when given orally. Oral administration of MEBP exerted anti-ulcer activity (p < 0.05) in all models tested. However, a dose-dependent protection was observed only in the indomethacin-induced gastric ulceration model. Histological studies supported the observed anti-ulcer activity of MEBP. In the pyloric ligation assay, MEBP significantly increased gastric wall mucus secretion (p < 0.05), but did not affect the acidity of the gastric contents.

CONCLUSION

MEBP exhibited anti-ulcer activity, which could be due to the presence of flavonoids, saponins or other polyphenols, thereby validating the traditional use of B. purpurea in the treatment of ulcers.

Characterization and antimicrobial activities of two Streptomyces isolates from soil in the periphery of Universiti Putra Malaysia

This study was to assess the identification and antimicrobial activities of two actinomycete isolates. The two isolates designated as B8 and C2, were isolated from a patch of soil in the peripheral area of Universiti Putra Malaysia by streaking on starch casein agar after standard serial dilution procedures. Their antimicrobial activities were first evaluated against eight clinical laboratory strains namely Bacillus sp., Enterococcus sp., Escherichia coli, Klebsiella sp., Pseudomonas sp., Salmonella sp., Staphylococcus aureus, and Staphylococcus epidermidis by perpendicular streak method on Mueller Hinton and Tryptic Soy agar. In both media, a broad-spectrum antibacterial activity was observed for both isolates, with B8 against all the test bacteria and C2 against five of them (Bacillus sp., E. coli, Pseudomonas sp., S. aureus and S. epidermidis). Re-assessment against E. coli ATCC 25922 and S. aureus ATCC 25923 strains by similar method showed antibacterial activities by isolate B8 against both ATTC strains while C2 only against S. aureus ATCC 25923. Streptomyces griseus ATCC 10137 was included in the later experiment and showed antibacterial activity against both ATCC strains. Subsequently, the two isolates were identified by PCR/sequencing techniques and phylogenetic analysis to be Streptomyces species (>93% homology based on 16S rRNA and rpoB genes). Characterization on cultural characteristic and viable count at different temperatures (37ºC and 28ºC), on different microbiological media (AIA, ISP-2, MHA, NA, PDA and TSA), were performed. More morphological features were observed on ISP-2 for both isolates. A higher growth yield was also observed at 28ºC in all media but in comparing that between the two isolates, isolate B8 outnumbered C2 at all experimental conditions. The observed variation in cultural traits and growth yield indicate unique properties between the two antibiotic-producing isolates.

In vivo antiulcer activity of the aqueous extract of Bauhinia purpurea leaf

ETHNOPHARMACOLOGICAL RELEVANCE

Bauhinia purpurea (Fabaceae) is a medicinal plant traditionally used to treat various ailments, including ulcers. In order to establish pharmacological properties of the leaf of Bauhinia purpurea, studies were performed on antiulcer activity of the plant's aqueous extract.

MATERIALS AND METHODS

The Bauhinia purpurea aqueous extract (BPAE) was prepared in the doses of 100, 500 and 1,000 mg/kg. Antiulcer activity of BPAE was evaluated by absolute ethanol- and indomethacin-induced gastric ulcer, and pyloric ligation models. Acute toxicity was also carried out.

RESULTS

BPAE, at the dose of 5,000 mg/kg, did not cause any signs of toxicity to rats when given orally. Oral administration of BPAE exhibited antiulcer activity (p<0.05) in all models used. However, the dose-dependent activity was observed only in the absolute ethanol-induced gastric ulcer model. Histological studies supported the observed antiulcer activity of BPAE. In pyloric ligation assay, BPAE increased the gastric wall mucus secretion.

CONCLUSIONS

The BPAE exhibits antiulcer activity, which could be due to the presence of saponins or sugar-free polyphenols, and, thus, confirmed the traditional uses of Bauhinia purpurea in the treatment of ulcers.

Anti-inflammatory activity of the aqueous extract of ficus deltoidea

Ficus deltoidea (Family Moraceae) leaves have been used traditionally by the Malays to treat ailments such as wounds, sores, and rheumatism. The aim of the present study was to determine the anti-inflammatory activity of the aqueous extract of F. deltoidea leaf (FDA) using acute and chronic inflammatory models. FDA, in the doses of 30, 100, and 300 mg/kg, was administered intraperitoneally in rats (n = 6) before the animals were subjected to the carrageenan-induced paw edema test, cotton pellet-induced granuloma test, and formalin test. The first two tests represent acute and chronic models of inflammation, respectively. The first and second phases of the formalin test represent neurogenic pain and inflammatory-mediated pain, respectively; thus, only the second phase was measured in the present study. Results showed that FDA exerted significant (p < .05) anti-inflammatory activity in all assays, with dose-response effects seen in the paw edema and formalin tests. In conclusion, the leaf of F. deltoidea possesses anti-inflammatory activity against acute and chronic inflammatory responses and against pain-associated inflammatory response. These findings justify the traditional uses of F. deltoidea leaves for treatment of inflammatory-mediated ailments.

Antinociceptive activity of methanolic extract of Acmella uliginosa (Sw.) Cass

ETHNOPHARMACOLOGICAL RELEVANCE

Acmella uliginosa (Sw.) Cass. is a medicinal herbaceous plant that is commonly used by the Malay community in Malaysia to relieve pain often associated with mouth ulcers, toothache, sore throat, and stomach ache.

AIM

The study was carried out to investigate the antinociceptive effect of the methanolic extract of A. uliginosa (Sw.) Cass. flowers (MEAU) using murine models of chemicals and thermal nociception.

MATERIALS AND METHODS

Chemicals (acetic acid-induced abdominal constriction and formalin-, capsaicin-, glutamate-induced paw licking test) and thermal models (hot plate test) of nociception in mice were employed to evaluate the MEAU analgesic effect. The extract was given via oral administration at doses of 3, 10, 30 and 100 mg/kg.

RESULTS

It was demonstrated that MEAU produced significant antinociceptive response in all the chemical- and thermal-induced nociception models, which indicates the presence of both centrally and peripherally mediated activities. Furthermore, the reversal of antinociception of MEAU by naloxone suggests the involvement of opioid system in its centrally mediated analgesic activity. Moreover, MEAU-treated mice did not show any significant motor performance alterations. No mortality and signs of toxicity were recorded following treatment of the MEAU.

CONCLUSION

The results from the present study appear to support the folkloric belief in the medicinal properties of A. uliginosa (Sw.) Cass. which against pain at both central and peripheral levels, in which the central antinociception is probably due to the participation of the opioid receptors.

In vivo antinociceptive and anti-inflammatory activities of dried and fermented processed virgin coconut oil

OBJECTIVE

The present study was carried out to investigate the antinociceptive and anti-inflammatory activities of virgin coconut oil (VCO) produced by the Malaysian Agriculture Research and Development Institute (MARDI) using various in vivo models.

MATERIALS AND METHODS

Two types of VCOs, produced via standard drying (VCOA) and fermentation (VCOB) processes were used in this study. Both VCOA and VCOB were serially diluted using 1% Tween 80 to concentrations (v/v) of 10, 50 and 100%. Antinociceptive and anti- inflammatory activities of both VCOs were examined using various in vivo model systems. The antinociceptive activity of the VCOs were compared to those of 1% Tween 80 (used as a negative control), morphine (5 mg/kg) and/or acetylsalicylic acid (100 mg/kg).

RESULTS

Both VCOA and VCOB exhibited significant (p < 0.05) dose-dependent antinociceptive activity in the acetic acid-induced writhing test. Both VCOs also exerted significant (p < 0.05) antinociceptive activity in both phases of the formalin and hot-plate tests. Interestingly, the VCOs exhibited anti-inflammatory activity in an acute (carrageenan-induced paw edema test), but not in a chronic (cotton-pellet-induced granuloma test) model of inflammation.

CONCLUSION

The MARDI-produced VCOs possessed antinociceptive and anti-inflammatory activities. Further studies are needed to confirm these observations.

A prospective study on the pattern of medication use for schizophrenia in the outpatient pharmacy department, Hospital Tengku Ampuan Rahimah, Selangor, Malaysia

Schizophrenia is a chronic psychiatric disorder and pharmacotherapy plays a major role in its management. The 1950s and early 1960s saw milestones in the introduction of psychotropic drugs in clinical practice. A review of drug prescriptions in different settings provides an insight into the pattern of drug use, identifies drug-related problems and may be used to compare recommended guidelines with actual practice. This effort led to the evaluation of the drug prescribing pattern of antipsychotics in patients attending the psychiatric clinic at a government hospital. The data from 371 antipsychotic medication prescriptions that included 200 prescriptions for schizophrenia were collected during one month (1rst-31rst August 2008) at the outpatient pharmacy department. The mean age of patients was 35.0 years (SD = 1.131), with a male to female ratio of 2:1. The most widely used oral antipsychotic was haloperidol (16.3%) while the most common depot preparation prescribed was zuclopenthixol decanoate (8.8%). The daily dose of the average antipsychotic prescribed in this clinic was 342.06 mg equivalent of chlorpromazine. There was no relation between the doses received and ethnicity of the patient (Malay, Chinese or Indian). However, there was a significant relationship between the prescribed dose and patient age (P < 0.042). Nearly 32% of the schizophrenia patients were prescribed with atypical antipsychotics such as olanzapine (10.8%), risperidone (10.0%), quetiapine (7.6%) and clozapine (3.2%). Monotherapy was given to 73.0% of the schizophrenia patients. The majority of patients also received antidepressants. To conclude, this study gave evidence that physicians had a strong preference for monotherapy with conventional antipsychotic drugs while the use of atypical drugs was less prevalent.

A synthetic hydroxypropenone inhibits nitric oxide, prostaglandin E2, and proinflammatory cytokine synthesis

HMP [3-(2-hydroxyphenyl)-1-(5-methyl-furan-2-y-l) propenone] was evaluated for its ability to inhibit the synthesis of major proinflammatory mediators and cytokines in interferon-gamma (IFN-gamma)- and lipopolysaccharide (LPS)-induced RAW 264.7 cells and phorbol myristate acetate (PMA)-differentiated/LPS-induced U937 cells. HMP suppressed the production of nitric oxide (NO) with significant inhibitory effects at doses as low as 0.78 microM (P < 0.05). Prostaglandin E2 (PGE2) secretion was also inhibited at doses of 12.5 microM and above (P < 0.01). The secretion of both TNF-alpha and IL-6 were only inhibited at the highest dose used (25 microM; P < 0.001). IL-1beta secretion was also inhibited from 12.5 microM onwards (P < 0.01). This inhibition was demonstrated to be caused by down-regulation of inducible enzymes, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), without direct effect upon iNOS or COX-2 enzyme activity. HMP only inhibited iNOS (P < 0.001) and IL-1beta (P < 0.05) gene expression at the highest tested concentration. HMP did not affect the secretion of chemokines IL-8 and monocyte chemotactic protein-1 (MCP-1) and the anti-inflammatory cytokine IL-10. The most striking effect of HMP was its NO inhibitory activity and therefore we conclude that HMP is a selective inhibitor of iNOS.

Zerumbone-induced antinociception: involvement of the L-arginine-nitric oxide-cGMP -PKC-K+ ATP channel pathways

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.

Antinociceptive and anti-inflammatory effects of the ethanol extract of Alpinia conchigera rhizomes in various animal models

Alpinia conchigera Griff. (Zingiberaceae), locally known to the Malays as "lengkuas ranting", is native to Peninsular Malaysia. The Malays traditionally used it to treat infection and rashes, and as a health drink. This study evaluated the analgesic and anti-inflammatory activities of the ethanol extract of A. conchigera rhizomes in mice and rats, respectively. The analgesic activity was elucidated using the acetic acid-induced writhing test, hot plate test, and formalin test, while the anti-inflammatory activity was determined using carrageenan-induced paw edema. The extract (30, 100, and 300 mg/kg) given intraperitoneally (i.p.) exhibited antinociceptive and anti-inflammatory activities in all tests used. The range of percentage of analgesia obtained for all doses of extract in the writhing test was 50-92%, and in the early and late phases of the formalin test was 25-62% and 63-98%, respectively. In addition, naloxone (5 mg/kg) given subcutaneously (s.c.) was found to reverse the extract (300 mg/kg)-induced antinociceptive activity in the writhing, hot plate, and formalin tests. Based on the results obtained, it can be concluded that the ethanol extract of A. conchigera rhizomes possessed a peripheral and central antinociceptive activity that was mediated, in part, via the opioid receptor, as well as anti-inflammatory activity.

Atrovirinone inhibits proinflammatory mediator synthesis through disruption of NF-kappaB nuclear translocation and MAPK phosphorylation in the murine monocytic macrophage RAW 264.7

In a previous communication we showed that atrovirinone, a 1,4-benzoquinone isolated from the roots of Garcinia atroviridis, was able to inhibit several major proinflammatory mediators of inflammation. In this report we show that atrovirinone inhibits NO and PGE(2) synthesis through inhibition of iNOS and COX-2 expression. We also show that atrovirinone inhibits the secretion of IL-1beta and IL-6 in a dose dependent fashion whereas the secretion of IL-10, the anti-inflammatory cytokine, was enhanced. Subsequently we determined that the inhibition of proinflammatory cytokine synthesis and inducible enzyme expression was due to a dose-dependent inhibition of phosphorylation of p38 and ERK1/2. We also showed that atrovirinone prevented phosphorylation of I-kappaBalpha, which resulted in a reduction of p65NF-kappaB nuclear translocation as demonstrated by expression analysis. We conclude that atrovirinone is a potential anti-inflammatory drug lead that targets both the MAPK and NF-kappaB pathway.

Anti-inflammatory effect of zerumbone on acute and chronic inflammation models in mice

The anti-inflammatory activity of zerumbone (1), a natural cyclic sesquiterpene isolated from Zingiber zerumbet Smith was investigated using carrageenan-induced paw edema and cotton pellet-induced granuloma tissue formation test in mice. It was demonstrated that intraperitoneal administration of 1 at a dose of 5, 10, 50 and 100 mg/kg produced significant dose-dependent inhibition of paw edema induced by carrageenan. It was also demonstrated that 1 at similar doses significantly suppressed granulomatous tissue formation in cotton pellet-induced granuloma test.

Antiinflammatory and antinociceptive activities of Zingiber zerumbet methanol extract in experimental model systems

OBJECTIVE

The present study was carried out to determine the antiinflammatory and antinociceptive activities of a methanol extract of Zingiber zerumbet rhizomes (MEZZ) using various experimental model systems.

MATERIALS AND METHODS

The MEZZ was prepared by macerating oven-dried (50 degrees C) powdered rhizomes (1.2 kg) of Z. zerumbet in 80% methanol in a ratio of 1:20 (w/v) for 48 h. The supernatant was collected, filtered and evaporated to dryness under reduced pressure (50 degrees C) yielding approximately 21.0 g of the crude dried extract. The crude dried extract was stored at -20 degrees C prior to use and was dissolved in normal saline (0.9% NaCl) immediately before administration at concentrations required to produce doses of 25, 50 and 100 mg/kg.

RESULTS

All dosages of MEZZ showed significant (p < 0.05) antiedema activity when assessed using the carrageenan-induced paw edema test and the cotton-pellet-induced granuloma test. The MEZZ exhibited significant (p < 0.05) antinociceptive activity when assessed by the writhing, hot plate and formalin tests. Pretreatment with naloxone (5 mg/kg) significantly decreased the latency of discomfort produced by the 100 mg/kg dose of MEZZ in the hot plate test.

CONCLUSION

MEZZ produced antiinflammatory and antinociceptive activities which may involve the inhibition of bradykinin-, prostaglandin-, histamine- and opioid-mediated processes.

In vivo anti-nociceptive and anti-inflammatory activities of the aqueous extract of the leaves of Piper sarmentosum

ETHNOPHARMACOLOGICAL RELEVANCE

Piper sarmentosum (Piperaceae) is a medicinal plant traditionally used by the Malays to treat headaches, toothaches, coughs, asthma and fever.

AIM OF THE STUDY

In order to establish the pharmacological properties of the leaf of this plant, studies were performed on anti-nociceptive and anti-inflammatory activities.

MATERIALS AND METHODS

The aqueous extract of Piper sarmentosum (AEPS) was prepared in the doses of 30, 100 and 300 mg/kg. Anti-nociceptive activity of AEPS was evaluated by abdominal constriction and hot-plate tests. AEPS was also pre-challenged with 5mg/kg naloxone to determine the involvement of opioid receptors. Anti-inflammatory activity was evaluated using carrageenan-induced paw edema assay.

RESULTS

Subcutaneous administration of AEPS exhibited anti-nociceptive activity (P<0.05) in a dose-dependent manner in the abdominal constriction and hot-plate tests. Pre-treatment with naloxone completely (P<0.05) diminished the extract anti-nociceptive activity in both tests. The AEPS, at all doses used, exerted significant (P<0.05) anti-inflammatory activity in a dose-dependent manner.

CONCLUSIONS

The AEPS exhibits opioid-mediated anti-nociceptive activity at the peripheral and central levels, as well as anti-inflammatory activity, which confirmed the traditional uses of the plant in the treatment of pain- and inflammatory-related ailments.

Screening of microfilaricidal effects of plant extracts against Dirofilaria immitis

Canine dirofilariasis is a common tropical parasitic disease of companion animals, caused by infestation of Dirofilaria immitis filarids within the pulmonary arteries and extending into the right heart. Increased reports of adverse reactions elicited by current microfilaricidal agents against D. immitis such as neurological disorders, circulatory collapse and potential resistance against these agents, warrant the search for new agents in forms of plant extracts. The use of plant extracts in therapeutic medicine is commonly met with scepticism by the veterinary community, thus the lack of focus on its medical potential. This study evaluated the presence of microfilaricidal activities of the aqueous extracts of Zingiber officinale, Andrographis paniculata and Tinospora crispa Miers on D. immitisin vitro at different concentrations; 10mg/ml, 1mg/ml, 100 microg/ml, 10 microg/ml and 1 microg/ml within 24h, by evaluation of relative microfilarial motility as a measure of microfilaricidal activity. All extracts showed microfilaricidal activity with Z. officinale exhibiting the strongest activity overall, followed by A. paniculata and T. crispa Miers. It is speculated that the microfilaricidal mechanism exhibited by these extracts is via spastic paralysis based upon direct observation of the microfilarial motility.

Antinociceptive activity of the essential oil of Zingiber zerumbet

In the present study, the rhizome essential oil from Zingiber zerumbet (Zingiberaceae) was evaluated for antinociceptive activity using chemical and thermal models of nociception, namely, the acetic acid-induced abdominal writhing test, the hot-plate test and the formalin-induced paw licking test. It was demonstrated that intraperitoneal administration of the essential oil of Z. zerumbet (EOZZ) at the doses of 30, 100 and 300 mg/kg produced significant dose-dependent inhibition of acetic acid-induced abdominal writhing, comparable to that of obtained with acetylsalicylic acid (100 mg/kg). At the same doses, the EOZZ produced significant dose-dependent increases in the latency time in the hot-plate test with respect to controls, and in the formalin-induced paw licking test, the EOZZ also significantly reduced the painful stimulus in both neurogenic and inflammatory phase of the test. In addition, the antinociceptive effect of the EOZZ in the formalin-induced paw licking test as well as hot-plate test was reversed by the nonselective opioid receptor antagonist, naloxone suggesting that the opioid system was involved in its analgesic mechanism of action. On the basis of these data, we concluded that the EOZZ possessed both central and peripheral antinociceptive activities which justifying its popular folkloric use to relieve some pain conditions.

In vivo analgesic effect of aqueous extract of Tamarindus indica L. fruits

OBJECTIVE

To study the effects of Tamarindus indica L. aqueous fruit extract on the antinociceptive activities in rodent models.

METHODS

The analgesic effect was evaluated using acetic acid-induced writhing, hot plate and formalin tests.

RESULTS

The extract (60-600 mg/kg) significantly (p < 0.05) inhibited the writhing test in a dose-dependent manner with the percentage of analgesia recorded between 51.8 and 74.1%. In addition, the extract also significantly (p < 0.05) increased the latency time in the hot plate test in a dose-dependent manner. Further study showed that the extract elicited inhibitory activity in both the early and late phases of the formalin test. Moreover, pretreatment with 5 mg/kg naloxone, a nonselective opioid receptor antagonist, significantly (p < 0.05) modified the antinociceptive effect of the extract in all tests.

CONCLUSION

The aqueous extract of T. indica possesses potential antinociceptive activity at both the peripheral and central levels, which are mediated via activation of the opioidergic mechanism.

Antinociceptive and anti-inflammatory effects of the ethanol extract of Alpinia conchigera Griff. leaves in various animal models

The ethanolic extract of Alpinia conchigera Griff. leaves (EACL) was evaluated for its antinociceptive and anti-inflammatory activities in several in vivo experimental models. Antinociceptive activity was determined using the acetic acid-induced abdominal writhing test, the hot plate test and the formalin test. Anti-inflammatory activity was determined using the carrageenan-induced paw edema test. The extract (30, 100 and 300 mg/kg i.p.) was found to possess significant, dose-dependent inhibitory activity in all test models. In addition, the antinociceptive effect of the extract in the acetic acid-induced writhing and hot plate tests was reversed by naloxone, suggesting that this activity is mediated through activation of the opioid system. These findings suggest that EACL presents notable analgesic and anti-inflammatory activities, which support its folkloric use for painful and inflammatory conditions.

Antinociceptive, anti-inflammatory and antipyretic effects of Solanum nigrum aqueous extract in animal models

The present study was carried out to evaluate the antinociceptive, anti-inflammatory and antipyretic effects of the aqueous extract of Solanum nigrum leaves using various animal models. The extract, at concentrations of 10, 50 and 100%, was prepared by soaking (1:20; w/v) air-dried powdered leaves (20 g) in distilled water (dH2O) for 72 h. The extract solutions were administered subcutaneously in mice/rats 30 min prior to the tests. The extract exhibited significant (P < 0.05) antinociceptive activity when assessed using the abdominal constriction, hot plate and formalin tests. The extract also produced significant (P < 0.05) anti-inflammatory and antipyretic activities when assessed using the carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests, respectively. Overall, these activities occurred in a concentration-dependent manner, except for the 50% concentration of the extract, which was not effective in the abdominal constriction test. In conclusion, the present study demonstrated that S. nigrum leaves possessed antinociceptive, anti-inflammatory and antipyretic effects and thus supported traditional claims of its medicinal uses.

Diuretic properties of Orthosiphon stamineus Benth

ETHNOPHARMACOLOGICAL RELEVANCE

Orthosiphon stamineus has been used in traditional medicine for centuries especially to treat diseases of the urinary system.

AIM OF THE STUDY

To investigate the diuretic activity, to elucidate its possible mechanism and to evaluate the renal effects of Orthosiphon stamineus extract.

MATERIALS AND METHODS

Water extracts were administered orally at doses of 5 and 10 mg/kg to Sprague-Dawley rats and the control groups were given commercial diuretic drugs either furosemide or hydrochlorthiazide at 10 mg/kg. Urine volume, urine pH, urine density and urine electrolytes were determined every hour for 4h. Blood was assayed for glucose, albumin, blood urea nitrogen (BUN) and creatinine.

RESULTS

O. stamineus extract exhibited dose-dependent diuretic activity. However, excretion of Na+ and Cl(-) was not markedly elevated, but urinary excretion of K+ was significantly increased. O. stamineus extracts slightly increased the serum BUN, creatinine and blood glucose level. Although these levels were statistically significant when compared to control, these levels were still within normal range.

CONCLUSIONS

O. stamineus exhibited diuretic activity, but was less potent than furosemide and hydrochlorothiazide. Care should be taken when consuming this herb as slight increase of kidney function enzymes was recorded.

Antinociceptive and antiinflammatory activities of the aqueous extract of Trigonopleura malayana resin in experimental animal models

Trigonopleura malayana L. (Euphorbiaceae) resin, locally known as Gambir Sarawak, has been used traditionally to alleviate pain associated with insect bites, muscle ache, toothache and minor injuries. The present study was carried out using various animal models to determine the antinociceptive and antiinflammatory activities of the T. malayana resin aqueous extract. Antinociceptive activity was measured using the abdominal constriction, hot plate and formalin tests, while antiinflammatory activity was measured using the carrageenan-induced paw edema test. The extract, obtained after 24 h of soaking the dried resin in distilled water, was prepared in doses of 0.3, 3 and 10 mg/kg and administered subcutaneously 30 min prior to the assays. The mechanism of action was also determined by prechallenging with naloxone (10 mg/kg), a nonselective opioid antagonist. The extract was found to exhibit significant (P < 0.05) and dose-dependent antinociceptive and antiinflammatory activities; naloxone failed to inhibit the former activity. In conclusion, the aqueous extract of T. malayana resin possesses nonopioid antinociceptive and antiinflammatory activities, thus supporting previous claims regarding its traditional use by the Malays to treat various ailments, particularly those related to pain.

Preliminary analysis of the antinociceptive activity of zerumbone

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.

Antinociceptive, antiinflammatory and antipyretic properties of Channa striatus fillet aqueous and lipid-based extracts in rats

The present study was carried out to elucidate the antinociceptive, antiinflammatory and antipyretic properties of the aqueous and lipid-based extracts of Channa striatus fillet in rats. The antinociceptive activity was assessed using the formalin test, and the antiinflammatory and antipyretic activities were assessed using the carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests, respectively. Both types of extracts were prepared in concentrations of 10%, 50% and 100% by serial dilution in distilled water or dimethyl sulfoxide, respectively, and were administered subcutaneously 30 min prior to each test. Except for the 10% aqueous extract which exhibits activity only in the early phase, the extracts were found to exhibit significant (P < 0.05) activity in the early and late phases of the formalin test. Furthermore, the aqueous and lipid-based extracts were also found to show significant (P < 0.05) antiinflammatory activity, with the former showing a greater effect at the lowest concentration used. The lipidbased, but not the aqueous, extract was found to have significant (P < 0.05) activity in the pyrexia test. In conclusion, the present study demonstrated that C. striatus extracts possess antinociceptive, antiinflammatory and antipyretic activities.

Anti-inflammatory and antinociceptive effects of Mitragyna speciosa Korth methanolic extract

OBJECTIVES

To determine the anti-inflammatory and antinociceptive activities of Mitragyna speciosa Korth methanol extract in rodents.

MATERIALS AND METHODS

Anti-inflammatory activity was evaluated using carrageenan-induced paw edema and cotton pellet-induced granuloma tests in rats. Antinociceptive activity was measured using the writhing test and the hot plate test in mice, and the formalin test in rats. All drugs and extracts were diluted in dH(2)O and administered through the intraperitoneal route. Results were analyzed using one-way ANOVA followed by Dunnett's test for multiple comparisons among groups.

RESULTS

Results showed that intraperitoneal administration of the extract at doses of 100 and 200 mg/kg produced significant dose-dependent activity in all of the nociceptive models evaluated (p < 0.05). With the formalin test, the antinociceptive activity in mice was inhibited only at the highest dose of the extract (200 mg/kg). The study also showed that intraperitoneal administration of the methanol extract of M. speciosa (100 and 200 mg/kg) significantly and dose-dependently suppressed the development of carrageenan-induced rat paw edema (p < 0.05). In the chronic test, however, significant reduction in granulomatous tissue formation in rats was observed only at the highest dose of the methanol extract of M. speciosa (200 mg/kg, p < 0.05).

CONCLUSION

The present study suggests the presence of potent antinociceptive and anti-inflammatory principles in the extract, supporting its folkloric use for the treatment of these conditions.

Antinociceptive and anti-inflammatory effects of Stachytarpheta jamaicensis (L.) Vahl (Verbenaceae) in experimental animal models

OBJECTIVE

The present study was carried out to explore the antinociceptive as well as the anti-inflammatory effects of an ethanol extract of Stachytarpheta jamaicensis (L.) Vahl (EESJ) using 3 models of nociception and 2 models of inflammation in experimental animals.

MATERIALS AND METHODS

EESJ was prepared by overnight soaking of the oven-dried (50 degrees C; 72 h) ground leaves (500 g) in 80% ethanol (1:5; w/v). The filtrate was evaporated to dryness (50 degrees C), resuspended in distilled water at concentrations to provide the desired doses of 50, 100 and 150 mg/kg. For antinociceptive effects, 3 models were used: acetic acid-induced abdominal writhing, hot-plate- and formalin-induced paw-licking tests; for anti-inflammatory effects, 2 models were used--carrageenan-induced paw edema and cotton-pellet-induced granuloma tests. Appropriate doses were administered intraperitoneally (i.p.) to mice/rats prior to each test. The mechanisms of antinociceptive action of the extract were also investigated by pretreatment with naloxone (5 mg/kg, i.p.).

RESULTS

The extract exhibited significant (p < 0.05) antinociceptive activity in all nociceptive models tested with dose-dependent activity observed using the abdominal writhing and formalin tests. Pretreatment with naloxone partially, but significantly (p < 0.05) reversed the antinociceptive activity of the extract when assessed using the abdominal-writhing- and formalin-induced paw-licking tests, and completely inhibited its activity when the hot-plate test was used. The extract also showed significant (p < 0.05) anti-inflammatory activity in both the acute (carrageenan-induced paw edema test) and the chronic (cotton-pellet granuloma test) tests.

CONCLUSION

This study showed the potential of EESJ to exert antinociceptive and anti-inflammatory activities, the former being modulated via peripheral and central mechanisms and involving, in part, activation of the opioid receptor system.

Amino acid and fatty acid composition of an aqueous extract of Channa striatus (Haruan) that exhibits antinociceptive activity

1. The present study was performed in order to determine the amino acid and fatty acid composition of an aqueous extract of the freshwater fish Channa striatus, obtained by soaking (1:2, w/v) fresh fillets overnight in a chloroform:methanol (2:1, v/v) solvent, to elucidate the mechanism responsible for its antinociceptive activity and to clarify the relationship between the presence of the amino and fatty acids and the expected activity. 2. The aqueous extract was found to contain all amino acids with the major amino acids glycine, alanine, lysine, aspartic acid and proline making up 35.77 +/- 0.58, 10.19 +/- 1.27, 9.44 +/- 0.56, 8.53 +/- 1.15 and 6.86 +/- 0.78% of the total protein, respectively. 3. In addition, the aqueous extract was found to have a high palmitic acid (C16:0) content, which contributed approximately 35.93 +/- 0.63% to total fatty acids. The other major fatty acids in the aqueous extract were oleic acid (C18:1), stearic acid (C18:0), linoleic acid (C18:2) and arachidonic acid (C20:4), contributing 22.96 +/- 0.40, 15.31 +/- 0.33, 11.45 +/- 0.31 and 7.44 +/- 0.83% of total fatty acids, respectively. 4. Furthermore, the aqueous extract was demonstrated to possess concentration-dependent antinociceptive activity, as expected, when assessed using the abdominal constriction test in mice. 5. It is concluded that the aqueous extract of C. striatus contains all the important amino acids, but only some of the important fatty acids, which are suggested to play a key role in the observed antinociceptive activity of the extract, as well as in the traditionally claimed wound healing properties of the extract.

Antinociceptive and Anti-inflammatory Properties of Corchorus capsularis Leaves Chloroform Extract in Experimental Animal Models

The antinociceptive and anti-inflammatory properties of Corchorus capsularis leaves chloroform extract were investigated in experimental animal models. The antinociceptive activity was measured using the writhing, hot plate and formalin tests, while the anti-inflammatory activity was measured using the carrageenan-induced paw edema test. The extract, obtained after 72 h soaking of the air-dried leaves in chloroform followed by in vacuo evaporation to dryness, was weighed and prepared by serial dilution in DMSO in the doses of 20, 100 and 200 mg/kg. The extract was administered (s.c.) 30 min prior to subjection to the respective assays. The extract was found to exhibit significant (p < 0.05) antinociceptive and anti-inflammatory activities. As a conclusion, the present study confirmed the traditional claims of using C. capsularis to treat various ailments related to inflammation and pain.

Biosorption and bioreduction of Cr(VI) by locally isolated Cr-resistant bacteria

Cr(VI) biosorption and bioreduction ability of locally isolated Cr-resistant bacteria was investigated using the shake-flask technique. A mixture of S. epidermidis and B. cereus showed the highest minimum inhibitory concentration (MIC) level at 750 mg/L Cr(VI) followed by S. aureus and Bacillus sp. of 250 mg/L, and A. haemolyticus of 70 mg/L. From the Langmuir adsorption isotherm, the treatment of cells with heat-acid resulted in the highest amount of Cr(VI) adsorped (78.25 mg/g dry wt. for S. epidermidis) compared to heat-acetone (67.93 mg/g dry wt. Bacillus sp.), heat only (36.05 mg/g dry wt. S. epidermidis) or untreated cells (45.40 mg/g dry wt. S. epidermidis and B. cereus). FTIR analysis showed the involvement of amine groups in Cr(VI) adsorption. In the bioreduction study, A. haemolyticus was able to completely reduce Cr(VI) up to 50 mg/L.

Antinociceptive, anti-inflammatory and antipyretic properties of the aqueous extract of Bauhinia purpurea leaves in experimental animals

OBJECTIVE

The present study was carried out to determine the antinociceptive, anti-inflammatory and antipyretic activities of the aqueous extract of Bauhinia purpurea leaves using animal models.

MATERIALS AND METHODS

The air-dried, powdered leaves (approximately 20 g) were soaked in distilled water (1:20; w/v) at room temperature for 72 h and the supernatant obtained was freeze-dried. The crude dried extract (approximately 2.4 g) was prepared in doses of 6.0, 30.0 and 60.0 mg/kg, and subjected to the respective antinociceptive (abdominal constriction, hot plate and formalin tests), anti-inflammatory (carrageenan-induced paw edema test) and antipyretic (brewer's yeast-induced pyrexia test) assays.

RESULTS

The results obtained indicate that the extract possessed significant (p < 0.05) antinociceptive, anti-inflammatory and antipyretic activities, which were not dependent on the doses of extract used. The highest concentration of extract was less effective as an anti-inflammatory and an antipyretic agent.

CONCLUSION

This study showed that the aqueous extract of B. purpurea leaves possesses potential pharmacological activities that require further investigation and, thus, confirms the folklore use of the plant in the treatment of ailments associated with pain and inflammation.

The antinociceptive action of aqueous extract from Muntingia calabura leaves: the role of opioid receptors

OBJECTIVE

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.

MATERIALS AND METHODS

The extract was prepared by soaking the dried powdered leaves of M. calabura in distilled water (dH(2)O) overnight, and the supernatant obtained was considered as a stock solution with 100% concentration. The stock solution was diluted to 1, 5, 10, 50 and 100% and used to determine the antinociceptive activity of MCAE. A further experiment was done with 50% concentration to determine the effect of temperature and naloxone involvement of the opioid receptor system in MCAE antinociceptive activity.

RESULTS

At the various concentrations MCAE showed significant antinociceptive activity in both tests. However, the concentration-dependent activity was observed only in the ACT but not in the HPT. The 50% concentration of MCAEs were also stable against the effect of various temperatures as indicated by the presence of activity in both tests. The temperatures (40, 60 and 100 degrees C) also showed an enhanced extract activity only in the HPT. Pre-treatment with naloxone (2 and 10 mg/kg) blocked the extract activity in both tests, indicating the involvement of the opioid receptor system in MCAE antinociceptive activity.

CONCLUSION

Our data indicate that M. calabura leaves possess antinociceptive activity against chemically and thermally induced noxious stimuli. The bioactive compound(s) responsible for its antinociceptive activity is/are heat-stable and work partly via the opioid receptor system.

The antinociceptive activity of Muntingia calabura aqueous extract and the involvement of L-arginine/nitric oxide/cyclic guanosine monophosphate pathway in its observed activity in mice

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.

Antinociceptive, anti-inflammatory and antipyretic properties of Melastoma malabathricum leaves aqueous extract in experimental animals

The present study was carried out to establish the antinociceptive, anti-inflammatory, and antipyretic properties of the aqueous extract of Melastoma malabathricum leaves in experimental animals. The antinociceptive activity was measured using abdominal constriction, hot-plate, and formalin tests, whereas the anti-inflammatory and antipyretic activities were measured using carrageenan-induced paw edema and brewer’s yeast-induced pyrexia tests, respectively. The extract, which was obtained after soaking the air-dried leaves in distilled water for 72 h and then preparing in concentrations of 10%, 50%, and 100% (v/v), was administered subcutaneously 30 min prior to subjection to the above mentioned assays. At all concentrations tested, the extract was found to exhibit significant (P < 0.05) antinociceptive, anti-inflammatory, and antipyretic activities in a concentration-independent manner. Our findings that the aqueous extract of M. malabathricum possesses antinociceptive, anti-inflammatory, and antipyretic activities supports previous claims on its traditional uses to treat various ailments.

Antinociceptive, Anti-inflammatory and Antipyretic Effects of Solanum nigrum Chloroform Extract in Animal Models

AIM

The present study was carried out to evaluate the antinociceptive, anti-inflammatory and antipyretic effects of chloroform extract of Solanum nigrum leaves using various animal models.

METHODS

The extract was prepared by soaking (1:20; w/v) the air-dried powdered leaves (20 g) in chloroform for 72 hrs followed by evaporation (40 degrees C) under reduced pressure to dryness (1.26 g) and then dissolved (1:50; w/v) in dimethylsulfoxide (DMSO). The supernatant, considered as the stock solution with dose of 200 mg/kg, was diluted using DMSO to 20 and 100 mg/kg, and all doses were administered (s.c.; 10 ml/kg) in mice/rats 30 min prior to tests.

RESULTS

The extract exhibited significant (p<0.05) antinociceptive activity when assessed using the abdominal constriction, hot plate and formalin tests. The extract also produced significant (p<0.05) anti-inflammatory and antipyretic activities when assessed using the carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests. Overall, the activities occurred in a dose-independent manner.

CONCLUSION

The present study demonstrated that the lipid-soluble extract of S. nigrum leaves possessed antinociceptive, anti-inflammatory and anti-pyretic properties and confirmed the traditional claims.

Antinociceptive and Anti-inflammatory Activities of Dicranopteris linearis Leaves Chloroform Extract in Experimental Animals

The present study was carried out to establish the antinociceptive and anti-inflammatory properties of Dicranopteris linearis leaves chloroform extract in experimental animals. The antinociceptive activity was measured using the abdominal constriction, formalin and hot plate tests, while the anti-inflammatory activity was measured using the carrageenan-induced paw edema. The extract, obtained after 72 h soaking of the air-dried leaves in chloroform followed by evaporation under vacuo (40 degrees C) to dryness, was dissolved in dimethyl sulfoxide to the doses of 20, 100 and 200 mg/kg and administered subcutaneously 30 min prior to subjection to the above mentioned assays. The extract, at all doses used, was found to exhibit significant (p<0.05) antinociceptive activity in a dose-dependent manner. However, the significant (p<0.05) anti-inflammatory activity observed occur in a dose-independent manner. As a conclusion, the chloroform extract of D. linearis possesses antinociceptive and anti-inflammatory activity and thus justify its traditional uses by the Malays to treat various ailments.

The influences of temperature and naloxone on the antinociceptive activity of Corchorus olitorius L. in mice

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.

The effects of L-arginine, D-arginine, L-name and methylene blue on channa striatus-induced peripheral antinociception in mice

PURPOSE

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.

METHODS

The ASH was prepared by soaking fresh haruan fillet in chloroform:methanol (CM) (2/1 (v/v)) for 72 h followed by evaporation of the upper layer supernatant to remove any solvent residues. The supernatant was then subjected to a freeze-drying process (48 h) followed by doses preparation.

RESULTS

Subcutaneous (SC) administration of ASH alone (0.170, 0.426 and 1.704 mg/kg) exhibited a dose-dependent antinociception. On the other hand, 20 mg/kg (SC) of L-arginine and MB exhibited a significant nociception and antinociception, while D-arginine and L-NAME did not produce any effect at all. Pre-treatment with L-arginine was found to significantly reverse the three respective doses of ASH antinociception; pre-treatment with D-arginine did not produce any significant change in the ASH activity; pre-treatment with L-NAME only significantly increased the 0.170 and 0.426 mg/kg ASH antinociception; and pre-treatment with MB significantly enhanced the respective doses of ASH antinociception, respectively. Furthermore, co-treatment with L-NAME significantly enhanced the L-arginine reversal effect on 0.426 mg/kg ASH antinociception. In addition, MB significantly reversed the L-arginine nociception on 0.426 mg/kg ASH.

CONCLUSIONS

These finding suggest ASH antinociception involves the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway. The presence of NO was found to reverse ASH antinociceptive activity while blocking of cGMP system enhanced it.

Effect of various antagonists on the Channa striatus fillet extract antinociception in mice

The effects of an aqueous supernatant of haruan (ASH) (Channa striatus) fillet extract on various antinociception receptor system activities were examined using a mouse abdominal-constriction model. Mice that were pretreated with distilled water, s.c., followed 10 min later by administration of 25%, 50%, and 100% concentration ASH, s.c., produced a significant concentration-dependent antinociceptive activity (p < 0.001). Pretreatment with naloxone (0.3, 1.0, and 3.0 mg/kg body mass), 10 min before ASH administration, failed to block the extract antinociception. Pretreatment of the 100% concentration ASH with mecamylamine (5 mg/kg), pindolol (10 mg/kg), and haloperidol (1 mg/kg) also did not cause any significant change in its antinociception. However, pretreatment with atropine (5 mg/kg), bicuculline (10 mg/kg), phenoxybenzamine (10mg/kg), and methysergide (5 mg/kg) were found to reverse ASH antinociception. Based on the above findings, the ASH is suggested to contain different types of bioactive compounds that act synergistically on muscarinic, GABAA, α-adrenergic, and serotonergic receptor systems to produce the observed antinocicep tion. Key words: Haruan (Channa striatus), antinociceptive, writhing test, receptor systems