Anxiolytic effect of saponins from Panax quinquefolium in mice

The anxiolytic effect of the saponins from Aniliaeea Panax quinquefolium L. (PQS) was studied in male mice by using a number of experimental paradigms of anxiety and compared with that of the known anxiolytic compound diazepam. Use of the elevated plus-maze test revealed that PQS (50 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) increased the percentage of time and entries spent in open arms. In the light/dark test, PQS (50 and 100 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) prolonged the time spent in the light area. In the hole-board test, PQS (50 and 100 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) significantly increased both head-dip counts and head-dip duration. Both PQS (50 and 100 mg/kg, p.o.) and diazepam (2.5 mg/kg, p.o.) decreased the total fighting time in the isolation-induced aggressive test. Since PQS, in contrast to diazepam, had no effect on locomotion in these tests, its side-effect profile might be considered superior to the benzodiazepines. Thus, the present findings suggest that PQS might be a potential candidate for use as an anxiolytic drug.     

Analgesic and antiinflammatory effects of mollic acid glucoside, a 1 alpha-hydroxycycloartenoid saponin extractive from Combretum molle R. Br. ex G. Don (Combretaceae) leaf

The analgesic and antiinflammatory properties of mollic acid glucoside (MAG), a 1 alpha-hydroxycycloartenoid extract from Combretum molle leaf, have been investigated in mice and rats. The effects of graded doses of mollic acid glucoside (MAG, 5-80 mg/kg i.p.) were examined against thermally- and chemically-induced nociceptive pain in mice. Furthermore, the effects of graded doses of the plant extract (MAG, 5-80 mg/kg p.o.) were also investigated on rat paw oedema induced by subplantar injections of fresh egg albumin (0.5 mg/kg). Morphine (MPN, 10 mg/kg i.p.) and diclofenac (DIC, 100 mg/kg i.p.) were used as reference analgesic and antiinflammatory agents for comparison, respectively. Like DIC (100 mg/kg i.p.) and MPN (10 mg/kg i.p.), MAG (5-80 mg/kg i.p.) produced dose-dependent, significant (p < 0.05-0.001) analgesic effects against thermally and chemically induced nociceptive pain in mice. The extractive (MAG, 5-80 mg/kg i.p.) also significantly reduced (p < 0.05-0.001) rat paw oedema induced by subplantar injections of fresh egg albumin in a dose-related fashion. However, the extract (MAG, 5-80 mg/kg i.p.) was found to be less potent than diclofenac (DIC) as an analgesic or antiinflammatory agent. Experimental evidence obtained from this laboratory animal study indicates that the Combretum molle leaf extractive (MAG) possesses analgesic and antiinflammatory properties, and thus lend pharmacological credence to the folkloric, ethnomedical uses of the plant's leaf in the management, control and/or treatment of painful, arthritic and other inflammatory conditions in some rural communities of southern Africa.     

Evaluation of the analgesic, anti-inflammatory and anti-diabetic properties of Sclerocarya birrea (A. Rich.) Hochst. stem-bark aqueous extract in mice and rats

In order to appraise some of the ethnomedical uses of Sclerocarya birrea (A. Rich.) Hochst., subspecies caffra (Sond.) Kokwaro [family: Anacardiaceae], the present study was undertaken to investigate the analgesic, anti-inflammatory and anti-diabetic properties of the plant's stem-bark aqueous extract in experimental models of pain, inflammation and diabetes mellitus. The analgesic effect of Sclerocarya birrea stem-bark aqueous extract was evaluated in mice, while its anti-inflammatory and anti-diabetic effects were investigated in rats. Diclofenac (DIC, 100 mg/kg p. o.) and chlorpropamide (250 mg/kg p. o.) were used respectively as reference analgesic, anti-inflammatory and anti-diabetic agents for comparison. Like diclofenac (DIC, 100 mg/kg p. o.), Sclerocarya birrea stem-bark aqueous extract (SBE, 100-800 mg/kg p. o.) produced dose-dependent, significant protection (p < 0.05-0.001) against electrical heat-induced pain. The plant extract (SBE, 25-800 mg/kg p. o.) also produced dose- and time-related, sustained and significant reductions (p < 0.05-0.001) in the fresh egg albumin-induced acute inflammation of the rat hind paw oedema. However, the analgesic and anti-inflammatory effects of the plant's extract were found to be approximately 10-15 times less than that of diclofenac. In one set of experiments involving hypoglycaemic/antidiabetic evaluation of the plant's extract, graded doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) were separately administered to groups of fasted normal and fasted diabetic rats. In another set of experiments, a single dose of the plant's aqueous extract (SBE, 800 mg/kg p. o.) was used. The hypoglycaemic effect of this single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) was compared with that of chlorpropamide (250 mg/kg p. o.) in both fasted normal and fasted streptozotocin (STZ)-treated diabetic rats. Following acute treatment, relatively moderate to high doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) produced dose-dependent, significant reductions (p < 0.05-0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. Chlorpropamide (250 mg/kg p. o.) also produced significant reductions (p < 0.05-0.001) in the blood glucose concentrations of the fasted normal and fasted diabetic rats. Administration of the single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) significantly reduced (p < 0.01-0.001) the blood glucose levels of both fasted normal (normoglycaemic) and fasted STZ-treated, diabetic rats. The results of this experimental animal study indicate that Sclerocarya birrea stem-bark aqueous extract possesses analgesic, anti-inflammatory and hypoglycaemic properties. These experimental findings lend pharmacological support to the suggested folkloric uses of the plant's stem-bark in the management and/or control of pain, inflammatory conditions, and adult-onset, type-2 diabetes mellitus in some communities of South Africa.     

Skeletal muscle relaxant action of an aqueous extract of Portulaca oleracea in the rat

The aqueous extract of Portulaca oleracea produced skeletal muscle relaxation in rats following i.p. or oral administration, as assessed by the prolongation of pull-up time. The i.p. route of administration was more effective. When compared with chlordiazepoxide (20 mg/kg, i.p.), diazepam (40 mg/kg, i.p.) and dantrolene sodium (30 mg/kg, oral), the extract (200-1000 mg/kg, i.p.) proved a more effective skeletal muscle relaxant. With 1000 mg/kg i.p., 80% lethality was seen. The LD50 in an acute toxicity test in mice was 1040 mg/kg i.p.     

Neurosedative and muscle-relaxant activities of ethyl acetate extract of Baphia nitida AFZEL

The sedative, anxiolytic and muscle-relaxant effects of the ethyl acetate leaf extract of Baphia nitida (BN) was investigated in intact mice, using the hole-board head-dip test for exploratory behavioural effect, elevated plus maze (EPM) and Y-maze (YM) models of anxiety; chimney, inclined screen, traction and climbing tests for muscle-relaxant effects. In each of these tests, BN (100-400mg/kg, p.o.), diazepam (1mg/kg, i.p.) or distilled water (10ml/kg, p.o.) was administered, 30 or 60min before performing the tests in mice. For exploratory behavioural test, number of head-dip within 15min was counted. For EPM and YM tests, the cumulative time spent in open and closed arms was recorded within 5min. In the muscle-relaxant tests, mice were subjected to modified models such as chimney, inclined screen, traction and climbing tests. BN produced a significant (P<0.05) dose-related decrease in exploratory behaviour in the head-dip test and prolongation of cumulative time spent in open arms of both EPM and YM. BN did not show any significant effect in the chimney and traction tests, but produced significant, dose-dependent muscle relaxation in the inclined screen and climbing tests. Furthermore, BN (200-1200microg/ml) non-competitively shifted the curves of acetylcholine contractions of the toad Rectus abdominis muscle to the right. Oral doses of BN (0.1-20g/kg) did not produce mortality, but the LD(50) when given intraperitoneally, was 645.65mg/kg. Results suggest that the leaf extract of Baphia nitida has sedative, anxiolytic and skeletal muscle-relaxant effects and support its neurosedative use in traditional African medicine.     

Postnatal development and reproductive performance of F1 progeny exposed in utero to an ayurvedic contraceptive: Pippaliyadi yoga

The purpose of this study was to characterize the putative anxiolytic-like activity of an ethanolic extract prepared from the leaves of Apocynum venetum (AV) using the elevated plus maze (EPM) in mice. Male C75BL/6 mice were either treated orally with the AV extract or the positive controls diazepam and buspirone, respectively, 1 h before behavioral evaluation in the EPM. A single treatment of AV extract markedly increased the percentage time spent on and the number of entries into the open arms of the EPM in doses of 30 and 125 mg/kg p.o., respectively. This effect was comparable to that of the benzodiazepine diazepam (1.5 mg/kg p.o.) and the 5-HT_1A agonist buspirone (10 mg/kg p.o.). The effects of AV in 125 mg/kg were effectively antagonized by the benzodiazepine antagonist flumazenil (3 mg/kg i.p.). However, the effects of AV extract could only partially be blocked by the unspecific 5-HT_1A receptor antagonist WAY-100635 (0.5 mg/kg i.p.). Neither diazepam and buspirone nor the AV extract produced any overt behavioral change or motor dysfunction in the open field test. These results indicate that AV extract is an effective anxiolytic agent, and suggest that the anxiolytic-like activities of this plant are mainly mediated via the GABAergic system.     

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.     

Antinociceptive and anti-inflammatory effects of compounds isolated from Scaphyglottis livida and Maxillaria densa

Oral administration of a CH(2)Cl(2)-MeOH (1:1) extract of Scaphyglottis livida produced dose-dependent antinociceptive and anti-inflammatory effects when tested in mice and rats using the hot-plate (150-600 mg/kg) and carrageenan-induced inflammation (150-600 mg/kg) models, respectively. Morphine (1.5-6 mg/kg, p.o.) and indomethacin (10-40 mg/kg, p.o.) were used as positive controls, respectively. Four compounds were isolated from the active extract of Scaphyglottis livida, namely 5alpha-lanosta-24,24-dimethyl-9(11),25-dien-3beta-ol (LDD), 24,24,dimethyl-9,19-cyclolanosta-9(11),25-dien-3-one (cyclobalanone), gigantol and 3,4'-dihydroxy-3',4,5-trimethoxybibenzyl (DTB). LDD and gigantol (25-100 mg/kg, p.o.) significantly increased the hot-plate latency in comparison to vehicle-treated mice and decreased carrageenan-induced inflammation in rats. The antinociception provoked by LDD and gigantol was partially blocked by naloxone (1mg/kg, i.p.). However, pretreatment with L-NAME (100 mg/kg, i.p.) and glibenclamide (10 mg/kg, i.p.) did not affect the antinociceptive response induced by LDD or gigantol suggesting that their pharmacological effect could be partially due to activation of opioid receptors. Moreover, a CH(2)Cl(2)-MeOH (1:1) extract of Maxillaria densa reduced acetic acid-induced abdominal writhes but was not able to produce antinociception in the hot-plate assay. Two compounds were isolated from the active extract of Maxillaria densa, namely fimbriol A and erianthridin. Both compounds partially reduced acetic acid-induced writhes. The results tend to support the popular use of this species in folk medicine for treatment of painful complaints.     

Antinociceptive activity of the methanolic extract of Kaempferia galanga Linn. in experimental animals

Kaempferia galanga Linn. (Zingiberaceae) presents many chemical constituents of the volatile oil extracted from the rhizome. The rhizome of Kaempferia galanga is used by people in many regions for relieving toothache, abdominal pain, muscular swelling and rheumatism. In this study we investigated the antinociceptive activity in mice and rats using acetic acid-induced writhing, formalin, hot plate and tail-flick tests. The extract at test doses of 50, 100 and 200 mg/kg, p.o. clearly demonstrated antinociceptive activity in all tests. This activity was dose- and time-dependent. The extract administered at 200 mg/kg, p.o. had a stronger antinociceptive effect than aspirin (100 mg/kg, p.o.) but less than morphine (5 mg/kg, s.c.). Naloxone (2 mg/kg, i.p.) abolished the antinociceptive action of both morphine (5 mg/kg, s.c.) and the extract (200 mg/kg, p.o.) in a similar manner. In conclusion, the methanol extract of Kaempferia galanga markedly demonstrated the antinociceptive action in experimental animals. The antinociceptive mechanisms appear to be both peripherally and centrally mediated actions and the opioid receptors are probably involved. Therefore, our studies support the use in traditional medicine of Kaempferia galanga against pain caused by various disorders.     

Anticonvulsant activity of Cotyledon orbiculata L. (Crassulaceae) leaf extract in mice

The anticonvulsant activity of Cotyledon orbiculata L. (Crassulaceae) was investigated by studying the effects of both aqueous and methanol extracts of the plant species on seizures induced by pentylenetetrazole, bicuculline, picrotoxin and N-methyl-dl-aspartic in mice. Aqueous extract of Cotyledon orbiculata (50-400mg/kg, i.p.) and methanol extract (100-400mg/kg, i.p.) significantly prolonged the onset of tonic seizures induced by pentylenetetrazole (95mg/kg, i.p.). Methanol extract (400mg/kg, i.p.) also significantly reduced the incidence of the seizures. One hundred to two hundred milligrams/kilogram (i.p.) of aqueous extract of Cotyledon orbiculata significantly delayed the onset of the tonic seizures induced by bicuculline (40mg/kg, i.p.), picrotoxin (12mg/kg, i.p.) and N-methyl-dl-aspartic acid (NMDLA, 400mg/kg, i.p.). Similarly, methanol extract (100-400mg/kg, i.p.) significantly delayed the onset of the tonic seizures induced by bicuculline (40mg/kg, i.p.) and picrotoxin (12mg/kg, i.p.) while 100mg/kg (i.p.) significantly delayed the onset of N-methyl-dl-aspartic acid (NMDLA, 400mg/kg, i.p.)-induced seizures. Methanol extract (200mg/kg, i.p.) significantly reduced the incidence of the seizures induced by bicuculline (40mg/kg, i.p.). Phenobarbitone (12mg/kg, i.p.) and diazepam (0.5mg/kg, i.p.) effectively antagonized only seizures induced by PTZ (95mg/kg, i.p.), bicuculline (40mg/kg, i.p.) and picrotoxin (12mg/kg, i.p.). Phenytoin (30mg/kg, i.p.) did not affect any of the seizures to any significant extent. The data obtained suggest that both aqueous and methanol extracts of Cotyledon orbiculata have anticonvulsant property and may probably be affecting both gabaergic and glutaminergic mechanisms to exert its effect. The phytochemical analysis carried out revealed the presence of cardiac glycosides, saponins, tannins, reducing sugar and triterpene steroids in the plant extract.     

Analgesic and anticonvulsant properties of Tetrapleura tetraptera (Taub) (Fabaceae) fruit aqueous extract in mice

Previous studies in our laboratories and elsewhere have shown that the fruit of Tetrapleura tetraptera (Taub) (family: Fabaceae) is widely used in African traditional medicine for the management and/or control of an array of human ailments, including schistosomiasis, asthma, epilepsy, hypertension and so on. The present study was designed to investigate the analgesic and anticonvulsant effects of Tetrapleura tetraptera (Taub) fruit aqueous extract (TTE) in mice. Morphine (MPN, 10 mg/kg i.p.), diclofenac (DIC, 100 mg/kg i.p.), phenobarbitone (20 mg/kg i.p.) and diazepam (0.5 mg/kg i.p.) were used, respectively, as reference analgesic and anticonvulsant agents for comparison. T. tetraptera fruit aqueous extract (TTE, 50-800 mg/kg i.p.) produced dose-dependent, significant (p < 0.05-0.001) analgesic effects against thermally and chemically induced pain in mice. Like the standard anticonvulsant agents (phenobarbitone and diazepam) used, T. tetraptera fruit aqueous extract (TTE, 50-800 mg/kg i.p.) significantly (p < 0.05-0.001) delayed the onset of, and antagonized, pentylenetetrazole (PTZ)-induced seizures. Aqueous extract of the fruit (TTE, 50-800 mg/kg i.p.) also profoundly antagonized picrotoxin (PCT)-induced seizures, but only partially and weakly antagonized bicuculline (BCL)-induced seizures. However, the results of this experimental animal study indicate that Tetrapleura tetraptera (Taub) fruit aqueous extract (TTE) possesses analgesic and anticonvulsant properties. These findings lend pharmacological support to the suggested folkloric uses of the plant's fruit in the management and/or control of painful, arthritic inflammatory conditions, as well as for the management and/or control of epilepsy and childhood convulsions in some tropical African countries.     

Antinociceptive and anti-inflammatory effects of Tanacetum parthenium L. extract in mice and rats

Oral administration of the feverfew (Tanacetum parthenium) extract led to significant antinociceptive and anti-inflammatory effects against acetic acid-induced writhing in mice and carrageenan-induced paw edema in rats, respectively. These responses were dose-dependent (10, 20, 40 mg/kg, p.o.). Parthenolide (1, 2 mg/kg i.p.), the active constituent of the extract also produced antinociceptive and anti-inflammatory effects. Naloxone (1 mg/kg i.p.), an opiate antagonist, failed to reverse feverfew extract and parthenolide-induced antinociception. Feverfew extract in higher doses (40, 60 mg/kg p.o.) neither altered the locomotor activity nor potentiated the pentobarbitone-induced sleep time in mice. It also did not change the rectal temperature in rats. Feverfew extract exerted antinociceptive and anti-inflammatory effects without altering the normal behaviour of the animals.     

Antinociceptive and anti-inflammatory effects of Satureja hortensis L. extracts and essential oil

Satureja hortensis L. (Lamiaceae) is a medicinal plant used in Iranian folk medicine as muscle and bone pain reliever. In the present study, hydroalcoholic extract, polyphenolic fraction and essential oil of the aerial parts of the herb were prepared and evaluated for the analgesic activity using light tail flick, formalin and acetic acid-induced writhing in mice. Also, the anti-inflammatory effects of the above-mentioned preparations were assessed using carrageenan-induced paw edema in rats. Results showed that in the light tail flick test neither the essential oil nor the extracts could exert any significant effect. The hydroalcoholic extract (2000 mg/kg, p.o.) and the essential oil (200 mg/kg, p.o.) inhibited the mice writhing responses caused by acetic acid. In formalin test, hydroalcoholic extract (500-2000 mg/kg, p.o.), polyphenolic fraction (250-1000 mg/kg, p.o.) and the essential oil (50-200 mg/kg, p.o.) showed analgesic activity and pretreatment with naloxone (1 mg/kg, i.p.) or caffeine (20 mg/kg, i.p.) failed to reverse this antinociceptive activity. Polyphenolic fraction (1000 mg/kg, p.o.) and the essential oil (200 mg/kg) reduced edema caused by carrageenan. These results suggest that S. hortensis L. has antinociceptive and anti-inflammatory effects and probably mechanism(s) other than involvement of opioid and adenosine receptors mediate(s) the antinociception.     

Isolation of hypotensive compounds from Solanum sisymbriifolium Lam

The crude hydroalcoholic root extract (CRE) of Solanum sisymbriifolium Lam. has formerly been shown to have hypotensive activity both in normo-and hypertensive rats. Hypotensive activity-guided fractionation of the CRE was performed in anaesthetized normotensive rats, which led to the isolation of the active principles. The intravenous (i.v.) and intraperitoneal (i.p.) values of the CRE in mice were found to be, respectively, 343 and 451 mg/kg, and no lethal effect was caused by doses up to 5.0 g/kg when administered by oral route. Depression of locomotion, increase of breathing rate and piloerection was observed in a general behavior test with doses up to 200 mg/kg i.p., and 1000 mg/kg p.o., respectively. Increase in the gastrointestinal transit was found using 0.1 g/kg, whereas at doses of 0.5 and 1 g/kg, no significant activity was observed in comparison with the control mice. Hexanic and butanolic fractions induced a remarkable hypotension in anaesthetized normotensive rats in doses of 1, 5, 7.5 and 10 mg/kg i.v. Two compounds isolated from the butanolic fraction induced a significant decrease of the blood pressure, HR, amplitude of the ECG and breathing rate when injected in a dose of 1 mg/kg i.v; and both systofic and diastolic, blood pressures were affected in a proportional mode. The hypotensive effect of the two compounds were not influenced by pretreatment with atropine and propranolol; and the pressor response to noradrenaline was not affected by any of them which suggests that neither a direct muscarinic activity, β-adrenoceptor activation nor decrease of sympathetic vascular tone (sympatholitic activity) are probably involved in the mechanism of hypotension. The present study shows that the CRE of S. sisymbriifolium contains at least two hypotensive compounds whose characterization is under way.     

Possible involvement of GABA A-benzodiazepine receptor in the anxiolytic-like effect induced by Passiflora actinia extracts in mice

Hydroethanol (HE) and methanol (ME) extracts obtained from the leaves of Passiflora actinia Hooker were evaluated for behavioral effects in mice. Single-dose oral administration of HE (300 and 600 mg/kg) or ME (100 and 300 mg/kg) resulted in anxiolytic-like effects in the elevated plus-maze. The anxiolytic-like effects were also seen after the repeated administration of the HE (100 and 300 mg/kg). Flumazenil (10mg/kg, i.p.), a GABA(A)-benzodiazepine receptor antagonist, blocked the effects of ME (300 mg/kg, p.o.) and HE (600 mg/kg). At higher doses, a sedative effect produced by acute administration of HE (600 mg/kg) or ME (300 mg/kg) was indicated by the potentiation of pentobarbital-induced sleep. With regard to memory-disrupting effects of anxiolytics, mice were evaluated by measuring the retest step-down latency 24h after foot-shock in a passive avoidance task. In contrast to diazepam (0.5mg/kg) or piracetam (200mg/kg), ME (30, 100 and 300 mg/kg) or HE (100, 300 and 600 mg/kg) did not influence the step-through latency in the acquisition or retention memory tasks. The present results show an anxiolytic profile for HE and ME of Passiflora actinia. There are also indications of an involvement of GABA(A) system in this effect.     

Effects of Azadirachta indica extract on gastric ulceration and acid secretion in rats

The effect of Azadirachta indica extract on gastric ulceration was studied in albino rats. Azadirachta indica extract (100-800 mg/kg p.o., 100-25 mg/kg i.p.) significantly inhibited gastric ulceration induced by indomethacin (40 mg/kg). Administration of 800 mg/kg p.o. and 250 mg/kg i.p. caused 100% cytoprotection against indomethacin (40mg/kg, i.p.)-induced gastric ulceration. This action was accompanied by a dose-dependent decrease in total gastric acidity. In order to investigate the probable mechanism of Azadirachta indica antiulcer activity, the effect of the extract alone and in combination with histamine (1mg/kg) and cimetidine (0.12 mg/kg) on gastric acid secretion in situ was studied. Azadirachta indica (250 mg/kg) significantly inhibited the basal and histamine-induced gastric acid secretion. Cimetidine seemed to augment Azadirachta indica inhibition of gastric acid secretion.The results suggest that the stem bark extract of Azadirachta indica possesses antiulcer agents, which probably act via histamine H(2) receptor.     

Antinociceptive and anti-inflammatory effects of Thespesia populnea bark extract

The ethanolic extract of Thespesia populnea bark (TPE) was investigated for anti-inflammatory and analgesic activity at the doses (p.o.) of 100, 200 and 400mg/kg body weight. For evaluation of inflammation carrageenan-, histamine- and serotonin-induced paw edema served as acute models and formaldehyde-induced arthritis served as a chronic model in rats. The acetic acid-induced writhing response and formalin-induced paw licking time in the early and late phases of mice were used to assess analgesic activity. The higher doses of TPE (200 and 400mg/kg, p.o.) were inhibiting carrageenan, histamine and serotonin-induced paw edema as well as formaldehyde-induced arthritis successfully. In addition, TPE (200 and 400mg/kg, p.o.) significantly attenuated the writhing responses induced by an intraperitoneal injection of acetic acid and late phase of pain response induced by an subplantar injection of formalin in mice. Furthermore, our phytochemical studies indicated that the ethanolic extract of bark contains alkaloids, carbohydrates, protein, tannins, phenols, flavonoids, gums and mucilage, saponins and terpenes. From acute oral toxicity studies (OECD-423 guidelines), no mortality was observed even at highest dose of TPE (2000mg/kg, p.o.).     

Synergistic effect of methanol extract of Abies webbiana leaves on sleeping time induced by standard sedatives in mice and anti-inflammatory activity of extracts in rats

During the determination of LD50 values of extracts of Abies webbiana, it was observed that the methanol extract (MEAW) produces sedation of animals. This led to investigation of the effect of MEAW on sleeping time in mice. When various doses of the methanol extract (100, 150, and 200 mg/kg body weight) were administered alone, no hypnotic activity was observed. However, these exhibited significant synergistic effects (P < 0.001) at those dose levels in mice when administered prior to the administration of standard sedatives (pentobarbitone sodium: 50 mg/kg and diazepam: 6 mg/kg, respectively). In addition anti-inflammatory effects of methanol, chloroform, and petroleum ether extracts of Abies webbiana leaves in rats were performed to assess scientific validity of the medicinal claim of Indian folk medicine. The effects of leaf extracts (methanol, chloroform, and petroleum ether) against inflammation were studied by carrageenan-induced paw edema model in rats. The methanol extract (400 mg/kg p.o.) of leaves of Abies webbiana showed the best significant anti-inflammatory activity as compared to that of diclofenac sodium (150 mg/kg p.o.). The LD50 values of methanol, chloroform, and petroleum ether extracts were found to be 986, 1387, and > 3200 mg/kg, respectively. Thus, the therapeutic index of methanol extract may be favorable to open a new vista on combination therapy of hypnotics and may also against inflammation.     

Preliminary studies of analgesic and anti-inflammatory properties of Opuntia dillenii aqueous extract

Opuntia dillenii (Ker-Gawl) Haw is a cactus that belongs to the family Opuntiae. Lyophilized aqueous extract of the fruits of the plant, used in Canarian traditional medicine for gastrointestinal and bronchial troubles, was evaluated for analgesic and anti-inflammatory properties in rats and mice. The Opuntia dillenii extract (100-400 mg/kg, i.p.) inhibited, in a dose-related manner, carrageenan-induced paw edema in rats. A dose-dependent action was obtained against chemical (writhing test) and thermic (hot plate test) stimuli, respectively, with doses of 50 and 100 mg/kg.     

Anticonflict actions of aqueous extracts of flowers of Achillea millefolium L. vary according to the estrous cycle phases in Wistar rats

Anticonflict-like effects of aqueous extract of flowers of Achillea millefolium L., a plant with purported anxiolytic actions, were studied in female Wistar rats during late proestrus or diestrus. During late proestrus (p < 0.05), control rats displayed reduced conflict behavior compared with diestrus. Diazepam (2.0 mg/kg; i.p.) reduced conflict behavior both during late proestrus (p < 0.05) or diestrus (p < 0.05). Doses of 8.0 mg/kg (p < 0.05), 10.0 mg/kg (p < 0.05) or 12.0 mg/kg (p < 0.05) of Achillea millefolium reduced conflict behavior during late proestrus. Conversely, during diestrus, only the dose of 12.0 mg/kg (p < 0.05) of Achillea millefolium L. reduced conflict behavior. In conclusion, the anticonflict-like actions of Achillea millefolium L. may vary according to the estrous cycle phase.