Studies on antiinflammatory effect of Cassia tora leaf extract (fam. Leguminosae)

The antiinflammatory effect of the methanol extract of the leaves of Cassia tora was investigated against carrageenin, histamine, serotonin and dextran-induced rat hind paw oedema. It exhibited significant antiinflammatory activity against all these agents. The extract (400 mg/kg) showed maximum inhibition of oedema of 40.33%, 31.37%, 53.57% and 29.15% at the end of 3 h with carrageenin, dextran, histamine and serotonin-induced rat paw oedema, respectively. Using a chronic test, the granuloma pouch in rats, the extract exhibited a 48.13% reduction in granuloma weight. © 1998 John Wiley & Sons, Ltd.     

Anti-inflammatory evaluation of Ionidium suffruticosam Ging. in rats

The anti-inflammatory activity of Ionidium suffruticosam (Violaceae) methanol extract was evaluated on carrageenin, histamine and serotonin-induced rat hind paw oedema acute models. The extract at doses of 200 and 400 mg/kg has been found to possess significant anti-inflammatory activity on the tested experimental models. The extract at the dose level of 400 mg/kg exhibited maximum anti-inflammatory activity in all the animal models. In a chronic test, the extract (400 mg/kg) showed 42.78% reduction in granuloma weight. The effect produced by the extract was comparable to that of phenylbutazone, a proto type of a non-steroidal anti-inflammatory agent.     

Anti-inflammatory activity of Trichodesma indicum root extract in experimental animals

The chloroform extract of Trichodesma indicum root has been evaluated for anti-inflammatory activity against oedema produced by carrageenan, dextran, histamine and serotonin, and against formation of granulation tissues by cotton pellet in rats. The effect was compared with the activity of indomethacin, cyperoheptadine and dexamethasone against different types of inflammation. The chloroform extract at doses of 50, 100 and 200 mg/kg exhibited significant (P < 0.001) anti-inflammatory activity in acute and chronic inflammatory models. At 200 mg/kg the chloroform extract showed maximum inhibition of 48.12% in carrageenan-induced rat paw oedema while the standard indomethacin inhibited it by 54.32% after 3 h of carrageenan injection. The chloroform extract (50, 100 and 200 mg/kg) significantly (P < 0.001) and dose-dependently inhibited dextran, histamine and serotonin-induced rat paw oedema compared with control group (vehicle-treated). In the chronic inflammatory model, the chloroform extract (100 and 200 mg/kg) inhibited the granuloma weight by 15.42 and 21.12%, respectively, whereas the indomethacin and dexamethasone inhibited it by 29.29 and 34.13%, respectively. The results obtained suggest marked anti-inflammatory activity of the extract at the dose levels examined.     

Analgesic and anti-inflammatory activity of Crinum glaucum aqueous extract.

The anti-inflammatory and analgesic effects of the aqueous extract of Crinum glaucum were evaluated in mice and rats using the carrageenan- and dextran-induced paw oedema, acetic acid-induced writhing, cold water tail flick and formalin pain tests. The extract (100-400 mg/kg) and acetylsalicylic acid (100 mg/kg) produced a significant (P<0.05) inhibition of the second phase response in the formalin pain model, while only the high dose (400 mg/kg) of the extract showed an antinociceptive effect in the first phase. The extract also showed a dose-dependent inhibition of acetic acid-induced abdominal writhes. The tail flick latency was dose dependently enhanced by the extract but this was significantly (P<0.05) lower than that produced by morphine (2 mg/kg). The extract (125-500 mg/kg) administered 1 h before or after carrageenan-induced paw swelling produced a dose dependent inhibition of the oedema. No effect was observed with the dextran-induced oedema model. The data obtained suggest that the anti-inflammatory and analgesic effects of the extract may be mediated via both peripheral and central mechanisms.     

Pharmacological properties of the methanol extract from Mentha suaveolens Ehrh

The present study analyses the pharmacological activity in in vivo and in vitro models of the methanol extract obtained from the leaves and steams of Menta suaveolens Ehrh. This extract lacked toxicity, but exhibited a central nervous system depressant action; an analgesic effect in models of chemical and mechanical stimulation suggesting the induction of a peripheral analgesic response. The extract also exhibited an antiinflammatory action inhibiting the rat paw oedema induced by carrageenin. Moreover, the in vitro studies showed a significant diminution in the contractile effects induced by histamine, serotonin and acetylcholine.     

Anti-inflammatory, analgesic and antipyretic effects of methanol extract from Bauhinia racemosa stem bark in animal models

In this study, the anti-inflammatory, analgesic, and antipyretic effects of 50, 100 and 200 mg/kg body weight of methanol extract obtained from Bauhinia racemosa stem bark, the so-called MEBR, were investigated. The effects of MEBR on the acute and chronic phases of inflammation were studied in carrageenan, dextran and mediators (histamine and serotonin)-induced paw oedema and cotton pellet-induced granuloma, respectively. Analgesic effect of MEBR was evaluated in acetic acid-induced writhing and hotplate tests. Antipyretic activity of MEBR was evaluated by yeast-induced hyperpyrexia in rats. The anti-oedema effect of MEBR was compared with 10 mg/kg of indomethacin orally. In acute phase of inflammation, a maximum inhibition of 44.9, 43.2, 44.8 and 45.9% (P<0.001) was noted at the dose of 200 mg/kg b.w. after 3h of treatment with MEBR in carrageenan, dextran, histamine and serotonin-induced paw oedema, respectively. Administration of MEBR (200 mg/kg b.w.) and indomethacin (10 mg/kg b.w.) significantly (P<0.05) decreased the formation of granuloma tissue induced by cotton pellet method at a rate of 50.4 and 56.2%, respectively. The extract also inhibited peritoneal leukocyte migration in mice. The MEBR also produced significant (P<0.01) analgesic activity in both models. Further, the MEBR potentiated the morphine- and aspirin-induced analgesic in mice. Treatment with MEBR showed a significant (P<0.01) dose-dependent reduction in pyrexia in rats. The results suggest that MEBR possess potent anti-inflammatory, analgesic and antipyretic activity.     

Anti-inflammatory and antinociceptive activities of extract, fractions and populnoic acid from bark wood of Austroplenckia populnea

Austroplenckia populnea (Reiss) Lund is a Brazilian plant from "cerrado", which belongs to Celastraceae family, popularity know as "marmelinho-do campo, mangabeira-brava, mangabarana, vime and maria-mole". This plant is used in folk medicine to treat dysenteries and inflammatory disorders, such as rheumatism. Austroplenckia populnea bark hydroalcoholic crude extract, and its hexane, chloroform and ethyl acetate fractions, obtained by partition, as well as the isolated populnoic acid were investigated for their anti-inflammatory (carrageenan, dextran and histamine-induced rat paw oedema, histamine-induced increase in vascular permeability, and granulomatous tissue induction) and analgesic activities (writhing and hot plate tests). The ED(50) (oral) of the crude extract for the inhibition of carragenan-induced rat paw oedema assay was determined to be 200 mg/kg, which was also used in the assays with the extract and its fractions in all other experiments. Populnoic acid was administered in the dose of 50 mg/kg. Crude extract, hexane and chloroform fractions (200 mg/kg), and indomethacin (10 mg/kg) inhibited significantly (p<0.05) the formation of the carrageenan-induced rat paw oedema, measured in third hour of experiment (peak of oedema formation) by 43.2%, 37.3%, 31.1% and 59.3%, respectively. There was a significant reduction (p<0.05) in dextran-induced rat paw oedema in all groups, while in the assay using histamine as the oedematogenic agent, only the groups treated with populnoic acid (50 mg/kg) and cyproheptadine (10 mg/kg) displayed significant reduction (p<0.05). The populnoic acid and cyproheptadine reduced the peak of oedema formation (1st hour) by 41.3% and 34.7%, respectively. Only for the groups treated with populnoic acid (50 mg/kg) and cyproheptadine (10 mg/kg) it was observed a significant (p<0.05) reduction in histamine-induced increase in vascular permeability (44.8% and 80.3%, respectively). Granulomatous tissue formation was significantly inhibited (p<0.05) by both hexane fraction (46.0%) and dexamethasone (66.2%). In the analgesic assays, the crude extract and its hexane and chloroform fractions, as well as indomethacin diminished significantly the number of writhings (p<0.05) by 69.6%, 47.2%, 44.8% and 62.8%, respectively. On the other hand, none assayed sample displayed significant result in the hot plate test. Based on the obtained results it is suggested that extracts of Austroplenckia populnea bark and populnoic acid display anti-inflammatory activity, supporting its folkloric use to treat inflammatory disorders.     

Antiinflammatory activity and acute toxicity (LD50) of the juice of Kalanchoe brasiliensis (comb.) leaves picked before and during blooming

Kalanchoe brasiliensis Comb. (Cassulaceae) extracts from leaves picked before and during plant blooming (extracts 1 and 2, respectively) were tested for their antiinflammatory effect on carrageenin‐induced rat paw oedema and for acute toxicity (LD₅₀). Oral doses of 0.25, 0.5 and 1.0 g/kg of extract 1 significantly inhibited the paw oedema during the first 4 h after injection of 2% carrageenin, while oral doses of 0.5, 1.0 and 2.0 g/kg of extract 2 had no inhibitory activity on the paw oedema induced by carrageenin. The results indicate an antiinflammatory effect of extract 1 and a proinflammatory effect of extract 2. K. brasiliensis extracts 1 and 2 presented no acute toxicity on mice at the doses of 0.25 to 5 g/kg administered intraperitoneally. Copyright © 1999 John Wiley & Sons, Ltd.     

Evaluation of anti-inflammatory activity of Cissampelos pareira root in rats

In the present study, 50% ethanolic extract of Cissampelos pareira roots (CPE) in acute, subacute and chronic models of inflammation was assessed in rats. Per os (p.o.) administration of CPE (200, 400 mg/kg) exhibited significant anti-inflammatory activity. In acute inflammation as produced by carrageenin 59.55% and 64.04%, by histamine 15.38% and 30.77%, by 5-hydroxytryptamine 17.78% and 31.11% and by prostaglandin E₂-induced hind paw edema 19.23% and 30.77% protection was observed. While in subacute anti-inflammatory models using formaldehyde-induced hind paw edema (after 1.5 h) 38.36% and 47.95% and in chronic anti-inflammatory model using cotton pellet granuloma 15.02% and 19.19% protection from inflammation was observed. CPE did not show any sign of toxicity and mortality up to a dose level of 1000 mg/kg, p.o. in rats. Both acute as well as chronic administration of CPE (100, 200 and 400 mg/kg, p.o.) did not produce any gastric lesion in rats. These data indicate that CPE possesses significant anti-inflammatory activity without ulcerogenic activity suggesting its potential as an anti-inflammatory agent for use in the treatment of various inflammatory diseases.     

Effect of aqueous extract of Tragia involucrata Linn. on acute and subacute inflammation

Antiinflammatory activity of aqueous extract of Tragia involucrata was tested on carrageenan-induced hind paw oedema and cotton pellet granuloma models in albino rats. In the subacute model, cotton pellet granuloma was produced by implantation of 10 mg sterile cotton in the axilla under ether anaesthesia. The animals were administered an aqueous extract at various concentrations of 50, 100, 200, 300 and 400 mg/kg. Phenyl butazone (80 mg/kg) was used as a standard drug. The paw diameter was measured at different time intervals and the dry granuloma weight was taken after the treatment. The aqueous leaf extract (400 mg/kg) showed the maximum inhibition (84.23%) of oedema at the end of 3 h following carrageenin-induced rat paw oedema. In subacute inflammation, the extract showed 76.25% reduction in granuloma weight. The results prove that the aqueous leaf extract showed highest antiinflammatory activity in acute and subacute inflammation and also support the usage of traditional claims.     

Anti-inflammatory activity of Markhamia tomentosa (Benth.) K. Schum. Ex Engl. ethanolic leaf extract

Ethnopharmacological relevance

The leaves of Markhamia tomentosa (Benth.) K. Schum (Bignoniaceae) are used traditionally for the treatment of oedema and rheumatoid arthritis in Nigeria.

Aim of the study

The aim of the work was to investigate the anti-inflammatory activity of the ethanolic leaf extract of Markhamia tomentosa.

Materials and methods

The extract was screened using the carrageenan-induced paw oedema in rats, xylene-induced oedema in mice and the formalin-induced oedema in mice at 50, 100, 200 mg/kg doses p.o respectively. The mechanism by which the extract mediated the anti-inflammatory activity was assessed using the histamine-induced rat paw oedema and serotonin-induced rat paw oedema at the highest dose (200 mg/kg).

Results

The results showed that the extract produced a significant dose-dependent inhibition in carrageenan-induced, xylene-induced and the formalin tests. The extract exerted a significant inhibition of 54.55% (P<0.0001) and 42.11% (P<0.01) at 90 min in the histamine-induced and serotonin-induced rat paw oedema models respectively.

Conclusions

These findings suggest that the ethanolic leaf extract of Markhamia tomentosa possesses anti-inflammatory activity possibly mediated by histamine. The results justify the use of the plant in the preparation of ethno medicines used in the treatment of ailments associated with inflammation.     

Anti-inflammatory effect of O-methylated flavonol 2-(3,4-dihydroxy-phenyl)-3,5-dihydroxy-7-methoxy-chromen-4-one obtained from Cassia sophera Linn in rats

Ethnopharmacological relevance

Cassia sophera Linn (Family Caesalpiniaceae), popularly known as kasundi, is used both in the Indian traditional system and folk medicine to treat several inflammatory pathologies such as asthma, arthritis and pains. The aim of the present study was to evaluate the scientific basis of anti-inflammatory activity of Cassia sophera ethanol extracts and of an isolated constituent of Cassia sophera.

Materials and methods

The anti-inflammatory activity of Cassia sophera was studied using the carrageenan, dextran induced rat paw edema, and cotton pellet induced granuloma in rats. The ethanol extract was administered at the concentrations of 200 and 400 mg/kg body weight whereas rhamnetin (RN) was administered at a dose of 10 and 15 mg/kg, b.w. Indomethacin was used as standard drug.

Results

The HPLC analysis revealed that good amounts of rhamnetin (0.18%) was present in Cassia sophera.The ethanol extracts at 400 mg/kg, showed maximum inhibition of inflammation induced by carrageenan (44%), dextran (40%), cotton pellets (37.47%). On the other hand rhamnetin (15 mg/kg) exhibited maximum anti-inflammatory effect, that is 79 and 33% at the end of 3 h with carrageenin, and dextran-induced rat paw edema, respectively. In a chronic test rhamnetin (15 mg/kg) showed 43.32% reduction in granuloma weight.

Conclusion

The marked inhibitory effect on paw edema and granuloma showed that Cassia sophera possess remarkable anti-inflammatory activity which may be due to rhamnetin at least in part, supporting the folkloric usage of the plant to treat various inflammatory diseases.     

Anti-inflammatory and anti-nociceptive activities of the stem bark extracts from Allanblackia monticola STANER L.C. (Guttiferae)

THE AIM OF THIS STUDY: was to assess the anti-inflammatory and mechanism of action of Allanblackia monticola (Guttiferae). The anti-inflammatory activity "in vivo" of the methylene chloride/methanol extract, methanol and methylene chloride fractions of stem barks of Allanblackia monticola, administered orally at doses of 37.5; 75; 150 and 300 mg/kg, was evaluated on carrageenan-induced oedema in rats to determine the most active fraction. Indomethacin, inhibitor of cyclo-oxygenase was used as reference drug. The effects of the most active fraction were then examined on the rat paw oedema caused by histamine, serotonin, arachidonic acid and dextran followed by its ulcerogenic effect. The results showed that the methylene chloride fraction of Allanblackia monticola was more effective on the oedema caused by the carrageenan. The anti-nociceptive activity of the methylene chloride fraction was assessed using the acetic acid-induced abdominal constriction model, formalin test and hot plate test. At 150 mg/kg, Allanblackia monticola caused maximum inhibitions of inflammation induced by carrageenan (83.33%), by histamine (42.10%), by dextran (40.29%) and by arachidonic acid (64.28%). Allanblackia monticola (75-300 mg/kg) did not cause significant modification of the oedema induced by serotonin. Concerning the anti-nociceptive properties of the plant, the methylene chloride fraction (75-300 mg/kg) caused a dose-dependent inhibition on abdominal contractions induced by acetic acid (32.34-77.37%) and significantly inhibited the inflammatory pain caused by formalin (40.71-64.78%). Allanblackia monticola did not increase the latency time in the hot plate test. Like indomethacin (10mg/kg), the fraction at the dose of 150 mg/kg caused ulceration of the gastric mucous membrane in treated rats. These results show that Allanblackia monticola has an anti-inflammatory and analgesic activities with gastric ulcerative side effects.     

Inhibition of chemically induced inflammation and pain by orally and topically administered leaf extract of Manihot esculenta Crantz in rodents

The aqueous leaf extract of Manihot esculenta Crantz (MELE) is being used orally and topically in traditional African medicine for the treatment of inflammation and pain, and claimed to be safe. The anti-inflammatory effects of MELE (100-400mg/kg, p.o. or 1-4%, w/w in petroleum jelly, topically) were tested against carrageenan-induced paw oedema in rats as well as against xylene-induced ear oedema in mice. The analgesic effect of MELE (100-400mg/kg, p.o. or 1-4%, w/w in petroleum jelly, topically) was tested against acetic acid-induced (20mul, 0.6%, v/v in normal saline, i.p.) and acetylcholine-induced (8.3mg/kg, i.p.) mouse writhing models. At 100-400mg/kg, p.o. and 1-4% (w/w), topically, MELE produced significant inhibitions of carrageenan-induced rat paw oedema and xylene-induced ear swelling in mice. Effects produced by MELE were significantly higher than those produced by indomethacin (10mg/kg, s.c. or 1%, w/w in petroleum jelly) in the anti-inflammatory models. For the analgesic effect, MELE (100-400mg/kg, orally) and (1-4%, w/w, topically), like aspirin (100mg/kg, i.p.) exhibited significant (P<0.05) inhibition of acetic acid- and acetylcholine-induced mouse writhing tests, compared to untreated control. Effects produced by MELE were significantly lower than those produced by aspirin (100mg/kg, i.p.) in the analgesic models, except for the topically administered extract on acetylcholine-induced pain. Acute oral administration up to 10g/kg did not cause death within 14 days, but mortalities were produced in i.p. administered extract with LD(50) of 2.5+/-0.3g/kg. Based on these, the extract may contain orally safe, topically and orally effective anti-inflammatory and analgesic principles, which justify its use in traditional African medicine.     

Anti-inflammatory and anti-nociceptive activities of Sipunculus nudus L. extract

Ethnopharmacological relevance

Sipunculus nudus has long been employed as traditional Chinese medicine in folk remedies for the treatment of carbuncles, tuberculosis and nocturia, regulating the functions of stomach and spleen, as well as for the restoration to health in debilities caused by various pathogens and aging. Decoction of Sipunculus nudus has traditionally been used to remedy sternalgia in folk medicine.

Aim of the study

This study aimed to assess the anti-inflammatory and anti-nociceptive activity of the water extract from Sipunculus nudus.

Materials and methods

The water extract from the body wall of Sipunculus nudus was obtained with the yield of 14.1%. The anti-inflammatory effect in six animal models and anti-nociceptive effect in two animal models of the water extract were evaluated by oral for the study.

Results

Pretreatment with the extract (at the dose of 50, 100 and 200 mg/kg) produced significant dose-dependent anti-inflammatory and anti-nociceptive effects. At 200 mg/kg dose, the inhibition ratio of the extract on carrageenan-induced rat hind paw oedema, dextran-induced rat paw oedema, cotton pellet granuloma in rats, carrageenan-induced peritonitis and acetic acid-induced vascular permeability were 59.2%, 51.0%, 53.1%, 42.5%, 50.8%, better than that of indomethacin (5 mg/kg) 49.5%, 50%, 44.4%, 37.6%, 46.8%, respectively. The inhibition ratio of the extract (200 mg/kg dose) on xylene-induced mouse ear oedema was 61.5%, lower than 63.7% for indomethacin (5 mg/kg). At 200 mg/kg, the extract decreased number of writhing 52.3% in acetic acid-induced writhing model and increased the response latency 25.24% in hot plate test.

Conclusions

The water extract from the body wall of Sipunculus nudus possesses excellent anti-inflammatory activity as well as peripheral and central analgesic properties.     

Anti-inflammatory and analgesic activity of Peperomia pellucida (L.) HBK (Piperaceae)

An aqueous extract of the aerial part of Peperomia pellucida (L.) HBK (Piperaceae) was tested for anti-inflammatory (paw edema induced by carrageenin and arachidonic acid) and analgesic activity (abdominal writhes and hot plate) in rats and mice, respectively. Oral administration of 200 and 400 mg/kg of the aqueous extract exhibited an anti-inflammatory activity in the carrageenin test, which was based on interference with prostaglandin synthesis, as confirmed by the arachidonic acid test. In the abdominal writhing test induced by acetic acid, 400 mg/kg of the plant extract had the highest analgesic activity, whereas in the hot-plate test the best dose was 100 mg/kg. The LD(50) showed that Peperomia pellucida (5000 mg/kg) presented low toxicity.     

Effects of the aqueous extract of Bridelia ferruginea stem bark on carrageenan-induced oedema and granuloma tissue formation in rats and mice.

The anti-inflammatory activity of the aqueous extract of the stem bark of Bridelia ferruginea was evaluated using carrageenan-induced paw oedema in rats and mice, and the cotton pellet granuloma method. The extract at doses ranging from 10 to 80 mg/kg p.o. significantly inhibited the carrageenan-induced rat paw oedema, with an ID50 value of 36 mg/kg. However, a low activity was produced in the mouse paw oedema. The extract also suppressed the granulomatous tissue formation of chronic inflammation. B. ferruginea therefore proved to be effective in both the acute and chronic phases of the inflammatory process.     

Analgesic and antiinflammatory activities of Ageratum conyzoides in rats

The water soluble fraction (WSF) obtained from a hydroalcohol extract of A. conyzoides, a medicinal plant used in Brazilian folk medicine, was evaluated for possible analgesic and antiinflammatory activities. It was demonstrated that WSF (20–50 mg/kg; i.p.) treatment reduced the articular incapacitation induced by carrageenin (300 μg) in rats. In this model, naloxone (2 mg/kg) blocked the analgesic action of morphine (2 mg/kg) but did not change the WSF antinociceptive effect. It suggests that endogenous opioids are not involved in the WSF antinociceptive effect. The neutrophil migration induced by carrageenin (300 μg) injection into rat peritoneal cavities and into 6-day-old subcutaneous air-pouches was significantly inhibited (p <0.05) by WSF pre-treatment (30 and 50 mg/kg; s.c.). At the same dose WSF also inhibited (p <0.05) the carrageenin (400 μg/paw)-induced oedema, but failed to modify the oedema induced by dextran (100 μg/paw). Furthermore, the increase in the cutaneous vascular permeability induced by the potent leukocyte chemotactic agent LTB₄ (39 ng co-injected with 500 ng iloprost, i.d.) was significantly blocked by WSF (30 mg/kg; i.p.). However, in the same dose WSF caused a 2-fold increase in the vascular permeability induced by histamine (10 μg), a direct vasoactive mediator. These results suggest that WSF can inhibit the inflammatory reactions induced by neutrophil mobilizing stimuli. © 1997 John Wiley & Sons, Ltd.     

Anti-nociceptive and anti-inflammatory properties of Caralluma arabica

In the present study, a 10% ethanolic extract of Caralluma arabica at the doses of 200 and 400 mg/kg was evaluated for the antinociceptive activity using the hot plate and acetic acid induced abdominal constrictions in mice and tail flick method in rats. Oral and topical application of C. arabica extract was assessed in the present study for anti-inflammatory properties using carrageenan-induced rat paw oedema. Anti-inflammatory activity was also evaluated using cotton pellet granuloma method. C. arabica extract showed significant Anti-nociceptive properties in all the models studied. C. arabica extract significantly reduced the increase in hind paw volume induced by carrageenan injection when used orally or topically. Results of the present study confirm the use of C. arabica traditionally for the treatment of painful and inflammatory conditions and indicate transdermal absorption of the plant extract.     

Antinociceptive and antiedematogenic effects of the aqueous extract of Hyptis pectinata leaves in experimental animals

The aqueous leaf extract of Hyptis pectinata (L.) Poit (Lamiaceae), popularly known in Brazil as "sambaicatá" or "canudinho", was tested for its antinociceptive effects using the abdominal writhing, hot plate and formalin test models, and for its aniedematogenic effects using the carrageenin and arachidonic acid-induced rat paw edema. The aqueous extract of Hyptis pectinata administered orally at doses of 100, 200 and 400 mg/kg had a significant antinociceptive effect in the test of acetic acid-induced abdominal writhing, with 43, 51 and 54% reduction of writhes, respectively, compared to the control. An increase in hot-plate latency of 47 and 37.5% was also observed in animals receiving doses of 200 and 400 mg/kg, p.o. when placed on a hot plate. In the formalin test, doses of 200 and 400 mg/kg, p.o. had no significant effect during the first phase of the test (0-5 min), while the dose of 200 mg/kg, p.o. reduced the nociceptive effect by 70% during the second phase (20-25 min). At the dose of 600 mg/kg, p.o., the aqueous extract inhibited carrageenin-induced rat paw edema by 34.1%, and the dose of 300 mg/kg administered intraperitoneally inhibited the rat paw edema induced by subplantar injection of arachidonic acid by 32.8%. These results suggest that the aqueous extract from the Hyptis pectinata leaves produces antiedematogenic and antinociceptive effects. The antinocipetion observed with the hot-plate test probably involves the participation of the opioid system.