In vivo hepatoprotective and in vitro antimicrobial potential of Ceasalpinia bonduc (Linn): Pharmacological correlation with identified phytochemicals.

The in vivo hepatoprotective potential of methanolic extract of Ceasalpinia bonduc (CBLM) has been explored against carbon tetrachloride (CCl4) induced acute liver injury in rats. Treatment of plant extract on CCl4 intoxicated liver significantly reduced the hepatoxicity, along with serum enzymes GPT and GOT. To explore the chemical constituents from CBLM extract, it was fractionated into non-polar to moderately polar fractions (CBLM-H, CBLM-HEt, CBLM-Et, CBLM-EtM, CBLM-M) and subjected to GC/GC-MS analysis. Altogether twenty seven (~71%) phytochemicals were identified from different fractions by using Electronic Mass Spectral Library GC-MS (NIST 20). Out of which twenty one are first time reported from Ceasalpinia bonduc, fourteen from genus Caesalpinia and ten from family Fabaceae. The identified phytochemicals 2-ethyl-2-hydroxy-1,3-dimethylcyclopentanecarboxylic acid, ethyl ester (21) and 1,3,5-triazine-2,4-diamine,6-hydroxy-N,N-dicyclohexyl (23) are first time identified as plant metabolites. To explore the antimicrobial potential four strains of Gram-positive and eight strains of Gram-negative bacteria were used along with pure cultures of five saprophytic fungus (molds) and two strains of yeast were utilized. CBLM-H and CBLM-HEt were exhibited praiseworthy antimicrobial potential. CBLM-H showed complete growth inhibition of P. mirabilis and V. cholerae at the concentration of 0.1g/mL while CBLM-HEt at 0.05g/mL halted the growth of S. aureus.

Neurochemical and behavioral effects of Nigella sativa and Olea europaea oil in rats.

OBJECTIVES: In the last few decades, therapeutic uses of medicinal compounds present in food as a normal constituent has risen substantially, largely because of their fewer side effects and adequate efficacy. This study is designed to investigate a role of brain serotonin (5-HT) and dopamine (DA) in the potential nootropic, anxiolytic, and other beneficial effects of Nigella sativa (NS) and Olea europaea (OE) oil in rat models. METHODS: Animals were treated with NS and OE oil orally at doses of 0.1 ml/kg and 0.25 ml/kg for 5 weeks. Food intake and body weight change, anxiety-like effects in elevated plus maze and activity in a novel and familiar environment were monitored weekly. Effects on learning and memory after 5 weeks treatment were monitored using Morris water maze test. Neurochemical analysis was carried using HPLC-ECD method. RESULTS: NS and OE oil administration enhanced learning and memory in Morris water maze test and the effects were greater in NS than OE oil-treated animals. Low dose of OE oil increased exploration in an open field, higher dose of OE oil and both doses of NS oil produced no consistent effect on open field exploration. Effects of both oils on anxiety-like behavior, food and water intake, and activity in activity box were either not consistent or did not occur. The treatment increased homovanillic acid (HVA). 5-HT levels increased in high dose of NS oil and low dose of OE oil-treated groups. Low dose NS oil decreased 5-HT. DISCUSSION: The present study suggests that active components in NS and OE oil may prove useful in treating impaired cognition. OE oil may produce psychostimulant-like effect. Modulation of DA and serotonin neurotransmission seems important in the pharmacological effect of these oils.

Antidepressant-like deliverables from the sea: evidence on the efficacy of three different brown seaweeds via involvement of monoaminergic system.

Brown seaweeds exhibit several health benefits in treating and managing wide array of ailments. In this study, the antidepressant-like effect of methaolic extracts from Sargassum swartzii (SS), Stoechospermum marginatum (SM), and Nizamuddinia zanardinii (NZ) was examined in forced swimming test (FST), in rats. Oral administration of SS, SM, and NZ extract (30-60 mg/kg) exhibited antidepressant-like activity in FST by reducing immobility time as compared to control group, without inducing significant change in ambulatory behavior in open field test. In order to evaluate the involvement of monoaminergic system, rats were pretreated with the inhibitor of brain serotonin stores p-chlorophenylalanin (PCPA), dopamine (SCH23390 and sulpiride), and adrenoceptor (prazosin and propranolol) antagonists. Rats receiving treatment for 28 days were decapitated and brains were analyzed for monoamine levels. It may be concluded that the extracts of SS, SM, and NZ produces antidepressant-like activity via modulation of brain monoaminergic system in a rat model.

Sargassum swartzii extracts ameliorate memory functions by neurochemical modulation in a rat model.

Recently, considerable attention has been paid to drug exploration from natural sources for treating memory loss, a major manifestation of various neurodegenerative diseases. Increasing evidences implicate brain serotonin metabolism in learning and memory, supporting the notion that targeting 5-HT (5-hydroxytryptamine) and its receptors would be beneficial in the treatment of cognitive disorders. In the present study, behavioral and neurochemical effects were examined following administration of Sargassum swartzii extracts in albino Wistar rats. Increase in spatial working memory and recognition memory was exhibited by the seaweed-treated rats as compared to controls. Plasma tryptophan, brain 5-HT, and 5-hydroxyindoleacetic acid levels were measured using HPLC-ECD, and a significant increase in brain 5-HT metabolism was observed in the seaweed-treated rats. The increase in memory functions following repeated administration of S. swartzii extracts is suggested to be due to the increased serotonergic neurotransmission in the brain of seaweed-treated rats.

In-vitro assessment of cytotoxicity of halloysite nanotubes against HepG2, HCT116 and human peripheral blood lymphocytes.

Halloysite is a clay mineral with chemical similarity to kaolin, a pharmaceutical ingredient. It consists of mainly aluminosilicate nanotubular particles in the size range of ∼ 200-1000 nm. Many studies have tried to empirically explore this novel clay for its potential in drug delivery systems but no work has yet studied its cytotoxicity from the perspective of oral drug delivery system. In this study, the halloysite nanotubes (HNTs) were subjected to size distribution analyses, which reveal more than 50% of nanotubes in the size range of 500 nm and rest mainly in the sub micrometer range. HNTs were then evaluated for in-vitro cytotoxicity against HCT116 (colorectal carcinoma) and HepG2 (hepatocellular carcinoma) cells which represent the earliest entry point and the first accumulating organ, respectively, for nanoparticles en-route to systemic circulation after oral delivery. Moreover, HNTs were tested for their cytogenetic toxicity against human peripheral blood lymphocytes. Both these results collectively indicated that HNTs are generally safe at practical concentrations of excipients for oral dosage forms.

Artemisia annua as a possible contraceptive agent: a clue from mammalian rat model.

In a previous study, we evaluated the maternal and fetal safety of antimalarial herb Artemisia annua with artemisinin yield of 1.09%. Here, we attempted to ascertain the contraceptive claim of A. annua. Sexually matured female Wistar rats (180-220 g) were allotted into four study groups of six rats each. The control group received normal saline, while the A. annua-treated groups received 100, 200 and 300 mg/kg of A. annua for 2 weeks, followed by mating with proven fertile males (1:1). The rats were allowed to carry the pregnancy to term. At birth and weaning periods, selected reproductive outcome and fertility indices were determined. The results showed that A. annua significantly reduced litter size, reproductive outcome and fertility indices compared with the control (p <  0.05). These results imply that A. annua could serve as a prospective contraceptive agent in addition to its antimalarial activity.

Effect of dichloromethane fraction of Areca catechu nut on monoamines associated behaviors and tyramine pressor sensitivity in rodents.

The current study was aimed at investigating the effect of Areca catechu nut dichloromethane fraction (7 mg/kg) on monoamines (serotonin and dopamine) modulation (5-hydroxytryptophan-induced tremors and phenylethylamine-induced stereotypes) and its interaction with tyramine (cheese effect). The dichloromethane fraction caused pronounced increase in 5-HTP-induced tremors (50%) with negligible PEA-induced stereotypes (20%). Additionally, it did not produce a significant increase in the tyramine pressor effects. These results suggest that the dichloromethane fraction of A. catechu nut primarily elevates serotonin levels (probably via monoamine oxidase A inhibition) and does not induce cheese effect.

Biochemical and haematological evaluation of repeated dose exposure of male Wistar rats to an ethanolic extract of Artemisia annua.

Artemisia annua is widely used for the treatment of malaria and other disorders. In a previous study, the artemisinin concentration in the dry leaves of A. annua grown under humid tropical conditions was determined to be 1.098% using reversed phase high performance liquid chromatography. In the current study, biochemical and haematological evaluations of ethanolic leaf extracts derived from such plants (EAA) were carried out in 20 male Wistar rats. Rats were divided into four study groups of saline-treated (control) and test groups exposed orally to graded doses of EAA for 28 days. The results showed that the liver function and haematological indices, and testosterone levels were not adversely affected. High density lipoprotein -cholesterol was reduced at 100 mg/kg of EAA, atherogenic index as well as low density lipoprotein -cholesterol was raised, and glucose concentration was reduced significantly at the 100 and 200 mg/kg of EAA (p < 0.05). In addition to serving as a possible antidiabetic agent, EAA may not predispose users to hepatotoxicity, haematotoxicity and testicular toxicity. However, due to the possible risk of atherosclerosis, we advise that the plant extract should be taken with caution in people with atherosclerotic condition.

A safety assessment of the antimalarial herb Artemisia annua during pregnancy in Wistar rats.

Artemisia annua is a Chinese antimalarial herb that has been used for more than 2000 years. The maternal and foetal safety of the ethanolic leaf extract of therapeutically active Artemisia annua (EAA), with previously determined artemisinin yield of 1.098% was evaluated in Wistar rats. Twenty pregnant rats, divided into four study groups of saline treated (control), and test groups administered orally with 100, 200 and 300 mg/kg body weights of EAA, respectively, from gestation days (GD) 8 to 19. Following overnight fast, animals were sacrificed on GD 20, and maternal blood was collected to evaluate biochemical and haematological markers. Foetuses were carefully removed, weighed, and observed for any possible malformation. Biochemical and haematological studies revealed that EAA did not result in maternal hepatotoxicity, haematotoxicity, and hyperlipidemia. While litter size significantly decreased (p < 0.05) at 100 mg/kg EAA, maternal estrogen levels decreased in all the EAA-treated groups. Non-viable (21%) and malformed (31%) foetuses were observed at the 300 mg/kg dose of EAA, which implies that although consumption of the leaf extract may not predispose users to hepatotoxicity, haematotoxicity, and hyperlipidemia, it should be taken with caution during pregnancy due to possible risk of embryotoxicity at concentrations higher than the therapeutic dose.

Potential antidepressant activity of Areca catechu nut via elevation of serotonin and noradrenaline in the hippocampus of rats.

The current study was aimed at investigating the potential antidepressant activity of Areca catechu nut ethanol extract and its various fractions using behavioral (acute and sub-chronic forced swim tests) and biochemical (monoamines and their metabolite levels using high performance liquid chromatography) tests. The areca nut ethanol extract and its aqueous fraction exhibited antidepressant activity in both acute and sub-chronic forced swim tests (IC50 ~ 50 and 20 mg/kg, respectively), which was further confirmed by unaltered locomotor (horizontal and vertical) activities of rats in the activity cage. Phytochemical analysis revealed that saponins of areca nut may be the active component in its antidepressant action. The rats treated sub-chronically with areca nut extract displayed toxic effects, whereas its active aqueous fraction was non-toxic, indicating the presence of different constituents for antidepressant and toxic effects. In the hippocampus of rats, the areca nut extract (50 mg/kg) and aqueous fraction (20 mg/kg) caused a significant elevation of serotonin (around 35%) and noradrenaline (around 30%) compared with the control (261 ± 25 and 512 ± 29 ng/g, respectively). In conclusion, the areca nut possesses potential antidepressant effect via the elevation of serotonin and noradrenaline.

In-vitro immunomodulatory and anti-cancerous activities of biotransformed products of Dianabol through Azadirachta indica and its molecular docking studies.

BACKGROUND: Plant Biotransformation is one of the tools for structural modifications of the organic substrate of low, moderate or high biological value utilizing plant cultured cells, these modifications of organic structures may lead to biologically augmented products and which may be ultimately substantial in cure or improvement of various morbidities and diseases. RESULTS: Azadirachta indica A. Juss. suspension culture was employed for the biotransformation of dianabol (1) for the first time, and two metabolites, 17ß-hydroxy-17α-methyl-5α-androst-1-en-3-one (2), and 17ß-hydroxy-17α-methyl-5α-androstan-3-one (3) were obtained. CONCLUSIONS: Most important aspect of this work was the evaluation of metabolite 2, which strongly and differentially suppressed [not affecting whole blood and human polymorphonuclear cells (PMN)] the phytohemagglutinin (PHA)-activated T-cell proliferation (IC50: <10.33 µM), and also found to inhibit IL-2 production (IC50: 16.89 ± 1.32) unlike metabolite 3 and compound 1. Compound 2 also exhibited anticancer activity against lung cancer cell line; NCI-H460, it moderately inhibited the growth of cancer cells (22.5 ± 4.15 µM). Furthermore, a good correlation between the predicted binding energies of the compounds acquired by the FlexX program and the experimental affinities were speculated upon interacting with IL-2 protein during molecular docking studies.

Calcium antagonistic activity of Bacopa monniera in guinea-pig trachea.

OBJECTIVE: To demonstrate the calcium antagonistic property of ethanol extract of Bacopa monniera in guinea-pig trachea. MATERIALS AND METHODS: The dose response curves of CaCl(2) (1 × 10(-5) to 1 × 10(-1) M) were constructed in the absence and presence of ethanol extract of Bacopa monniera (100, 500 and 700 µg/ml) or nifedipine (1 × 10(-6) M) in guinea-pig trachea in calcium free high K(+)-MOPS-PSS (3-(N-morpholino)-propanesulphonic acid physiological salt solution). The data was analyzed by ANOVA followed by least significant difference test or by Student's 't' test for unequal variance when appropriate. A probability of at least P < 0.05 was considered statistically significant. RESULTS: The plant extract (500 and 700 µg/ml) significantly (P < 0.05) depressed and shifted the calcium concentration-response curves (1 × 10(-3)- 1 × 10(-1) M) to rightward similar to that of nifedipine. CONCLUSIONS: Bacopa monniera extract exhibited calcium channel blocking activity in guinea-pig tracheal smooth muscles that may rationalize its relaxant action on guinea-pig trachea and its traditional use in respiratory disorders.

Substituted urea derivatives: a potent class of antidepressant agents.

A series of fourteen (14) N-nitrophenyl-N'-(alkyl/aryl)urea and symmetrical 1,3-disubstituted urea derivatives were synthesized and evaluated for their antidepressant activity in mice. Among them, N-(4-nitrophenyl)-N'-(1'-phenylethyl)urea (1), demonstrated profound antidepressant property as reflected by significant reduction in the immobility time (89.83%), whereas compounds 2-6 showed activity values between 36 to 59% which were also larger than the standard phenelzine. Compounds 7-9 were less effective in reducing the immobility period of mice 26.20 to 31.01%). This variable magnitude of antidepressant activity appears to be related to the position of the nitro group to the parent molecules 1, 2, and 8. Compound 1 with the nitro group at para position showed to be the most effective antidepressant. However, the activity declined, if the nitro is attached to ortho and meta positions.

Comparison of monoamine reuptake inhibitors for the immobility time and serotonin levels in the hippocampus and plasma of sub-chronically forced swim stressed rats.

The current study was aimed at comparing the behavioral and biochemical (5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels) effects of monoamine reuptake inhibitors (fluoxetine, venlafaxine and imipramine) in sub-chronically forced swim stressed rats. At the given doses of 10, 20 and 30 mg/kg, among aforesaid antidepressants, the imipramine treatment alone caused significant decline in the immobility time of rats (IC(50) 20 mg/kg). In the hippocampus of rats, the imipramine treatment caused significant elevation of 5-hydroxytryptamine (5-HT) whereas, the fluoxetine and venlafaxine elicited significant increase in 5-hydroxyindoleacetic acid (5-HIAA) levels. Likewise, in the plasma of rats, the imipramine treatment significantly increased the 5-HIAA levels whereas, the fluoxetine and venlafaxine treatment significantly elevate the 5-HT levels. It can therefore be inferred that the imipramine did not act like other monoamine reuptake inhibitors in biochemical study, which could possibly underlie its ability to be detected in forced swim test (behavioral study). Moreover, the re-uptake inhibition of 5-HT is not accountable for the antidepressant action exhibited in forced swim test.

Forced swimming stress does not affect monoamine levels and neurodegeneration in rats.

OBJECTIVE: The current study was aimed to investigate the correlations between immobility time in the forced swimming test (FST, a behavioral indicator of stress level) and hippocampal monoamine levels (markers of depression), plasma adrenalin level (a peripheral marker of stress) as well as fluoro-jade C staining (a marker of neurodegeneration). METHODS: Male Sprague-Dawley rats were subjected to acute, sub-chronic (7 d) or chronic (14 d) FSTs and immobility time was recorded. Levels of noradrenalin, serotonin and dopamine in the hippocampus, and adrenalin level in the plasma were quantified by high-performance liquid chromatography with electrochemical detection. Brain sections from rats after chronic forced swimming or rotenone treatment (3 mg/kg subcutaneously for 4 d) were stained with fluoro-jade C. RESULTS: The rats subjected to swimming stress (acute, sub-chronic and chronic) showed long immobility times [(214 +/- 5), (220 +/- 4) and (231 +/- 7) s, respectively], indicating that the animals were under stress. However, the rats did not exhibit significant declines in hippocampal monoamine levels, and the plasma adrenalin level was not significantly increased compared to that in unstressed rats. The rats that underwent chronic swimming stress did not manifest fluoro-jade C staining in brain sections, while degenerating neurons were evident after rotenone treatment. CONCLUSION: The immobility time in the FST does not correlate with markers of depression (monoamine levels) and internal stress (adrenalin levels and neurodegeneration), hence this parameter may not be a true indicator of stress level.

Studies on anti-inflammatory and analgesic activities of betel nut in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Areca catechu, commonly known as betel nut, is very famous for its medicinal use in multiple disorders. It is also popular as a remedy against inflammatory disorders in the Unani (Greco-Arab) system of medicine. OBJECTIVE OF THE STUDY: This study was aimed at investigating the anti-inflammatory and analgesic activities of the crude extract of Areca catechu and its respective fractions. MATERIALS AND METHODS: Paw edema, formalin-induced nociception and acetic acid-induced writhing assays were carried out in vivo. Free radical scavenging activity of the plant extract was performed in vitro. RESULTS: Preliminary experiments using a single dose (100 mg/kg) of Areca catechu and its respective fractions demonstrated an anti-inflammatory effect on carrageenan-induced edema in mice and rats, the aqueous fraction being distinctly more effective. When studied on prostaglandin E2 (PGE2), arachidonic acid, histamine, or serotonin (5HT)-induced edema in rats, Areca catechu and its aqueous fraction markedly repressed only the PGE2 and arachidonic acid-induced inflammation. When studied for analgesic activity, the crude extract and its aqueous fraction produced a dose-dependent (10-100 mg/kg) inhibitory effect on formalin-induced nociception in mice and acetic acid-induced writhing in rats, similar to aspirin. In DPPH assay, Areca catechu and its aqueous fraction exhibited free radical scavenging activity with respective IC(50) values of 5.34 µg/ml (4.93-5.78, CI; 95%, n=5) and 7.28 µg/ml (6.04-7.95, n=4), like that of rutin with IC(50) value of 4.75 µg/ml (3.89-5.42, n=4). CONCLUSION: These results indicate the anti-inflammatory and analgesic effects of Areca catechu and provide a rationale for its medicinal use in inflammatory disorders.

Evaluation of antinociceptive effect of Aegiceras corniculatum stems extracts and its possible mechanism of action in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Aegiceras corniculatum (Linn.) Blanco is used in various traditional medicinal system(s) for the treatment of rheumatism, painful arthritis and inflammation. Therefore, the pharmacological studies of its antinociceptive effect was undertaken to validate its traditional use. MATERIALS AND METHODS: n-Hexane, ethyl acetate and methanol extract(s) derived from Aegiceras corniculatum (stems) were studied using various nociceptive model(s) induced chemically or thermally in mice including acetic acid-induced writhing, formalin-induced paw licking and hot plate test. RESULTS: In acetic acid-induced writhing test, plant extracts dose dependently decreased the writhing numbers. The methanolic extract (1-10mg/kg, i.p. in mice) of the plant was more potent than acetaminophen and acetyl salicylic acid, with an IC(50) of 4.2 ± 0.99 mg/kg. Moreover, the time of nociceptive behaviors induced by intraplantar formalin injection was also suppressed during 1st and 2nd phases in the presence of ethyl acetate extract whereas, n-hexane and methanolic extracts inhibited the paw licking in mice during the 1st (IC(50) 12 ± 0.76 mg/kg) and 2nd phases (IC(50) 3.8 ± 0.55 mg/kg). Naloxone, ß-funaltrexamine, and naltrindole antagonized the n-hexane extract-induced antinociception in the first phase of formalin test indicating its non-selective analgesic response via opioid receptor(s). However, ethyl acetate extract was devoid of any opioid action. Additionally, these extracts significantly inhibited the pain stimulation in hot plate test. Withdrawal syndrome of morphine dependence was also diminished in the presence of plant extracts via potentiation of GABAergic system. CONCLUSION: These results suggested that Aegiceras corniculatum extract(s) possesses analgesic properties and acts on the central nervous system, thereby suppressing the inflammatory pain justifying its folklore use.

Bioassay-guided isolation of antioxidant agents with analgesic properties from flowers of Tagetes patula.

CONTEXT: Tagetes patula L. is one of the French marigold group of the Asteraceae family. It is recognized in folklore for its medicinal and pesticidal properties. OBJECTIVE: In search of more effective, but non-toxic compounds with antioxidative potential led to the bioassay guided isolation studies on the extracts of T. patula. MATERIALS AND METHODS: The bioassay on Tagetes patula flowers were carried out guided by in vitro antioxidant activity using DPPH assay. A minor but proven plant constituent methyl protocatechuate (1) was isolated by column chromatography, while patuletin (2) and patulitrin (3) obtained in bulk by employing solvent partition of methanol extract. Derivatization of patuletin into benzoyl, cinnamoyl and methyl was conducted to establish the structure activity relationship (SAR). Analgesic activity of compound 2 was evaluated using acetic acid-induced writhing test and hot-plate test in mice. The toxicity of methanol extract and compound 2 were also determined. RESULTS: Polar extracts, fractions and phases demonstrated better antioxidant activity. The synthetic methyl protocatechuate (1) showed IC(50) value of 2.8 ± 0.2 µg/mL, whereas patuletin (2) (IC(50) = 4.3 ± 0.25 µg/mL) was comparable to quercetin and rutin but significantly better than patulitrin (3) (IC(50) = 10.17 ± 1.16 µg/mL). Toxicity test for the methanol extract and compound 2 did not elicit any behavioral changes or cause mortality in mice. Compound 2 also demonstrated mild analgesic property. DISCUSSION AND CONCLUSION: These findings demonstrate that the plant polar extracts and fractions possess significant antioxidant property with non-toxic effect. Compound 1 is a genuine plant constituent of T. patula.

Chlorinated and diepoxy withanolides from Withania somnifera and their cytotoxic effects against human lung cancer cell line.

Phytochemical studies on the aerial parts of Withania somnifera L. Dunal. (Solanaceae) led to the isolation of a chlorinated steroidal lactone (27-acetoxy-4ß,6α-dihydroxy-5ß-chloro-1-oxowitha-2,24-dienolide), a diepoxy withanolide (5ß,6ß,14α,15α-diepoxy-4ß,27-dihydroxy-1-oxowitha-2,24-dienolide), and withaferin A. Their structures were elucidated by using spectroscopic techniques. All three compounds exhibited a growth inhibition and cytotoxic activity against human lung cancer cell line (NCI-H460), with withaferin A being the most potent (GI(50)=0.18 µg/mL and LC(50)=0.45 µg/mL) among three compounds tested.

The antinociceptive activity of Polygonatum verticillatum rhizomes in pain models.

AIM OF THE STUDY: The current study was designed to establish the pharmacological rationale for the traditional use of the rhizomes of Polygonatum verticillatum in the treatment of painful conditions and as a plant diuretic. MATERIALS AND METHODS: The crude methanolic extract of the rhizomes of Polygonatumverticillatum (PR) was tested in various established pain models in rodents at 50, 100 and 200mg/kg i.p. while the diuretic activity was assessed at 300 and 600 mg/kg p.o. in rats. RESULTS: PR demonstrated significant reduction (14-72%) in the number of writhes induced by acetic acid in a dose-dependent manner. When nociceptive threshold was measured in the formalin test, PR strongly attenuated the formalin-induced flinching behaviour in both phases (6-30% in first phase while 12-72% in second phase). Central involvement in the analgesic profile of PR was confirmed by the hot plate test, in which PR elicited a significant (P<0.01) analgesic activity by increasing latency time. However, an opioid receptor antagonist, naloxone (2mg/kg s.c.) strongly antagonized the antinociceptive activity of PR. As a plant diuretic, PR showed mild but statistically insignificant diuretic activity at 300 mg/kg. The crude extract and solvent fractions of the plant contained reasonable quantity of total saponin and alkaloid contents. CONCLUSIONS: The mechanisms underlying the analgesic action of PR shows that the opioid dependant central mediation has synergistic effect by enforcing the peripheral analgesic effects. Interestingly, our findings not only substantiated the folk use of the plant as an analgesic but also reported for the first time in the whole genus.