Tail Immersion Test Research Articles

Analgesic, anti-inflammatory and anti-pyretic activities of D-3-O-methylchiroinositol isolated from stem bark of Piliostigma thonningii

D-3-O-methylchiroinositol isolated from the stem bark of Piliostigma thonningii was evaluated for analgesic, anti-inflammatory and anti-pyretic activities. The compound was screened for analgesic activity by the acetic acid-induced writhing and tail immersion tests. The anti-inflammatory activities were evaluated by the carrageenan-induced paw edema and Freund adjuvant-induced arthritis tests, while its anti-pyretic activity was determined using the yeast-induced pyrexia test. D-3-O-methylchiroinositol (10, 30 and 60 mg/kg) significantly (P < 0.01) reduced the number of acetic acid-induced writhing. In the tail immersion test, by 15, 45, 30 and 60 min post-treatment, tail withdrawal times in D-3-O-methylchiroinositol (30 and 60 mg/kg) were significantly (P < 0.01) longer compared to reaction times recorded in control group. The paw volumes obtained in the 60 mg/kg D-3-O-methylchiroinositol group by 1 h post-carrageenan injection were significantly (P < 0.05) lower than the paw volume of control rats. At 2 and 3 h, the paw volumes in the D-3-O-methylchiroinositol (10, 30 and 60 mg/kg) were significantly (P < 0.05) lower than paw volume of the control group. In the subacute phase of arthritis (18 h), paw volumes in D-3-O-methylchiroinositol (30 and 60 mg/kg) were significantly (P < 0.05 and P < 0.01, respectively) lower compared to paw volume in the control group. In the chronic phase (30 days) of arthritis, paw volumes in the D-3-O-methylchiroinositol (10, 30 and 60 mg/kg) were significantly (P < 0.01) lower than paw volume of the control group. The rectal temperatures of the 60 mg/kg D-3-O-methylchiroinositol were significantly lower at 1, 2, 3, 4 and 5 h post-yeast injection compared to those of the control. The findings of this study establish that D-3-O-methylchiroinositol has analgesic, anti-inflammatory and anti-pyretic activities.

Analgesic and Anti-Inflammatory Properties of Gelsolin in Acetic Acid Induced Writhing, Tail Immersion and Carrageenan Induced Paw Edema in Mice.

Plasma gelsolin levels significantly decline in several disease conditions, since gelsolin gets scavenged when it depolymerizes and caps filamentous actin released in the circulation following tissue injury. It is well established that our body require/implement inflammatory and analgesic responses to protect against cell damage and injury to the tissue. This study was envisaged to examine analgesic and anti-inflammatory activity of exogenous gelsolin (8 mg/mouse) in mice models of pain and acute inflammation. Administration of gelsolin in acetic acid-induced writhing and tail immersion tests not only demonstrated a significant reduction in the number of acetic acid-induced writhing effects, but also exhibited an analgesic activity in tail immersion test in mice as compared to placebo treated mice. Additionally, anti-inflammatory function of gelsolin (8 mg/mouse) compared with anti-inflammatory drug diclofenac sodium (10 mg/kg)] was confirmed in the carrageenan injection induced paw edema where latter was measured by vernier caliper and fluorescent tomography imaging. Interestingly, results showed that plasma gelsolin was capable of reducing severity of inflammation in mice comparable to diclofenac sodium. Analysis of cytokines and histo-pathological examinations of tissue revealed administration of gelsolin and diclofenac sodium significantly reduced production of pro-inflammatory cytokines, TNF-α and IL-6. Additionally, carrageenan groups pretreated with diclofenac sodium or gelsolin showed a marked decrease in edema and infiltration of inflammatory cells in paw tissue. Our study provides evidence that administration of gelsolin can effectively reduce the pain and inflammation in mice model.

Evaluation of antinociceptive activity of ethanol extract of bark of Polyalthia longifolia

Ethnopharmacological relevancePolyalthia longifolia var. pendula is a very popular herb in Bangladesh due to its traditional uses in treatment of rheumatism, bone fracture and gastric ulcer. The present study was conducted to investigate the antinociceptive activity of ethanol extract of P. longifolia (EEPL) bark. Materials and methodsHot plate and tail immersion tests, acetic acid-induced writhing test, glutamate and formalin-induced paw licking tests in mice were employed in this study. In all the experiments EEPL was administered orally at the doses of 50, 100 and 200mg/kg body weight. To investigate the possible participation of opioid system in EEPL-mediated effects, naloxone was used to antagonize the action. ResultsEEPL showed a significant antinociceptive activity against both heat and chemical-induced nociception. The effects were dose-dependent and significant at the doses of 100 and 200mg/kg of EEPL. Besides, pretreatment with naloxone caused significant inhibition of the antinociceptive activity induced by EEPL, revealing the possible involvement of the opioid receptors. ConclusionThese results indicate the antinociceptive activity of the bark of P. longifolia and support the ethnomedical use of this plant in treatment of different painful conditions.

Anti-nociceptive activity of the crude extract of Myrianthus arboreus P. Beauv (Cecropiaceae) in mice

Ethnopharmacological relevanceMyrianthus arboreus P. Beauv (Cecropiaceae) is a shrub or a tree plant widely distributed in Tropical Africa. In the South Eastern part of Nigeria, the leaves are used in traditional medicine as an analgesic for muscular pains, and also as an enema to relieve pain in the back and loins. Although no scientific study has been performed to validate its traditional use in pain management, this study therefore aims at investigating the anti-nociceptive activity of M. arboreus leaves extract in mice. Materials and methodsAnti-nociceptive activity of M. arboreus was investigated using acetic acid induced writhing, formalin induced paw licks, hot plate, and tail flick tests. Acute toxicity was determined using a slightly modified Lorkes method. ResultsThe extract of M. arboreus produced a significant dose-dependent [F (4, 20)=13.48 p<0.001] inhibition of abdominal writhings induced by acetic acid. In the formalin paw licking test, it produced a significant dose-dependent inhibition of neurogenic and inflammatory pain [F (4, 17.5)=60.13 p<0.001]. It also produced a significant dose dependent [F (4, 20)=30.5 p<0.001; F (4, 20)=0.321 p<0.0001] prolongation of the latency and reaction time in the hot plate and tail immersion tests. Peak effect was observed at the highest dose (40mg/kg). LD50 of the plant was found to be 894mg/kg. ConclusionM. arboreus possesses potent antinociceptive activity mediated centrally and peripherally, an effect which may justify its traditional use in the management of pain.

Qualitative phytochemical screening and evaluation of anti-inflammatory, analgesic and antipyretic activities of Microcos paniculata barks and fruits

ObjectiveThe main objectives of this study were to qualitatively evaluate the profile of phytochemical constituents present in methanolic extract of Microcos paniculata bark (BME) and fruit (FME), as well as to evaluate their anti-inflammatory, analgesic and antipyretic activities. MethodsPhytochemical constituents of BME and FME were determined by different qualitative tests such as Molisch's test, Fehling's test, alkaloid test, frothing test, FeCl3 test, alkali test, Salkowski's test and Baljet test. The anti-inflammatory, analgesic and antipyretic activities of the extracts were evaluated through proteinase-inhibitory assay, xylene-induced ear edema test, cotton pellet-induced granuloma formation in mice, formalin test, acetic acid-induced writhing test, tail immersion test and Brewer's yeast-induced pyrexia in mice. ResultsM. paniculata extracts revealed the presence of carbohydrates, alkaloids, saponins, tannins, flavonoids and triterpenoids. All of the extracts showed significant (P<0.05, vs aspirin group) proteinase-inhibitory activity, whereas the highest effect elicited by plant extracts was exhibited by the BME (75.94% proteinase inhibition activity) with a half-maximal inhibitory concentration (IC50) of 61.31 μg/mL. Each extract at the doses of 200 and 400 mg/kg body weight showed significant (P<0.05, vs control) percentage inhibition of ear edema and granuloma formation. These extracts significantly (P<0.05, vs control) reduced the paw licking and abdominal writhing of mice. In addition, BME 400 mg/kg, and FME at 200 and 400 mg/kg showed significant (P<0.05, vs control) analgesic activities at 60 min in the tail immersion test. Again, the significant (P<0.05, vs control) post-treatment antipyretic activities were found by BME 200 and 400 mg/kg and FME 400 mg/kg respectively. ConclusionStudy results indicate that M. paniculata may provide a source of plant compounds with anti-inflammatory, analgesic and antipyretic activities.

Antinociceptive and antiulcer activities of Pycnanthus angolensis

Pycnanthus angolensis (Welw) Warb., Myristicaceae, is used in Nigeria folk medicine to treat complaints such as toothache, headache, sore throat, ulcers and wounds. The aim of the study was to investigate the antinociceptive and antiulcer activities of the stem bark extract of Pycnanthus angolensis. Acute toxicity was conducted with a single oral dose of 5g/kg. Antinociceptive activity was evaluated in acetic acid-induced writhing, formalin and tail immersion tests in mice while antiulcer activity was evaluated in ethanol and indomethacin-induced models in rats. In acetic acid-induced writhing test, the extract (50, 100 and 150mg/kg, p.o.), significantly reduced the number of writhes (46.75%, 57.28% and 75.69%) respectively, compared to control. The extract significantly (p<0.001) reduced the time spent in licking the hind paw at both phases, in formalin test. In tail immersion test, significant antinociceptive effect was only observed with the dose of 150mg/kg, with peak effect at 90min (43.38%). There is no significant change in the spontaneous locomotor activity of animals in the open field. The extract prevented the gastric ulceration caused by ethanol and indomethacin treatments compared to control. The results showed that P. angolensis extract possesses antinociceptive and antiulcer activities supporting the traditional use for relieving pain and ulcers.

Antinociceptive and Anti-Inflammatory Activities of the Aqueous Leaf Extract of Tamarindus indica L. in Albino Rats

The research was conducted to investigate the phytochemical constituents, acute toxicity, the anti-inflammatory and antinociceptive activities of the aqueous extract of Tamarindus indica L. (AQETI) leaves. Phytochemical constituents present in AQETI were found to be flavonoids, cardiac glycosides, tannins and terpenoids which might be responsible for the established anti-inflammatory and antinociceptive activities in the plant extract. The leaf extract of the plant was found to be moderately toxic with an intraperitoneal acute toxicity (i.p. LD50) of 566 mg/kg. AQETI produced significant (p < 0.05) and dose-dependent anti-inflammatory and antinociceptive activities. AQETI (400 mg/kg) exhibited a maximum percentage inhibition (56.97%) in acetic acid-induced writhing response and at 30 min increased the pain threshold by 100 % in the tail immersion test. In the hot plate method, AQETI (400 mg/kg) showed a similar percentage inhibition (84.62%) at 30 and 60 min. The results demonstrate that the aqueous extract of Tamarindus indica L. leaves contains some pharmacologically active substances, was moderately toxic and possessed significant anti-inflammatory and antinociceptive acivities.

Synthesis and antinociception properties of phencyclidine derivatives with modified aromatic or cycloalkyl rings and amino group

Phencyclidine is an arylcyclohexylamine compound which has received a lot of investigative attention due to the complex spectrum of behaviours and its complicated interactions with the central nervous system. Phencyclidine administration may act as stimulant, depressant, hallucinogen, and analgesic depending on dose and tested species. In this study, new phenyl and thienyl analogues with specific affinity for the phencyclidine sites in NMDA receptors, dopamine uptake blocking, or both of them were synthesized. The acute and chronic pain properties of these compounds were studied using the tail immersion and formalin tests on mice and the results were compared with control and phencyclidine groups at a dose of 10 mg/kg. The outcomes indicated that all synthesized compounds showed better activities to decrease acute thermal and chemical, but not chronic pains. Also, these effects were more significant for phenyl (group 1) compared to thiophene (group 2) analogues, which is probably due to the higher affinity of group 1 for inhibition of dopamine reuptake compared to binding to the phencyclidine sites in NMDA receptors in this family.

Antinociceptive effects, acute toxicity and chemical composition of Vitex agnus-castus essential oil.

Vitex agnus-castus (VAC) and its essential oil have been traditionally used to treat many conditions and symptoms such as premenstrual problems, mastalgia, inflammation, sexual dysfunction, and pain. In this study, the effects of essential oil extracted from Vitex agnus-castus (EOVAC) leaves were investigated in three behavioral models of nociception in adult male Wistar rats. Chemical composition of EOVAC was analyzed using gas chromatography - mass spectrometry (GC-MS) and also its possible toxicity was determined in mice. Analgesic effect of EOVAC was determined using tail immersion test, formalin test, and acetic acid-induced visceral pain in rats. EOVAC (s.c.) and morphine (i.p.) significantly (p<0.05) reduced pain responses in both formalin and tail immersion tests.In the study of evolved mechanisms,pretreatment with naloxone or atropine significantly (p <0.05) reversed the essential oil-induced analgesia in both formalin and tail immersion tests. Moreover, EOVAC and Piroxicam produced significant (p<0.05) inhibition in the acetic acid-induced writhing response. EOVAC did not show any mortality even at high dose (5 g/kg, p.o.) of administration in toxicity test. Moreover, according to GC-MS results, major components of the EOVAC were α-pinene (14.83%), limonene (10.29%), β-caryophyllene (6.9%), sabinene (5.27%), and β-farnesene (5.9%). These results suggest that endogenous opioidergic system as well as muscarinergic receptors of cholinergic system may be involve in the antinociceptive activity of Vitex agnus-castus essential oil in these models of pain in rats.

Antinociceptive action of diphenyl diselenide in the nociception induced by neonatal administration of monosodium glutamate in rats

Monosodium glutamate (MSG) is a neuroexcitatory amino acid commonly used as flavoring of foods. MSG neonatal administration to animals leads to behavioral and physiological disorders in adulthood, including increased pain sensitivity. This study aimed to investigate the effect of diphenyl diselenide (PhSe)2, an organoselenium compound with pharmacological properties already documented, on nociception induced by MSG. Newborn Wistar rats received 10 subcutaneous injections of MSG at a dose of 4.0g/kg or saline (once daily). At the 60th day of life, the rats were daily treated with (PhSe)2 (1mg/kg) or vehicle (canola oil) by the intragastric route for 7 days. The behavioral tests (locomotor activity, hot plate, tail-immersion and mechanical allodynia) were carried out. Ex vivo assays were performed in samples of hippocampus to determine Na+, K+-ATPase and Ca2+-ATPase activities, cytokine levels and [3H]glutamate uptake. The results demonstrated that MSG increased nociception in the hot plate test and in the mechanical allodynia stimulated by Von-Frey hair but did not alter the tail immersion test. (PhSe)2 reversed all nociceptive behaviors altered by MSG. MSG caused an increase in Na+,K+-ATPase and Ca2+-ATPase activities and in pro-inflammatory cytokine levels and a decrease in the anti-inflammatory cytokine and in the [3H]glutamate uptake. (PhSe)2 was effective in reversing all alterations caused by MSG. The results indicate that (PhSe)2 had a potential antinociceptive and anti-inflammatory action in the MSG model.

Contributions of spinal d-amino acid oxidase to chronic morphine-induced hyperalgesia

Spinal d-amino acid oxidase (DAAO) is an FAD-dependent peroxisomal flavoenzyme which mediates the conversion of neutral and polar d-amino acids (including d-serine) to the corresponding α-keto acids, and simultaneously produces hydrogen peroxide and ammonia. This study has aimed to explore the potential contributions of spinal DAAO and its mediated hydrogen peroxide/d-serine metabolism to the development of morphine-induced hyperalgesia. Bi-daily subcutaneous injections of morphine to mice over 7 days induced thermal hyperalgesia as measured by both the hot-plate and tail-immersion tests, and spinal astroglial activation with increased spinal gene expression of DAAO, glial fibrillary acidic protein (GFAP) and pro-inflammatory cytokines (interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α)). Subcutaneous injections of the potent DAAO inhibitor CBIO (5-chloro-benzo[d]isoxazol-3-ol) prevented and reversed the chronic morphine-induced hyperalgesia. CBIO also inhibited both astrocyte activation and the expression of pro-inflammatory cytokines. Intrathecal injection of the hydrogen peroxide scavenger PBN (phenyl-N-tert-butylnitrone) and of catalase completely reversed established morphine hyperalgesia, whereas subcutaneous injections of exogenous d-serine failed to alter chronic morphine-induced hyperalgesia. These results provided evidence that spinal DAAO and its subsequent production of hydrogen peroxide rather than the d-serine metabolism contributed to the development of morphine-induced hyperalgesia.

Antinociceptive effect of methanol extract of leaves of Persicaria hydropiper in mice.

BackgroundPersicaria hydropiper (Linn.) Delarbre is a common plant of Polygonaceae family commonly called Bishkatali in Bangladesh. Leaves of the plant are traditionally used in the treatment of rheumatic pain, gout, and skin diseases such as ringworms, scabies, boils, abscesses, carbuncles, bites of snakes, dogs or insects. This study evaluated the antinociceptive effect of the methanol extract of P. hydropiper leaves (MEPH).MethodsThe antinociceptive activity of MEPH was investigated using heat-induced (hot-plate and tail-immersion test) and chemical-induced (acetic acid, formalin, glutamic acid, cinnamaldehyde) nociception models in mice at 25, 50, and 75 mg/kg doses. Involvement of opioid system, cyclic guanosine monophosphate (cGMP) pathway, and ATP-sensitive K+ channel pathway were also tested using naloxone, methylene blue and glibenclamide respectively.ResultsMEPH showed antinociceptive activity in both heat- and chemical induced pain models. In both hot plate and tail immersion tests MEPH significantly increases the latency to the thermal stimuli. In acetic acid-induced writhing test the extract inhibited the number of abdominal writhing. Likewise, MEPH produced significant dose-dependent inhibition of paw licking in both neurogenic and inflammatory pain induced by intraplantar injection of formalin. Besides, MEPH also significantly inhibited the glutamate-induced pain and cinnamaldehyde-induced pain in mice. It was also clear that pretreatment with naloxone significantly reversed the antinociception produced by MEPH in hot plate and tail immersion test suggesting the involvement of opioid system in its effect. In addition, administration of methylene blue, a non specific inhibitor of NO/guanylyl cyclase, enhanced MEPH induced antinociception while glibenclamide, an ATP-sensitive K+ channel antagonist, could not reverse antinociceptive activity induced by MEPH.ConclusionBased on the results of the current study it can be said that MEPH possesses significant antinociceptive activity which acts in both peripheral and central mechanisms.

Toxic essential oils. Part IV: The essential oil of Achillea falcata L. as a source of biologically/pharmacologically active trans-sabinyl esters

Herein we report on the comprehensive chemical analysis of the essential oils obtained from above- and underground parts of a previously unreported chemotype of Achillea falcata L. (Asteraceae) and, for the first time, on the biological/toxicological profile of its dominant/newly discovered volatile metabolites. Detailed spectral analyses, in combination with chemical synthesis and theoretical study, of selected constituents, enabled the identification of trans-sabinol and its esters – the formate, tiglate (new compounds), acetate, butanoate, isobutanoate, 2-methylbutanoate and 3-methylbutanoate – in both aerial and underground parts of A. falcata. Evaluation of acute toxicity in Artemia salina model, in vitro and in silico (molecular docking) evaluation of acetylcholinesterase inhibitory activity and in vivo (mice) evaluation of antinociceptive activity (hot plate, tail immersion and acetylcholine-induced abdominal writhing tests) of trans-sabinol and its esters suggested that they may interact with different targets in crustacean/mammalian organisms. Alongside moderate acute toxicity (LD50 (48 h) = 0.03–0.26 mmol/L), the tested compounds exert influence on both the peripheral and central nervous systems (in the hot plate test, trans-sabinyl tiglate, at 50 mg/kg, produced a 140% baseline increase 15 min after the treatment) and to moderately inhibit acetylcholinesterase (at the concentration of 20 µg/mL, these compounds caused a reduction of acetylcholinesterase activity up to 40%).

Ameliorative potential of Ocimum sanctum in chronic constriction injury-induced neuropathic pain in rats.

The present study was designed to investigate the ameliorative potential of Ocimum sanctum and its saponin rich fraction in chronic constriction injury-induced neuropathic pain in rats. The chronic constriction injury was induced by placing four loose ligatures around the sciatic nerve, proximal to its trifurcation. The mechanical hyperalgesia, cold allodynia, paw heat hyperalgesia and cold tail hyperalgesia were assessed by performing the pinprick, acetone, hot plate and cold tail immersion tests, respectively. Biochemically, the tissue thio-barbituric acid reactive species, super-oxide anion content (markers of oxidative stress) and total calcium levels were measured. Chronic constriction injury was associated with the development of mechanical hyperalgesia, cold allodynia, heat and cold hyperalgesia along with an increase in oxidative stress and calcium levels. However, administration of Ocimum sanctum (100 and 200 mg/kg p.o.) and its saponin rich fraction (100 and 200 mg/kg p.o.) for 14 days significantly attenuated chronic constriction injury-induced neuropathic pain as well as decrease the oxidative stress and calcium levels. It may be concluded that saponin rich fraction of Ocimum sanctum has ameliorative potential in attenuating painful neuropathic state, which may be attributed to a decrease in oxidative stress and calcium levels.

Exploration of Analgesic Activity of the Ethanolic Extract of Erythrina variegate Bark.

The aim of this study was to evaluate analgesic activity of the ethanolic extract of the bark of Erythrina variegata . The analgesic potential of the extract was evaluated using acetic acid-induced writhing test for peripheral analgesic activity and tail immersion, hot plate, formalin and glutamate test at 50, 100, and 200 mg/kg body weight doses. In analgesic activity tests, the extract at the doses of 50, 100, and 200 mg/kg b.w. produced a remarkable increase in pain threshold in a dose dependent manner. In acetic acid induced writhing test, the inhibitory effect was to be parallel to the reference drug diclofenac sodium. The extract showed 18.89% writhing inhibitory effect at the dose 200 mg/kg b.w., whereas diclofenac sodium showed 79.42% inhibition of writhing at a dose of 10 mg/kg b.w. The results of tail immersion and hot plate test also showed potential analgesic activity of the extract which is also comparable to the standard drug morphine (5 mg/kg b.w.). In formalin test, the bark extract at doses 200 mg/kg b.w. were found to exhibit the highest 47.80% inhibitory effect in late phase, whereas the reference drug morphine showed 63.64% inhibitory effect on licking of the hind paw. In glutamate test, the bark extract at doses 200 mg/kg b.w. were found to exhibit the highest 68.07% inhibitory effect in late phase, whereas the reference drug diclofenac sodium showed 61.53% inhibitory effect on licking of the hind paw. In conclusion, it can be said that the plant part have potential analgesic activity and may be used to relief pain.

Study of Antinociceptive Activity of Kaempferia galanga from Bangladesh in Swiss albino Mice

Kaempferia galanga (K. galanga) (Family: Zingiberaceae) has been used in the folk medicine for the treatment of inflammation, chest pain, cholera, headache, toothache, hypertension, and abdominal pain. Previous investigations on this plant suggested that the methanol extract of rhizome showed the analgesic activity. Therefore, the present study investigated the antinociceptive activity of different extracts of rhizome and leaves of K. galanga. The antinociceptive activity was evaluated by using acetic acid-induced writhing, hot plate and tail immersion tests in Swiss albino mice at the doses of 100 and 200 mg/kg body weight p.o. The acetone extract of rhizome (ACR), as well as petroether fraction (PEF), chloroform fraction (CHF), methanol fraction (MEF) and acetone extract of leaves (ACL) were examined for antinociceptive activity. In this study, all the extracts displayed significant (p<0.05 and p<0.001) antinociceptive action in a dose dependent manner. In acetic acid induced writhing method, chloroform and methanol extract of rhizome (200 mg/kg) showed 81.22% and 70.12% writhing inhibition, respectively whereas the standard drug Diclofenac-sodium (25 mg/kg) and Aspirin (100 mg/kg) exhibited 80.72% and 61.94% inhibition. In hot plate and tail immersion tests, the petroether extract of rhizome and acetone extract of leaves (200 mg/kg) produced maximum 69.41% and 81.69% nociception inhibition of thermal stimulus respectively. In this study Morphine (5 mg/kg) was used as standard. The present study revealed that the acetone extracts and fractions of rhizome and leaves of K. galanga possess an antinociceptive property which supports its use in traditional medicine and suggesting that the plant may be further investigated to discover its pharmacologically active natural products.

Evaluation of Analgesic and CNS Depressant Activities of Grewia Paniculata in Swiss albino Mice

Grewia paniculata (Family: Malvaceae) used to treat inflammation, pain, fever, wounds and also in psychological disorders. The present study was designed to investigate the analgesic and CNS depressant activities of different crude extract of Grewia paniculata. The analgesic activity was evaluated by using acetic-acid induced writhing, hot plate and tail immersion tests and the CNS depressant activity was examined by observing the reduction of locomotor and exploratory activities in the thiopental induced sleeping time, hole cross and open field tests in mice at the doses of 250 and 500 mg/kg, b.w. For analgesic and CNS depressant activity Diclofenac sodium (25 mg/kg i.p), Aspirin (100 mg/kg p.o), Morphine (5 mg/kg i.p) and Diazepam (1 mg/kg i.p) were used as reference drug, respectively. All the extract displayed significant analgesic effect (P<0.05-0.001) in acetic acid and heat induced pain models in a dose dependent manner. The extract prolonged the latency period to the thermal stimuli in both hot plate and tail immersion test. The spontaneous motor activity was decreased by (P<0.001) by all natural products in both hole cross and open field test. Statistical studies revealed that all the extracts prolong the duration of the thiopental sodium induced sleeping time in mice. Altogether, these results suggest that all the extracts of Grewia paniculata possesses potent analgesic and CNS depressant properties, which support its use in traditional medicine and suggesting that the plant should be further investigated for its pharmacological active natural products.

Phytochemical, analgesic, antibacterial, and cytotoxic effects of Alpinia nigra (Gaertn.) Burtt leaf extract

This research evaluated the phytochemical contents as well as the analgesic, cytotoxic, and antimicrobial effects of the methanolic extract of Alpinia nigra leaf. Phytochemical analysis was carried out using established methods. The analgesic effects of the extract were measured with the formalin test and tail immersion test. The antibacterial activity of the extract was evaluated using the disc diffusion technique. Cytotoxicity was assessed with the brine shrimp lethality bioassay. Data were analyzed with one-way analysis of variance using statistical software (SPSS, Version 19.0). The qualitative phytochemical screening of A. nigra leaf extract showed the presence of medicinally active secondary metabolites such as alkaloids, glycosides, cardiac glycosides, flavonoids, steroids, tannins, anthraquinone glycosides, and saponins. The extract at a dose of 200 mg/kg revealed a prevailed central nociception increasing the reaction time in response to thermal stimulation. The extract also showed a response to chemical nociceptors, causing pain inhibition in the late phase. The leaf extract (2 mg/disc) showed mild antibacterial activity compared to tetracycline (50 μg/disc). In the brine shrimp lethality bioassay, the LC50 (lethal concentration 50) value of the extract was found to be 57.12 μg/mL, implying a promising cytotoxic effect. The results evidenced the moderate analgesic and antibacterial effects with pronounced cytotoxic capability.

English

The knowledge of pharmacological activity is mainly derived from the use that the population makes of plants. Rue (Ruta graveolens L.) is popularly used with a degree of mysticism due to its anti-inflammatory, healing, sedative and antispasmodic characteristics. In an attempt to confirm the well-known analgesic effects, the present study evaluated Rue extracts in animal models. Two organic extracts were produced and orally administered to mice, approximately 30 min before the tail immersion test in warm water (55 ± 0.5°C). The results reveal a small chronic analgesic effect and a high effect in acute essay (62.1% of pain inhibition) especially observed in the hexane extract, supporting the hypothesis of the use of this plant as having analgesic activity. However, the reports of the population about its analgesic activity should be caused also by its anti-inflammatory characteristics and the presence of compounds related in literature as analgesics. Further experiments should be done to better determine the dose-response analgesic effect of R. graveolens extracts. Key words: Ruta graveolens, analgesic effect, tail immersion, rue.

Effect of Gabapentin and Pregabalin in Rat Model of Taxol Induced Neuropathic Pain.

Chemotherapy induced neuropathy pain remains as a major dose limiting side effect of many commonly used chemotherapeutic drugs. Presently newer antiepileptic agents have been developed with improved safety and tolerability profiles in alleviating neuropathic pain. To evaluate the effect of Gabapentin and Pregabalin in Paclitaxel (Taxol) induced neuropathic pain and to compare the effect of these drugs in animal models. Rats were randomly divided into four groups of six animals each. Group 1- vehicle, Group 2 - Paclitaxel (2mg/kg), Group 3 - Gabapentin (60mg/kg) with Paclitaxel, Group 4 - Pregabalin (30mg/kg) with Paclitaxel. Pain was induced by intraperitoneal injection of Paclitaxel on four alternate days. After taking the baseline values, the drugs treated groups (group 3 and 4) were administered with respective drugs once a day orally for eight consecutive days along with paclitaxel. All the animals were tested for thermal hyperalgesia and cold allodynia on day 0, 7, 14, 21 and 28 with Radiant heat method and Tail immersion test, Acetone drop method respectively. In Radiant heat method, gabapentin and pregabalin treated animals found to have significant increase in the tail latency period compared to control and paclitaxel treated groups in all periods of observation. Acetone drop test and tail immersion test also showed significant response similar to Radiant heat method. Pregabalin showed highly significant effect when compared to gabapentin group. Both gabapentin and pregabalin produced significant anti-hyperalgesic and anti-allodynic effects in experimental animal models. Pregabalin treated group showed highly significant effect compared to gabapentin treated animals.