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.     

Antinociceptive, anti-inflammatory and antidiabetic effects of Bryophyllum pinnatum (Crassulaceae) leaf aqueous extract

In order to scientifically appraise some of the ethnomedical uses of Bryophyllum pinnatum leaves, the present study was undertaken to investigate the antinociceptive, anti-inflammatory and antidiabetic properties of the plant's leaf aqueous extract in experimental animal models. The antinociceptive effect of the herb's leaf extract was evaluated by the 'hot-plate' and 'acetic acid' test models of pain in mice. The anti-inflammatory and antidiabetic effects of the plant's extract were investigated in rats, using fresh egg albumin-induced pedal (paw) oedema, and streptozotocin (STZ)-induced diabetes mellitus. Diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used respectively as reference drugs for comparison. Bryophyllum pinnatum leaf aqueous extract (BPE, 25-800 mg/kg i.p.) produced significant (P<0.05-0.001) antinociceptive effects against thermally- and chemically-induced nociceptive pain stimuli in mice. The plant extract (BPE, 25-800 mg/kg p.o. or i.p.) also significantly (P<0.05-0.001) inhibited fresh egg albumin-induced acute inflammation and caused significant (P<0.05-0.001) hypoglycaemia in rats. The results of this experimental animal study suggest that Bryophyllum pinnatum leaf aqueous extract possesses antinociceptive, anti-inflammatory and hypoglycaemic properties. The different flavonoids, polyphenols, triterpenoids and other chemical constituents of the herb are speculated to account for the observed antinociceptive, anti-inflammatory and antidiabetic properties of the plant.     

Antinociceptive, anti-inflammatory and antidiabetic properties of Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm ['African Potato'] aqueous extract in mice and rats

In order to scientifically appraise some of the anecdotal, folkloric, ethnomedical uses of Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm ['African Potato'], the present study was undertaken to examine the antinociceptive, anti-inflammatory and antidiabetic properties of the corm's aqueous extract (APE) in mice and rats. The antinociceptive effect of APE was evaluated by 'hot-plate' and 'acetic acid' analgesic test methods in mice; while the anti-inflammatory and antidiabetic effects of the plant's extract were investigated in rats, using fresh egg albumin-induced pedal (paw) oedema, and streptozotocin (STZ)-induced diabetes mellitus models. Morphine (MPN, 10 mg/kg), diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used as reference drugs for comparison. H. hemerocallidea corm aqueous extract (APE, 50-800 mg/kg i.p.) produced dose-dependent, significant (P < 0.05-0.001) antinociceptive effects against thermally- and chemically-induced nociceptive pain stimuli in mice. The plant extract (APE, 50-800 mg/kg p.o.) also significantly (P < 0.05-0.001) inhibited fresh egg albumin-induced acute inflammation, and caused dose-related, significant (P < 0.05-0.001) hypoglycaemia in normal (normoglycaemic) and diabetic rats. The results obtained in this study suggest that the antinociceptive effects of the plant's extract are peripherally- and centrally-mediated. The findings of this experimental animal study indicate that H. hemerocallidea corm aqueous extract (APE) possesses antinociceptive, anti-inflammatory and antidiabetic properties; and thus lend pharmacological support to folkloric, anecdotal uses of 'African Potato' in the treatment and/or management of painful, arthritic inflammatory conditions, as well as in the management and/or control of type-2 diabetes mellitus in some parts of southern Africa.     

Antinociceptive and anti-inflammatory properties from the bulbs of Cipura paludosa Aubl

This study examined the antinociceptive and anti-inflammatory actions of Cipura paludosa Aubl. in several models of inflammatory pain in mice and rats. The ethanolic extract (EE) from Cipura paludosa (1-300mg/kg) given by i.p. and p.o. routes, 30 or 60min earlier, produced a dose-dependent inhibition of the acetic acid-induced pain and Evans blue leakage in mice with ID(50) values of 2.8 and 17.6mg/kg and 17.2 and 176.1mg/kg, respectively. The EE (10mg/kg, i.p.) also inhibited the allodynia (39+/-6%)- and oedema (97+/-6%)-induced by the intraplantar injection of CFA. In addition, the EE (1-30mg/kg, i.p.) inhibited both mechanical and thermal hyperalgesia induced by prostaglandin E(2), PMA and bradykinin in the rat paw, with ID(50) values of 7.3, 12.1 and 4.7 and 13.9, 18.9 and 1.5mg/kg, respectively. These data demonstrate that EE of Cipura paludosa elicited pronounced antinociceptive and anti-inflammatory actions against some models of inflammatory pain in mice and rats. The mechanism by which the extract produced antinociception still remains unclear, but a great part of this effect seems to be related to modulation of the release or action of pro-inflammatory mediators. Moreover, the antinociceptive action demonstrated in the present study supports, at least partly, the ethnomedical uses of this plant.     

Antinociceptive and anti-inflammatory effects of Elaeagnus angustifolia fruit extract

In this study, probable antinociceptive and anti-inflammatory effects of Elaeagnus angustifolia fruit components, were evaluated. For evaluation of antinociceptive effects, the chronic (formalin test) and acute (tail-flick) pain models of rats were used. For the anti-inflammatory effects, the paw inflammation model was used through subcutaneous injection of 5% formalin to the paw of male rats. Water extracts of the fruit and its components in the single dose were assessed through comparison with the antinociceptive and anti-inflammatory effects of sodium salicylate (SS) as a positive control. Administration of 300 mg/kg of SS (i.p.) had no effect on tail flick latency, while 1000 mg/kg of total (i.p. and p.o.) and endocarp (i.p.) extract, increased this latency (P<0.01, P<0.001, respectively), which was not reversed by naloxone (2 mg/kg). In the formalin test, SS (300 mg/kg, i.p.) and the extract (1000 mg/kg, p.o. ) alleviated the animals nociception in the second phase, while in the first phase they were not effective. The total and endocarp extracts (1000 mg/kg, i.p.) showed a significant effect on both phases (P<0.01, P<0.001, respectively) which was also not reversed by naloxone (2 mg/kg, i.p.). In the acute anti-inflammatory test, the total extract and the aqueous extract of individual fruit components showed a significant effect (P<0.001). This anti-inflammatory effect was not significant compared with the anti-inflammatory effect of SS. Because of the extract effect on the tail-flick latency and both phases of the formalin test, the site of its analgesic action is probably central, and the mechanism of antinociceptive action of the extract are not related to the opioid system. Our phytochemical studies indicated that aqueous extract of E. angustifolia fruit contains flavonoids, terpenoids and cardiac glycosides.     

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.     

Evaluation of the Antinociceptive Activity of Ocimum gratissimum L. (Lamiaceae) Essential Oil and its isolated Active Principles in Mice

Ocimum gratissimum is used in popular medicine to treat painful diseases. The antinociceptive properties of O. gratissimum essential oil (OgEO) and two of its active principles (eugenol and myrcene) were tested in classic models of pain (hot plate test and formalin test). Adult male C57BL/6 J mice acutely received corn oil (control group, p.o.), morphine (positive control group, 5 mg/kg, i.p.), OgEO (10, 20, or 40 mg/kg, p.o.), eugenol or myrcene (both at 1, 5, or 10 mg/kg, p.o.). The highest doses of all tested drugs significantly increased the latency to lick the paw(s) in the hot plate test compared with the control group. OgEO at a dose of 40 mg/kg and eugenol and myrcene at a dose of 10 mg/kg were effective in minimizing animal pain in the first and second phases of the formalin test. The antinociceptive effect shown by all drugs tested in hot plate test was reverted by naloxone administration (1 mg/kg), indicating opiod system participation. These results demonstrate the beneficial effects of OgEO and its active principles against neurogenic and inflammatory pain. Our findings demonstrate that OgEO and its isolated active principles exhibited antinociceptive activity in murine pain models. Copyright © 2012 John Wiley & Sons, Ltd.     

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.     

The juice of fresh leaves of Boerhaavia diffusa L. (Nyctaginaceae) markedly reduces pain in mice

The decoction or juice of leaves of Boerhaavia diffusa L. (Nyctaginaceae) is used in Martinican folk medicine for its analgesic and anti-inflammatory properties. In the present investigation we studied the acute oral (p.o.) toxicity of a crude extract obtained from a lyophilized decoction (DE) and from the juice (JE) of fresh leaves. We observed no signs of toxicity up to the dose of 5000 mg/kg (p.o.) in mice. At the dose of 1000 mg/kg, neither extract altered sleeping time evoked by the administration of pentobarbital sodium (i.p.). The DE and JE of B. diffusa were assessed in standard rodent models of algesia and inflammation. We investigated the antinociceptive effect of DE and JE in chemical (acetic acid) and thermal (hot plate) models of hyperalgesia in mice. Dipyrone sodium (200 mg/kg), JE (1000 mg/kg) and DE at the same dose (p.o.), produced a significant inhibition of acetic acid-induced abdominal writhing in mice (100, 50 and 47% inhibition, respectively) when compared with the negative control (P<0.001). In the hot-plate test in mice, morphine and JE produced a significant increase in latency during the observation time. The DE, however, only raised the pain thresholds during the first period (30 min) of observation (P<0.05). The extracts of B. diffusa were also investigated for their anti-edematogenic effect on carrageenan-induced edema in mice. However, neither extract inhibited the paw edema induced in mice (P>0.05). In the acetic acid-induced abdominal writhing in mice, pre-treatment of the animals with naloxone (5 mg/kg, i.p.) significantly reversed the analgesic effect of morphine and JE but not that of DE. These data show that the active antinociceptive principle of B. diffusa is present mainly in the juice of fresh leaves and has a significant antinociceptive effect when assessed in these pain models. The mechanism underlying this analgesic effect of fresh leaves of B. diffusa remains unknown, but seems to be related to interaction with the opioid system.     

Anti-nociceptive and anti-inflammatory activities of the methanolic extract of Parinari polyandra stem bark in rats and mice

The methanolic extract of the stem bark of Parinari polyandra (family Rosaceae) was investigated for possible anti-nociceptive and anti-inflammatory effects in mice and rats. Three models were used to study the extracts effects on nociception which were the acetic acid-induced abdominal constriction test, hot-plate method (both in mice) and the formalin test in rats. The anti-inflammatory effects were investigated employing the albumin-induced hind-paw oedema in rats. Results of the study revealed the extract to have significant (P<0.05) anti-nociceptive effect at a dose of 200 mg/kg p.o. in mice and rats in all the models for anti-nociception while 100 mg/kg p.o. showed significant (P<0.05) effect in the acetic acid-induced abdominal constriction test and in phase I of the formalin test. The extract also exhibited anti-inflammatory effects which were found to be significant (P<0.05) at 200 mg/kg p.o. in the rats tested. Preliminary phytochemical screening of the extract showed the presence of flavonoids, tannins, and saponin glycoside. The results suggest the extract contains pharmacologically active principles. The result is in agreement with the local application of the plant in painful and inflammatory conditions.     

Evaluation of the antinociceptive effect of Rosmarinus officinalis L. using three different experimental models in rodents

The rationale of this investigation was to examine the antinociceptive effect of an ethanol extract of Rosmarinus officinalis (RO) aerial parts, using three different experimental models: acetic acid-induced writhing test and formalin test in mice; and a model of arthritic pain: “pain-induced functional impairment model in the rat (PIFIR model)”. The antinociceptive efficacies were evaluated using several dose–response curves and time courses. The antinociceptive effects from RO extract were compared with the antinociceptive effect of either tramadol (TR: 3.16–50 mg/kg, i.p. in mice, and 1.0–31.62 mg/kg, i.p. in rats) or acetylsalicylic acid (AA: 31.62–562.32 mg/kg, p.o.). RO extract (10–300 mg/kg, p.o.) significantly (P < 0.001) reduced the number of writhing movement induced by the i.p. administration of acetic acid solution in a dose-dependent way (ED₅₀ = 108.84 mg/kg, whereas, TR showed an ED₅₀ = 12.38 mg/kg). In addition, RO extract (30–300 mg/kg) significantly (P < 0.001) inhibited licking and shaking behaviours in both early (neurogenic pain) and in the late (inflammatory pain) phases of the formalin test. These effects were like those produced by TR. Concerning the results using the PIFIR model, RO extract (30–3000 mg/kg, p.o.) like either TR or AA, produced a significant (P < 0.001) and dose-dependent antinociceptive response in rats (RO: ED₅₀ = 222.78 mg/kg versus TR: ED₅₀ = 11.06 mg/kg and AA: ED₅₀ = 206.13 mg/kg). These results strongly suggest that aerial parts of RO possess antinociceptive and anti-inflammatory activity, and reinforce the use of this plant in folk medicine.     

Pharmacological effects of the aqueous extract of Neorautanenia mitis in rodents

The pharmacological effects of the aqueous extract of Neorautanenia mitis (family Papilonaceae) were studied in rodents. Investigations were carried out on acetic acid-induced writhing (pain) in mice and hind paw oedema in rats. The effects of the extract were also studied on the isolated non-pregnant rat uterus and rabbit jejunum. Results showed the extract to possess significant (P<0.05) dose-dependent anti-nociceptive activity between 12.5 and 50.0 mg/kg p.o. in mice and slight anti-inflammatory activity at 25 and 50 mg/kg p.o. in rats. The extract also produced a concentration-dependent inhibition of the normal rhythmic contraction of the isolated non-pregnant rat uterus. It was found to inhibit oxytocin-induced as well as acetylcholine-induced contractions in the rat uterus. The extract also exhibited concentration-dependent inhibition of spontaneous contractions of the rabbit jejunum. Preliminary phytochemical analysis of the extract revealed the presence of saponin glycosides, flavonoids, tannins and alkaloids. The extract had an intraperitoneal (i.p.) LD(50) of 282.84+/-3.2 mg/kg in mice. These data corroborate the traditional use of this plant in the treatment of dysmenorrhea.     

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.     

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.     

Analgesic and antiinflammatory properties of Scoparia dulcis L. Extracts and glutinol in rodents

The analgesic, antiinflammatory and antipyretic activities of the water (WE) and ethanolic (EE) extracts of Scoparia dulcis L. were tested in mice and rats. Both extracts (0.5 and 1 g/kg) p.o., prolonged the sleeping time induced by pentobarbital in mice, EE being more active than WE. Injections of EE (0.5–2 mg/kg i.v.) to anaesthetized rats induced a dose-related hypertension inhibited by alpha-blocker drugs; the hypertension was not obtained after oral treatment. EE (0.25-1 g/kg p.o.) but not WE, reduced writhings induced by acetic acid in mice. Glutinol (30 mg/kg p.o.), a major triterpene obtained from EE, produced the same effect. The tail flick response of mice was not influenced by either extract. EE (0.5 and 1 g/kg) and glutinol (30 mg/kg) p.o., reduced the paw oedema and pleurisy induced by carrageenin in rats, but only EE (1 g/kg) reduced the paw oedema induced by dextran or histamine. No effect of EE was detected on chronic inflammation induced by cotton pellets and in yeast-induced hyperthermia in rats. The results indicate that the extract of S. dulcis is endowed with analgesic effects probably related to the antiinflammatory activity of the plant. Those effects are related mainly to the presence of glutinol and flavonoids, which exert their action on the early phase of the acute inflammatory process.     

Pharmacological evidence favouring the folkloric use of Diospyros mespiliformis Hochst in the relief of pain and fever

The methanol extract of Diospyros mespiliformis was evaluated for its claimed folkloric usage in the relief of pain and fever. Antipyretic, analgesic and anti-inflammatory effects of the extract were evaluated in rats and mice. Studies were carried out on yeast-induced pyrexia in rats, acetic acid-induced writhing in mice, formalin test and egg albumin-induced anti-inflammatory activity in rats. The extract (50 and 100 mg/kg i.p.) gave a potent antipyretic effect for 100 mg/kg and significant activity (P<0.05) against all the analgesic and anti-inflammatory models used. The LD(50) of the extract was estimated to be 513.80+/-33.92 mg/kg i.p. in mice. These results provide support for the use of the plant in relieving pain and fever.     

Antinociceptive effects of Trigonella foenum-graecum leaves extract

There are some reports concerning the antinociceptive effects of the plant Trigonella foenum-graecum (TFG) in Iranian traditional medicine. Because of the side effects of nonsteroidal anti-inflammatory and antinociceptive drugs, and in search for more potent and less harmful compounds, we tried to study the antinocicptive effects of TFG leaves by using tail-flick and formalin tests. Intraperitoneal (i.p.) administration of 500 mg/kg of TFG extract and 100 and 300 mg/kg of sodium salicylate (SS), as a positive control, did not show any effect in the tail-flick test, but the 1000 and 2000 mg/kg of the extract produced significant increase in the tail-flick latency. SS (300 mg/kg, i.p.) induced antinociception in the second phase of the formalin test. TFG (500 mg/kg, i.p.) demonstrated antinociception only in the first phase, but 1000 and 2000 mg/kg, i.p. doses alleviated the pain in both phases. Preliminary LD₅₀ of the extract was very close to 4000 mg/kg, i.p. We conclude that: (1) the extract of TFG leaves produces antinociceptive effects through central and peripheral mechanisms; (2) the antinociceptive effects of 2000 mg/kg of the extract was more potent than 300 mg/kg of SS.     

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.     

Studies on the anti-inflammatory and related pharmacological properties of the aqueous extract of Bridelia ferruginea stem bark

The anti-inflammatory profile of the aqueous extract of Bridelia ferruginea stem bark was investigated using both in vivo and in vitro models. The extract exhibited strong topical anti-inflammatory effect shown as inhibition of croton oil-induced ear oedema in mice, and reduced hind-paw swelling and growth retardation in the adjuvant-induced arthritis model in rats, following oral administration at 10, 20, 40 or 80 mg/kg. The extract (10-80 mg/kg, p.o.) caused an inhibition of increase in vascular permeability in both cyclophosphamide-induced haemorrhagic cystitis and acetic acid-induced vascular permeability in rats and mice, respectively. B. ferruginea produced stabilization of erythrocytes exposed to heat and stress-induced lysis. Antipyretic and analgesic properties of the extract were also observed.     

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.