Isolation and pharmacological activities of the Tecoma stans alkaloids

Tecoma stans is a plant traditionally used in Mexico for the control of diabetes. Amongst the alkaloids isolated from the plant harvested in Egypt, Tecomine was shown to be one of the compounds responsible for the hypoglycemic action. Given the interest in substances able to treat type II diabetes, we isolated the main alkaloids present in the plant growing in Egypt and Brazil and tested them in vivo on db/db mice. Contrary to previous literature reports on different animal models, Tecomine was unable to modify glycemia; the only effect seen being a decrease in plasma cholesterol levels. On the contrary, when tested in vitro on glucose uptake in white adipocytes, the compound showed a marked effect. The two other alkaloids isolated, namely 5beta-Hydroxyskitanthine, early called Base C, and Boschniakine were inactive both in vivo and in vitro assays.     

Characterization and pharmacological actions of tecostanine,an alkaloid of Tecoma stans

Tecostanine (1) was isolated from Tecoma stans leaves. Its sterochemistry was elucidated as well as its antihyperglycemic activity and its affinity to opioid and nicotinic receptors. The oxalate salt of 1 did not significantly affect blood glucose levels in normoglycaemic and hyperglycaemic rats. It did not appear to interact with opioid receptors (mu type) and showed only moderate affinity to the nicotinic receptor.     

Evaluation of antinociceptive and anti-inflammatory activity of hydromethanol extract of Cocos nucifera L.

Cocos nucifera L. (family: arecaceae) is generally straight unbranched plant, traditionally cultivated for its fruit (coconut) in home gardens. In the present study, anti-inflammatory and antinociceptive (analgesic) activity of hydromethanol extract of Cocos nucifera L. (HECN) was evaluated in animal models. HECN showed significant (p < 0.05) and dosedependent anti-inflammatory activity in carrageenan induced paw oedema models of inflammation and the result was comparable with the standard drug diclofenac. In addition, the extract also showed highly significant (p < 0.01) antinociceptive activity. HECN treated group showed increase in the reaction time in hot plate method and decrease the writhing induced by acetic acid in mice when compared with control group animal. The anti-inflammatory and antinociceptive activity observed in the present study could be attributed largely to the presence of its antioxidant phytoconstituents such as flavonoid, saponin and polyphenols.     

Anti-angiogenic, antinociceptive and anti-inflammatory activities of Lonicera japonica extract

This study aimed to elucidate some novel pharmacological activities of Lonicera japonica (Caprifoliaceae), which is widely used in Oriental folk medicine. The ethanolic extract of L. japonica (LJ) dose dependently inhibited chick chorioallantoic membrane angiogenesis. The antinociceptive activity of LJ was assessed using the acetic acid-induced constriction model in mice. LJ showed anti-inflammatory activity in two in-vivo models: the vascular permeability and air pouch models. LJ suppressed the production of nitric oxide via down-regulation of inducible nitric oxide synthase in lipopolysaccharide-stimulated RAW264.7 macrophage cells. However, LJ was unable to suppress induction of cyclooxygenase-2 in the stimulated macrophage cells. LJ decreased the reactive oxygen species level in the stimulated macrophage cells. In brief, the flowers of L. japonica possess potent anti-angiogenic and antinociceptive activities, in addition to anti-inflammatory activity, which partly supports its therapeutic efficacy.     

Evaluation of aqueous extract of Felicia muricata leaves for anti-inflammatory,antinociceptive, and antipyretic activities

Context: Felicia muricata Thunb. (Nees) (Asteraceae) leaves are used in folklore medicine of South Africa as an oral remedy for pain and inflammation. However, the efficacy of the plant part is yet to be validated with scientific experiments.

Objective: The current study is an effort to investigate the anti-inflammatory, antinociceptive, and antipyretic activities of aqueous extract of F. muricata leaves.

Materials and methods: The phytochemical screening of aqueous extract of Felicia muricata leaves and the efficacy of the extract at the doses of 50, 100, and 200?mg/kg body weight was investigated in experimental animals using several models of inflammation (paw edema induced by carrageenan and egg albumin), nociception (acetic acid-induced writhing, formalin-induced pain and tail immersion), and fever (brewer’s yeast-induced hyperthermia).

Results: The extract contained alkaloids, flavonoids, tannins, saponins, and phenolics. The extract dose-dependently reduced (P <0.05) the number of writhes and stretches induced by acetic acid, number of licks induced by formalin, paw volumes induced by carrageenan and egg albumin. The reaction time by the tail of the extract-treated animals to the hot water also increased. The extract also reduced hyperthermia induced by brewer’s yeast. The highest dose (200?mg/kg body weight of the extract) produced the best result in all cases.

Discussion and conclusion: This study revealed that the aqueous extract of Felicia muricata leaves possessed anti-inflammatory, antinociceptive and antipyretic activities. These findings have therefore supported the use of aqueous extract of Felicia muricata leaves in the traditional medicine of South Africa as an oral remedy for pains, inflammation, and fever.     

Evaluation of anti-inflammatory and antinociceptive activities of Murraya exotica

Context:?Leaves of Murraya exotica L. (Rutaceae) are used for the treatment of various disorders such as cough, fever, and infectious wounds, as well as alleviating pains in folk medicine in southern China.

Objective:?The objectives of this study were to investigate the in vivo antinociceptive and anti-inflammatory activities of ethanol (70%) extracts and isolated compounds obtained from the dried leaves of M. exotica.

Materials and methods:?The antinociceptive activities were evaluated with the methods of acetic acid-induced writhing response and hot-plate latent pain response test. Carrageenan induced hind paw edema, xylene induced ear edema, and a rat knee osteoarthritis model were employed to measure the anti-inflammatory activities. The compounds were isolated using column chromatography and thin-layer chromatography, and the structures identified by ¹H NMR, ¹³C NMR, MS, and IR.

Results:?The ethanol (70%) extracts significantly decreased in the acetic acid-induced writhing response; increased in hot-plate latency; suppressed xylene induced ear swelling and the carrageenan-induced paw edema effectively. In the rat knee osteoarthritis model, the treatment of the ethanol (70%) extracts resulted in a significant increase in the activity of superoxide dismutase, an inhibition on inducible nitric oxide synthase activity, and a decrease in the contents of interleukin-1β and tumor necrosis factor-α of the rat serum. Following this, we explored the components of the ethanol (70%) extracts and isolated six known coumarins, including murracarpin, which exhibited the most potential in antinociceptive and anti-inflammatory activities.

Discussion and conclusion:?M. exotica displayed remarkable antinociceptive and anti-inflammatory activities.     

Enhancement of anti-inflammatory and antinociceptive actions of red ginseng extract by fermentation

Objectives This work aimed to compare some pharmacological properties of red ginseng extract (RG) and fermented red ginseng extract (FRG). Methods Antinociceptive activity was analysed using the acetic acid‐induced abdominal constriction response. Anti‐inflammatory activity was evaluated using acetic acid‐induced vascular permeability and carrageenan‐induced inflammation in the air pouch, and analysed through the measurement of nitrite content in the lipopolysaccharide (LPS)‐stimulated macrophage cells. Anti‐angiogenic activity was determined using the chick chorioallantoic membrane assay. Key findings In‐vivo anti‐inflammatory activity of FRG was stronger than that of RG in two animal models, vascular permeability and air‐pouch models. In the vascular permeability model, the doses of RG and FRG required for half‐maximal inhibition (IC50) were 181 and 59 mg/kg, respectively. FRG exhibited significantly stronger antinociceptive activity than RG. In the acetic acid‐induced abdominal constriction response, the IC50 values of RG and FRG were 153 and 27 mg/kg, respectively. Although both RG and FRG were able to suppress production of nitric oxide in the LPS‐stimulated RAW264.7 macrophage cells, the suppressive activity of FRG appeared to be stronger than that of RG. However, RG and FRG showed similar anti‐angiogenic activity. Conclusions FRG possesses enhanced anti‐inflammatory and antinociceptive activity but similar anti‐angiogenic activity than RG.     

Study of anti-inflammatory and antinociceptive activity of hydroalcoholic extract of Schima wallichii bark

Hydroalcoholic extract of Schima wallichii Choisy. (Ternstroemiaceae) bark (HESW) was investigated for its anti-inflammatory, antinociceptive, and antipyretic activities. The anti-inflammatory effects of the HESW were assayed by using carrageenan and dextran (acute model) induced paw edema and cotton pellet granuloma assay (chronic model) in experimental rats. Oral administration of HESW at the doses of 150 and 300?mg/kg caused dose-dependent inhibition of carrageenan and dextran induced inflammation. HESW at the doses of 150 and 300?mg/kg caused significant dose-dependent reduction of the granuloma tissue formation in experimental rats. The extract at the oral doses of 50 and 100?mg/kg body weight exhibited significant central and peripheral analgesic activity in acetic acid induced writhing test and hot-plate test respectively in experimental mice. Treatment with HESW at the oral doses of 150 and 300?mg/kg body weight significantly reduced the yeast-provoked elevated body temperature in experimental rats in a dose-dependent manner.     

Evaluation of anti-inflammatory potential of Bergenia ciliata Sternb. rhizome extract in rats

The methanol extract of the rhizome of Bergenia ciliata Sternb. (Saxifragaceae) has been evaluated for anti-inflammatory potential using two acute rat models (carrageenan- and serotonin (5-HT)-induced rat paw oedema) and a chronic rat model (cotton pouch-induced granuloma). Phenylbutazone (100 mg kg(-1)), a non-steroidal anti-inflammatory agent, was used as a standard. The methanol extract (100, 200 or 300 mg kg(-1)) exhibited significant (P < 0.05) anti-inflammatory activity in all the animal models. At 300 mg kg(-1) the methanol extract exhibited maximum inhibition of 32.4+/-2.89% in carrageenan-induced rat paw oedema while the standard showed an inhibition of 44.1+/-2.7% after 3 h of drug treatment. In the serotonin-induced rat paw oedema model, 300 mg kg(-1) methanol extract suppressed oedema by 45.33+/-2.09%, whereas the standard produced an inhibition of 53.5+/-4.3%. In the cotton pouch granuloma model the methanol extract inhibited significantly (P < 0.001) the granuloma weight in a dose-dependent manner. In this model, 300 mg kg(-1) extract produced a maximum inhibition of 31.4+/-1.09% in granuloma weight compared with 41.1+/-1.32% reduction in granuloma weight for the standard. The methanol extract of B. ciliata exhibited significant anti-inflammatory potential at the dose levels examined.     

Pharmacological evaluation for anti-asthmatic and anti-inflammatory potential of Woodfordia fruticosa flower extracts

Context: Woodfordia fruticosa Kurz. (Lythraceae) flowers are ethnopharmacologically acclaimed in the Indian medicinal system to treat asthma.

Objective: To evaluate W. fruticosa flower extracts for anti-asthmatic effect.

Materials and methods: Ethyl acetate, acetone, methanol, and hydro-alcohol extracts of W. fruticosa flowers were obtained successively and standardized. Ability of extracts to stabilize free radicals and compound-48/80-induced mast cell degranulation was evaluated. In vitro anti-inflammatory potential of extracts at 100 and 200?µg/ml by membrane stabilization and in vivo inhibition of rat paw edema up to 5?h (100 and 200?mg/ml; p.o.) was evaluated. In vitro bronchorelaxant effect was examined against histamine- and acetylcholine (1?µg/ml; independently)-induced guinea pig tracheal contraction. Extracts were evaluated for bronchoprotection (in vivo) ability against 0.1% histamine- and 2% acetylcholine-induced bronchospasm in guinea pigs at 100 and 200?mg/ml; p.o.

Results: Standardization studies revealed that the methanol extract exhibited highest polyphenolic (62.66 GAE), and flavonoid (6.32 RE) content and HPLC fingerprinting confirmed the presence of gallic acid (R_t 1.383). IC₅₀ values for DPPH scavenging and metal chelation by the methanol extract were 40.42 and 31.50?µg/ml. Methanol and ethyl acetate extracts at 100?µg/ml exhibited 06.52 and 07.12% of histamine release. Methanol, ethyl acetate, and hydro alcohol extracts at 200?mg/kg demonstrated 32.73, 29.83, 26.75% and 32.46, 9.38, 26.75% inhibition of egg albumin and carrageenan-induced inflammation, respectively. Methanol extract exhibited 100% bronchorelaxation and 48.83% bronchoprotection.

Conclusion: Woodfordia fruticosa flower (WFF) extracts exhibited anti-asthmatic effect by demonstrating bronchoprotection, bronchorelaxation, anti-inflammatory, antioxidant, and mast cell stabilization ability.     

Evaluation of Caesalpinia bonducella flower extract for anti-inflammatory action in rats and its high performance thin layer chromatography chemical fingerprinting

Objective:

The study is aimed to evaluate anti-inflammatory activity of Caesalpinia bonducella Fleming (Caesalpiniaceae) flower extract (CBFE) and to study its effect on radiographic outcome in adjuvant induced arthritis and authentication by high performance thin layer chromatography (HPTLC) chemical fingerprinting.

Materials and Methods:

CBFE was administered orally (30, 100, and 300 mg/kg b.wt.) and tested for its anti-inflammatory activity in carrageenan-induced inflammation, cotton pellet induced chronic granulomatous inflammation and autacoids-induced inflammation. Effect on radiographic outcome was tested in adjuvant-induced arthritis. CBFE was HPTLC fingerprinted in suitable solvent system.

Result:

In carrageenan-induced inflammation, CBFE produced significant inhibition in edema volume at all the doses (30, 100 and 300 mg/kg b.wt.) and percentage of inhibition was 28.68, 31.00, and 22.48, respectively as compared to control at 5 h of its administration. In cotton pellet granuloma assay, CBFE significantly decreased the granuloma weight at 300 mg/kg dose level by 22.53%. CBFE (300 mg/kg) caused significant inhibition by 37.5, 44.44, and 35.29% edema volume, at ½, 1 and 3 h after 5-hydroxytryptamine injection, respectively. Radiographic score of animals treated with 300 mg/kg CBFE was significantly decreased when compared to arthritic control animals.

Conclusion:

The extract was found to possess significant anti-inflammatory activity. CBFE treatment improved the bony architecture in adjuvant-induced arthritis in rats. The developed HPTLC fingerprint would be helpful in the authentication of C. bonducella flower extract.KEY WORDS: 5-hydroxy tryptamine, Caesalpinia bonducella, carrageenan-induced inflammation, cotton pellet granuloma, high performance thin layer chromatography, radiography     

Evaluation of anti-inflammatory and antinociceptive effects of D-002 (beeswax alcohols)

D-002, a mixture of six higher aliphatic alcohols purified from beeswax, displayed anti-inflammatory effects in carrageenan-induced pleurisy and cotton pellet granuloma in rats. The aim of the present study was to confirm the anti-inflammatory properties of D-002 and to explore its potential analgesic effects. Xylene-induced mouse ear oedema was used to assess the anti-inflammatory effect, acetic acid-induced writhing and hot plate responses for the analgesic activity, and the open field and horizontal rotarod tests for motor performance. For anti-inflammatory tests, mice were randomised into a negative vehicle control and five xylene-treated groups: the vehicle, D-002 (25, 50 and 200 mg/kg) and indomethacin 1 mg/kg (reference drug). Treatments were given for 15 days. Effects on oedema formation and myeloperoxidase (MPO) activity were tested. For analgesia and motor performance tests, mice were randomised into a vehicle control and D-002-treated groups (25, 50 and 200 mg/kg). Two sets of experiments were done, which included acute and repeat (15 days) dosing. D-002 (25, 50 and 200 mg/kg) significantly decreased xylene-induced ear oedema (44.7, 60.8 and 76.4%, respectively) and the increase of MPO activity induced by xylene (38.0, 47.0 and 57.0%, respectively), while indomethacin significantly inhibited xylene-induced oedema (59.9%) and MPO activity (57.5%). Single and repeat doses of D-002 (25, 50 and 200 mg/kg) decreased the acetic acid-induced writhing responses by 21.2, 28.2 and 40.1%, for the single doses; 25.2, 35.1 and 43.2%, respectively, for the repeat doses, but did not affect the hot plate, open field and rotarod behaviours. Aspirin 100 mg/kg significantly decreased acetic acid-induced abdominal constrictions and morphine (5 mg/kg) significantly increased the latency of the hot plate response. This study confirmed the anti-inflammatory effects of D-002 and demonstrated its analgesic effects on the acetic acid-induced writhing, but not on the hot plate response, which suggests that the antinociceptive effects of D-002 could be related to its anti-inflammatory activity.     

In-vitro and in-vivo anti-inflammatory and antinociceptive effects of the methanol extract of the roots of Morinda officinalis

The anti-inflammatory effects of the methanol extract of the roots of Morinda officinalis (MEMO) (Rubiaceae) were evaluated in-vitro and in-vivo. The effects of MEMO on lipopolysaccharide (LPS)induced responses in the murine macrophage cell line RAW 264.7 were examined. MEMO potently inhibited the production of nitric oxide (NO), prostaglandin E2 and tumour necrosis factor-alpha (TNF-alpha) in LPS-stimulated RAW 264.7 macrophages. Consistent with these results, the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level, and of iNOS, COX-2 and TNF-alpha at the mRNA level, was also inhibited by MEMO in a concentration-dependent manner. Furthermore, MEMO inhibited the nuclear factor kappa B (NF-kappaB) activation induced by LPS, and this was associated with the prevention of degradation of the inhibitor kappaB (IkappaB), and subsequently with attenuated p65 protein in the nucleus. The anti-inflammatory effect of MEMO was examined in rats using the carrageenan-induced oedema model. The antinociceptive effects of MEMO were assessed in mice using the acetic acid-induced abdominal constriction test and the hot-plate test. MEMO (100, 200 mg kg-1 per day, p.o.) exhibited anti-inflammatory and antinociceptive effects in these animal models. Taken together, the data demonstrate that MEMO has anti-inflammatory and antinociceptive activity, inhibiting iNOS, COX-2 and TNF-alpha expression by down-regulating NF-kappaB binding activity.     

Methanol extract from mycelium of endophytic fungus Rhizoctonia sp. induces antinociceptive and anti-inflammatory activities in mice

The present study aimed to elucidate the antinociceptive and anti-inflammatory properties of the methanol extract from the mycelium of the endophytic fungus Rhizoctonia sp. (MEMRh) in mice. The antinociceptive activity was assessed using the abdominal constriction, hot plate, and formalin tests. The anti-inflammatory activity was assessed using a murine model of paw edema. Intraperitoneal administration of MEMRh (0.1, 1, 10 and 100?mg/kg, i.p.) produced an inhibition of acetic acid-induced writhing in mice for at least 8?h. In addition, all doses tested of the methanol extract were able to prevent thermal nociception in the hot-plate test. Furthermore, treatment with MEMRh (10?mg/kg, i.p.) inhibited both the early and late phases of formalin-induced nociception. This antinociceptive effect exhibited by MEMRh in the formalin test was reversed by the systemic administration of naloxone. MEMRh produced inhibition in a carrageenan-induced edema model at a dose of 10?mg/kg. The same extract also displayed significant activity against a histamine- or PGE(2)-induced edema model. The experimental data demonstrated that MEMRh showed remarkable anti-inflammatory and antinociceptive activities. Further studies are warranted to define and isolate the active anti-inflammatory and antinociceptive components from this endophytic fungus, which may yield effective agents for the treatment of inflammatory disorders.     

Evaluation of antinociceptive effects of Galipea longiflora alkaloid extract and major alkaloid 2-phenylquinoline

The present study evaluated the antinociceptive properties of an alkaloid extract and 2-phenylquinoline obtained from the bark of Galipea longiflora Krause (Rutaceae) against different models of pain in mice. The results demonstrate that the alkaloid extract caused a pronounced antinociceptive effect with the main alkaloid detected, 2-phenylquinoline, exhibiting moderate activity. The alkaloid extract had a calculated ID50 value of 20.3 mg/kg i.p. and less than 50 mg/kg p.o. against the writhing test which proved to be more effective than the reference drugs when administered by both routes. The ID50 of 2-phenylquinoline was 52.8 mg/kg i.p. with an inhibition of 24.5% when administered orally at 100 mg/kg. In the formalin test the alkaloid extract, but not 2-phenylquinoline, significantly inhibited both phases of pain (neurogenic and inflammatory) at 10 mg/kg i.p. with inhibitions of 37.4% and 58.3%, respectively. The alkaloid extract and 2-phenylquinoline caused only a modest effect in the capsaicin and glutamate tests. In the hot plate test, the alkaloid extract increased the latency time by 25.6% at 10 mg/kg i.p. compared to 2-phenylquinoline which was less effective. It appears that the antinociceptive effects of this plant may be attributed, at least in part, to the presence of some antinociceptive alkaloids in minor concentrations.     

Antioxidant, anti-inflammatory and analgesic potential of the Citrus decumana L. peel extract

The present study was designed to investigate the antioxidant, anti-inflammatory and analgesic potential of Citrus decumana peel extract. Antioxidant activity of Citrus decumana peel extract in four solvent systems was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH^·) and hydrogen peroxide (H₂O₂) radical scavenging methods. Ethyl acetate peel extract of Citrus decumana (EtCD) was studied for its anti-inflammatory and analgesic activities at a dose level of 100, 200 and 300 mg/kg. Anti-inflammatory activity was performed using carrageenan-induced paw edema in rats. Analgesic activity was evaluated for its central and peripheral pharmacological actions in mice. EtCD showed significant antioxidant activity in a dose-dependent manner when compared with ascorbic acid. EtCD at the dose of 300 mg/kg produced significant decrease in paw volume and pain when compared with reference drug diclofenac and morphine, respectively. The Citrus decumana peel extract may be useful as a natural antioxidant in the treatment of inflammation and pain.     

Evaluation of the antinociceptive and anti-inflammatory effects of essential oil of Nepeta pogonosperma Jamzad et Assadi in rats

Background and the purpose of study

Concerning the different effects of essential oils from Nepeta genus on the central nervous system including pain killing effect, this study was designed to evaluate the antinociceptive and anti-inflammatory effects of essential oil of Nepeta pogonosperma Jamzad et Assadi (NP), a recently identified species.

Methods

Air-dried aerial parts of NP were hydrodistillated and GC-MS analysis of obtained essential oil was conducted. Total 24 male Wister rats weighing 225 ± 25 gm were studied. Essential oil of NP was administered intraperitoneally at the doses of 50 mg/kg, 100 mg/kg and 200 mg/kg for the experimental groups. Control rats received equal volume (2 ml/kg) of normal saline. Antinociception was assessed by tail flick test (after 30 minutes) and formalin test (for further 60 minutes). Then the animal was sacrificed and the paw edema was measured using a water plethysmometer.

Results

4aα,7α,7aβ-nepetalactone and 1,8-cineole were found as the main concentrated components of NP essential oil. All the doses of NP showed antinociception. NP 200 mg/kg reduced the pain sensation in tail flick (p <0.01) and formalin test (p <0.001 in both phases). In paw edema test, NP 100 and 200 mg/kg significantly reduced the inflammation (p <0.01 and p <0.05).

Conclusion

This study reveals that the essential oil of NP may minimize both the acute and chronic forms of nociception and may have potent role against inflammation, but the dose should be maintained precisely to obtain the intended effect.     

Antioxidant,anti-inflammatory,and antinociceptive activities of Turkish medicinal plants

Hypericum orientale L. (Hypericaceae), Helichrysum plicatum Dc. subsp. plicatum (Asteraceae), Centaurea drabifolia Sm. subsp. drabifolia (Asteraceae), Centaurea drabifolia Sm. subsp. detonsa (Bornm.) Wagenitz (Asteraceae), Achillea wilhelmsii C. Koch (Asteraceae), and Rubus canescens Dc. var. canescens (Rosaceae) are used for the treatment of hemorrhoids, abdominal pains, and wound healing in traditional Turkish medicine. In order to assess these uses, methanol extracts prepared from their aerial parts were investigated for antioxidant, anti-inflammatory, and antinociceptive activities. All extracts demonstrated scavenging properties against superoxide anion (O₂^?–) and hydrogen peroxide (H₂O₂) in a non-cellular system, and toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. They also inhibited Cu²⁺-induced low-density lipoprotein (LDL) peroxidation. Among the tested plants, R. canescens var. canescens, H. orientale, and H. plicatum subsp. plicatum were the most effective on ROS in a non-cellular system. Another goal in this work was to test in vivo anti-inflammatory and antinociceptive activities of some of these plants not previously studied. The methanol extracts of C. drabifolia subsp. drabifolia, H. orientale, and C. drabifolia subsp. detonsa were shown to possess significant inhibitory activity in mice against carrageenan-induced hind paw edema and in p-benzoquinone-induced writhings.     

Bioassay-guided isolation of anti-inflammatory and antinociceptive compound from Plumbago zeylanica leaf

Plumbago zeylanica Linn. (Plumbaginaceae) is used in the treatment of various inflammatory ailments in traditional medicines. In order to validate these ethnobotanical practices, the anti-inflammatory and antinociceptive activities of various leaf extracts (petroleum ether (60–80°), chloroform, acetone, ethanol, and aqueous) were studied using in vivo experimental models at two dose levels (200 and 400?mg/kg, p.o.). Anti-inflammatory activity was tested using the carrageenan induced rat hind paw edema method while analgesic activity was studied using the hot plate and formalin induced models. Diclofenac (100?mg/ kg) was used as the reference standard in both anti-inflammatory and analgesic models and morphine (10?mg/ kg, i.p.) was used as the reference standard in the formalin induced analgesic model. The acetone extract significantly (p?<?0.01) reduced inflammation in the rats when compared to the control group. As for the analgesia effect, the acetone and petroleum ether extracts significantly (p?<?0.01) decreased the pain stimulus only in the later phase of the formalin test, suggesting that the drug could be peripherally acting. Bioassay-guided fractionation of the acetone extract led to the isolation and identification of plumbagin. Structure elucidation of plumbagin confirmed it as 5-hydroxy-2-methyl-1,4-naphthoquinone, a naphthaquinone derivative, through spectral techniques.