Probable role of spinal purinoceptors in the analgesic effect of Trigonella foenum (TFG) leaves extract

In our previous work, we demonstrated that Trigonella foenum (TFG) leaves extract can exert analgesic effects in both formalin (F.T.) and tail flick (T.F.) tests. Spinal serotonergic system, but not endogenous opioid system, was involved in TFG induced analgesia (in the second phase of formalin test). Some reports concern the similarity between NSAIDs and TFG extract in many pharmacological effects or the interaction between NSAIDs and purinergic system; so the present study was designed to investigate the relationship between TFG extract and purinergic system or the inhibition of cyclo-oxygenase (COX). We examined the effect of TFG extract on: (1) the response of rabbit platelets to ADP induced aggregation, (2) the contraction of mouse vas deferens induced by alpha,beta-Me-ATP (a P(2) receptor agonist; this receptor mediates the rapid phase of ADP- and ATP-evoked influx of Ca(2+) through a non-specific cation channel in platelets), (3) alpha,beta-Me-ATP induced hyperalgesia in tail flick test in male rats and (4) the specific inhibition of COX-1 and COX-2. Our results showed that TFG extract (0.5, 1, 1.5, 3 mg/ml) inhibited ADP (10(-5) mol) induced platelet aggregation (IC(50)=1.28 mg/ml). alpha,beta-Me-ATP (30 microM) induced isometric contraction in vas deferens while suramin (a P(2) receptor antagonist, 50, 150, 300 microM) or TFG extract (0.5, 1, 2, 3 mg/ml) inhibited this effect significantly (IC(50) were 91.07 microM and 1.57 mg/ml, respectively). Moreover, alpha,beta-Me-ATP (3 microg/rat, i.t.) induced hyperalgesia in tail flick test, but it was prevented by co-injection of alpha,beta-Me-ATP with suramin (120 microg/rat, i.t.) or TFG extract (1mg/rat, i.t.). Effective concentrations of TFG extract in the above mentioned experiments did not inhibit COX enzymes in EIA tests. In conclusion, these results indicate that the blocking of spinal purinoceptors may contribute in the analgesic effect of TFG leaves extract.     

Anti-inflammatory and antipyretic effects of Trigonella foenum-graecum leaves extract in the rat

Anti-inflammatory and antipyretic effects of the Trigonella foenum-graecum (TFG) leaves extract, an Iranian medicinal plant, were examined. For anti-inflammatory activity, the formalin-induced edema model was used. Hyperthermia was induced by intraperitoneal injection of 20% (w/v) aqueous suspension of brewer's yeast. Sodium salicylate (SS) was used as a positive control. Both TFG and SS significantly reduced formalin-induced edema in single dose (TFG 1000 and 2000 mg/kg, SS 300 mg/kg) and chronic administration (TFG 1000 mg/kg and SS 300 mg/kg). TFG and SS also significantly reduced hyperthermia induced by brewer's yeast in 1 and 2 h after their administration. The results indicate that the TFG leaves extract possess anti-inflammatory as well as antipyretic properties in both i.p. and p.o. administration. Phytochemical studies indicate that alkaloids, cardiac glycosides, and phenols are the major component in the extract. Although existence of three anti-inflammatory, analgesic and antipyretic effects in this extract suggest a NSAID-like mechanism for it, but the presence of alkaloids, the absence of other effective compounds such as flavonoids, saponins, steroids, etc., and also its analgesic effect on tail-flick test that usually is not produced by NSAIDs, suggest another mechanism for the extract. So the possibility of alkaloids as effective compounds, in this extract, increases.     

Anti-inflammatory and analgesic activity of Biebersteinia multifida DC. root extract

The root of Biebersteinia multifida DC (Geraniaceae), a native plant of Iran, has been used topically for the treatment of musculoskeletal disorders as a folk medicine. The anti-inflammatory and analgesic effects of the root extract were studied using carrageenan induced edema and formalin tests. A similar activity was seen between Biebersteinia multifida root extract (10 mg/kg; i.p.) and indomethacin (4 mg/kg; i.p.) in carrageenan test. The results of formalin test showed the analgesic activity of the root extract (50 mg/kg; i.p.) was comparable with morphine (10 mg/kg; i.p.) at the first phase of formalin test. Furthermore, the probable ulcerogenic activity of the root extract was also studied. The extract did not show any ulcerogenic effect at anti-inflammatory doses (10 mg/kg; p.o.).     

Evaluation of the analgesic effect of Echium amoenum Fisch & C.A. Mey. extract in mice: possible mechanism involved

Echium amoenum Fisch & C.A. Mey. has been used in Iranian traditional medicine as demulcent and analgesic in common cold from long ago. In this investigation, the analgesic effect of the methanolic extract of the petals of this plant on male albino mice was evaluated by formalin and hot-plate test. The methanolic percolated extract with different doses 5, 10, 20 and 30 mg/kg were injected intraperitoneally to mice. The results showed that the dose of 10 mg/kg of extract had the highest analgesia in formalin (P<0.05) and hot-plate test (P<0.01) compared to the control group. The analgesic effect of extract was lower than morphine 2.5 mg/kg and ASA 300 mg/kg in the chronic phase of pain in formalin test (P<0.05) and in hot-plate test too (P<0.05). Pretreatment of animal with naloxone 4 mg/kg, s.c. 5 min before extract, decreased the analgesia induced by extract in hot-plate and acute phase of formalin tests; therefore, the opioid receptor may be involved at least partly in the analgesic effect of Echium amoenum extract. The results suggested that Echium amoenum extract has a suitable analgesic effect and further studies are required to evaluate these effects and the potential of the plant.     

Evaluation of the oral hypoglycaemic effect of Trigonella foenum-graecum L. (methi) in normal mice

Trigonella foenum-graecum (Fenugreek) (Leguminosae) is employed as a herbal medicine. Its seeds are known for their carminative, tonic and antidiabetic effects. A curative dose of Trigonella foenum-graecum also produces antiulcer action. In this study we have investigated the hypoglycaemic activities of the aqueous extract of the seeds Trigonella foenum-graecum in normal mice using oral route of adminstration. The methanolic extract administered through the same route produced hypoglycaemic effect only at the dose of 1 g/kg body weight. The aqueous extract is under further investigation to determine the chemical structure of the active component. The presence of hypoglycaemic activity in aqueous and methanolic extract indicates that the active compounds are polar in nature.     

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.     

Antinociceptive activity of Syzygium jambos leaves extract on rats

Syzygium jambos (L.) Alston (Myrtaceae) (syn Eugenia jambos) is a widespread medicinal plant traditionally used in sub-Saharan Africa to treat several diseases. The analgesic potential of leaf hydro-alcoholic extracts was assessed in rats. Hot plate and formalin tests were used to estimate cutaneous nociception whereas measurements of forelimb grip force were done to assess muscular nociception under normal and inflammatory conditions. In the hot plate test, Syzygium jambos extract produced a significant increase in the withdrawal response latencies in a dose-dependant manner (10-300 mg/kg i.p.) and with a maximal effect (analgesic efficacy) similar to that of morphine. The extract (100-300 mg/kg i.p.) significantly reduced pain scores in all the phases of the formalin test with an analgesic efficacy higher than that shown by diclofenac. Although the extract (300 mg/kg) did not alter grip force in intact rats, it reversed the reduction in grip force induced by bilateral injection carrageenan in the forelimb triceps. This analgesic effect of the extract on muscle hyperalgesia was not antagonized, but enhanced, by naloxone. Thus, the Syzygium jambos extract has remarkable analgesic effects on both cutaneous and deep muscle pain that is not mediated by opioid receptors.     

Evaluation of the analgesic effect of alkaloid extract of Peganum harmala L.: possible mechanisms involved

The seeds of Peganum harmala L. (Pgh) (Zygophyllaceae) have been used in Moroccan traditional medicine for treatment of a various diseases and to relieve dolorous process. The major objective of this paper was to investigate the mechanism of the analgesia induced by alkaloid extract of Peganum harmala. In the present work, the antinociceptive action was assayed in several experimental models in mice: writhing, formalin, and hot plate tests. The alkaloid extract (12.5 and 25mg/kg) and in a dose-dependent manner significantly reduced the nociception by acetic acid intraperitoneal injection (p<0.001). In the formalin test, the extract also significantly reduced the painful stimulus in both phases of the test (p<0.001). Treatment with the extract when given by (i.p. or i.c.v.) or with morphine (10mg/kg, i.p.) produced a significant increase of the reaction time in hot plate test. These result showed that the alkaloid extract of Pgh contains active analgesic principles acting both centrally and peripherally. Furthermore, this antinociceptive effect has been avoided by naloxone at a dose of 1mg/kg in the first phase of formalin and hot plate tests indicating that this extract act partly through an opioid-mediated mechanism. In conclusion, the alkaloid extract of Peganum harmala seems to have both central and peripheral antinociceptive activities which may be mediated by opioid receptors.     

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 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 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.     

Olive (Olea europaea L.) leaf extract elicits antinociceptive activity, potentiates morphine analgesia and suppresses morphine hyperalgesia in rats

Aim of the study

Olive (Olea europaea) leaves are used as anti-rheumatic, anti-inflammatory, antinociceptive, antipyretic, vasodilatory, hypotensive, antidiuretic and hypoglycemic agents in traditional medicine. Recently, it has been shown that olive leaf extract (OLE) has calcium channel blocker property; however, its influences on nociceptive threshold and morphine effects have not yet been clarified.

Materials and methods

All experiments were carried out on male Wistar rats. The tail-flick, hot-plate and formalin tests were used to assess the effect of OLE on nociceptive threshold. To determine the effect of OLE on analgesic and hyperalgesic effects of morphine, OLE (6, 12 and 25 mg/kg i.p.) that had no significant nociceptive effect, was injected concomitant with morphine (5 mg/kg and 1 μg/kg i.p., respectively). The tail-flick test was used to assess the effect of OLE on anti- and pro-nociceptive effects of morphine.

Results

The data showed that OLE (50-200 mg/kg i.p.) could produce dose-dependent analgesic effect on tail-flick and hot-plate tests. Administration of 200 mg/kg OLE (i.p.) caused significant decrease in pain responses in the first and the second phases of formalin test. In addition, OLE could potentiate the antinociceptive effect of 5 mg/kg morphine and block low-dose morphine-induced hyperalgesia.

Conclusion

Our results indicate that olive leaf extract has analgesic property in several models of pain and useful influence on morphine analgesia in rats. Therefore, it can be used for the treatment and/or management of painful conditions.     

Anti-inflammatory,analgesic activity and acute toxicity of Glaucium grandiflorum extract

The species of Glaucium have been used in Iranian herbal medicine as laxative, hypnotic, antidiabetic agents and also in the treatment of dermatitis. The anti-inflammatory and analgesic effects of the aerial parts of Glaucium grandiflorum Boiss & Huet (Papaveraceae), a native plant of Iran, were studied using carrageenan induced edema, formalin and hot plate tests. The G. grandiflorum extract at the dose of 200 mg/kg had more edema inhibition than indomethacin at the doses of 10 (P<0.01) and 8 mg/kg (P<0.001) in the carrageenan test. The ED₅₀ (i.p.) in the edema induced by carrageenan was 13.59 mg/kg. In formalin test, the extract (60–90 mg/kg, i.p.) caused graded inhibition of both phases of formalin-induced pain. In hot plate test, the i.p. administration of the extract at the doses of 60, 70, 80 and 90 mg/kg significantly raised the pain threshold at a observation time of 45 min in comparison with control (P<0.001). The extract, at the antinociceptive doses, did not affect motor coordination of animals when assessed in the rotarod model. The 72 h acute LD₅₀ value of this extract after i.p. administration in mice was 797.94 mg/kg.     

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.     

5-羟色胺和生长抑素对P物质及慢痛引起的脊髓背角神经元电活动的影响

本研究用多管微电极细胞外记录和离子微电泳方法，以Wistar大鼠为实验对象，观察了P物质（SP）对脊髓背角神经元自发放电和慢性伤害性痛放电的影响以及与5-羟色胺（5－HT）和生长抑素（SOM）的关系。结果表明：（1）电泳SP可使脊髓背角神经元单位放电增多。（2）电泳SP又可抑制福尔马林（Formalin）引起的神经元慢性伤害性痛放电。（3）电泳5－HT和SOM可抑制SP及慢痛诱发的脊髓背角神经元放电。上述结果提示：在痛觉调制过程中，脊髓内SP起着传递痛觉信息和镇痛的双重作用，5－HT和SOM可通过抑制SP的效应，参与痛觉调制。     

Analgesic, antiinflammatory and antidiabetic properties of Harpagophytum procumbens DC (Pedaliaceae) secondary root aqueous extract

South Africa is blessed with a rich floral biodiversity of medicinally useful plants. One such plant is Harpagophytum procumbens DC (Family: Pedaliaceae). H. procumbens is widely used in South African traditional medicine for the treatment, management and/or control of a variety of human ailments. In the present study, the analgesic effect of H. procumbens secondary root aqueous extract was evaluated in mice, using the 'hot-plate' and 'acetic acid' test methods; while the antiinflammatory and antidiabetic effects of the plant's secondary root extract were investigated in rats. Fresh egg albumin-induced pedal oedema and streptozotocin (STZ)-induced diabetes mellitus were used as experimental test models of inflammation and diabetes Diclofenac (DIC, 100 mg/kg i.p.) was used as a reference analgesic and antiinflammatory agent for comparison. Chlorpropamide (250 mg/kg p.o.) was used as a reference hypoglycaemic agent for comparison. H. procumbens root aqueous extract (HPE, 50-800 mg/kg i.p.) produced significant (p < 0.05-0.001) analgesic effects against thermally and chemically induced nociceptive pain stimuli in mice. H. procumbens root extract (HPE, 50-800 mg/kg i.p.) also produced dose-related, significant reductions (p < 0.05-0.001) of the fresh egg albumin-induced acute inflammation of the rat hind paw oedema. Furthermore, the plant extract (HPE, 50-800 mg/kg i.p.) produced dose-dependent, significant reductions (p < 0.05-0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. The results of this experimental animal study indicate that H. procumbens root aqueous extract possesses analgesic, antiinflammatory and hypoglycaemic properties, and lend pharmacological support to the suggested folklore uses of Harpagophytum procumbens root in the management and/or control of painful, arthritic and other inflammatory conditions, as well as for adult-onset, type-2 diabetes mellitus in some communities of South Africa.     

Anti-inflammatory and analgesic properties of the leaf extracts and essential oil of Lavandula angustifolia Mill

Extracts obtained from the leaves of Lavandula angustifolia Mill. (Lamiaceae) are used in Iranian folk medicine as remedies for the treatment of various inflammatory diseases. For evaluation of its probable analgesic and anti-inflammatory effects, hydroalcoholic extract, polyphenolic fraction and essential oil of the leaves of the herb were prepared and their analgesic effects were studied in mice using formalin and acetic acid-induced writhing tests. Carrageenan test in rats was used for assessment of anti-inflammatory activity of above-mentioned fractions. Results showed that while the hydroalcoholic extract (400-1600 mg/kg, p.o.) inhibited only the second phase of formalin test, the polyphenolic fraction (800 and 1600 mg/kg, p.o.) and essential oil (100 and 200 mg/kg, p.o.) suppressed both phases. In acetic acid-induced writhing test, polyphenolic fraction (400 and 800 mg/kg, p.o.) and essential oil (100 and 200 mg/kg, p.o.) reduced the number of abdominal constrictions. Essential oil at a dose of 200mg/kg also inhibited carrageenan-induced paw edema. Results of the present study confirm the traditional use of Lavandula angustifolia for the treatment of painful and inflammatory conditions and calls for further investigations to determine the active chemical constituent(s).     

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.     

辣椒免加热法提取物的镇痛作用研究

目的考察采用免加热提取工艺得到的辣椒提取物的镇痛作用强弱。方法采用小鼠热板法疼痛模型,比较免加热工艺辣椒酯提取物(EE)和水提取物(AE)灌胃给药后对小鼠痛阈的影响。结果灌胃给予小鼠EE(960,1 920 mg/kg)和AE(960,1 920,3 840 mg/kg)明显延长热板致痛小鼠的痛阈。两种提取物中960 mg/kg剂量组出现镇痛作用的时间有差异。结论免加热辣椒水提取物和酯提取物均有镇痛作用,但相同剂量下酯提取物显效较快。