Antinociceptive and antidepressant like effects of Securidaca longepedunculata root extract in mice

The aqueous root extract of Securidaca longepedunculata (polygalaceae) was investigated for possible antinociceptive and central nervous system (CNS) effects in mice. Three nociceptive models; acetic acid, formalin and tail-flick tests were used to study the antinociceptive activity. Rectal temperature test was employed as an adjunct to the nociceptive models. The extract at 200 and 400 mg/kg significantly and dose dependently reduced the nociception induced by the acetic acid and in the early phase of formalin test (P<0.05). The extract exerted significant (P<0.05) hypothermic effect in the 15 and 30 min of the rectal temperature test. The antinociceptive and hypothermic effects were partially reversed by naloxone (1mg/kg). The tail-flick test produced an insignificant increase in tail-flick latency at 400 mg/kg after 60 min of the test, but significantly (P<0.05) increase tail-flick latency in the 400mg/kg group of animals pre-treated with naloxone (1 mg/kg) after 120 min of the test. The extract also produced a significant (P<0.05) naloxone reversible antidepressant like effect in the forced swimming test (an animal model of depression). Collectively, these results suggest that the extract possess antinociceptive and antidepressant like effects with possible involvement of opioidergic pathways. The extract at limit dose of 2 g/kg body weight appeared to be safe in oral formulation.     

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.     

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.     

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.).     

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.     

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.     

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.     

Hypericum triquetrifolium Turra. extract exhibits antinociceptive activity in the mouse

The aim of the present study was to investigate the antinociceptive activity of Hypericum triquetrifolium Turra. extract. The lyophilized extract was administered to male Swiss mice. Formalin paw test and tail flick tests were used for the evaluation of the antinociceptive activity. Plant extract (10, 25, 50 and 60 mg kg(-1), i.p.) (n = 16-24 for each group) or vehicle (n = 27) was administered 30 min before the subplantar formalin injection. In the tail flick test, mice were examined for latency to withdraw their tails from a noxious thermal stimulus using a tail flick meter (n = 8 for each group). The effects of the extract on sensorimotor performance was also assessed (n = 16-24 for each group). The extract caused a significant dose-related inhibition of the first phase (50, 60 mg kg(-1), i.p.) and second phase (10, 25, 50 and 60 mg kg(-1), i.p.) of formalin induced hindpaw licking. Additionally, the extract administration (50, 60 mg kg(-1), i.p.) increased the tail flick latencies. No significant change was observed in any of the treatment groups in the sensorimotor performance test. The observed antinociceptive activity of the extract may be due to its noradrenaline and serotonin reuptake blocking activity. Moreover, the probable antiinflammatory activity of the extract may play a role in the dose-related inhibition of the second phase of formalin paw test.     

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.