Analgesic and anti-inflammatory effects of ethanol extracted leaves of selected medicinal plants in animal model -

Aim: The research was carried out to investigate the analgesic and anti-inflammatory effects of ethanol extract of Desmodium pauciflorum, Mangifera indica and Andrographis paniculata leaves. Materials and Methods: In order to assess the analgesic and anti-inflammatory effects acetic acid induced writhing response model and carrageenan induced paw edema model were used in Swiss albino mice and Wistar albino rats, respectively. In both cases, leaves extract were administered (2gm/kg body weight) and the obtained effects were compared with commercially available analgesic and anti-inflammatory drug Dclofenac sodium (40mg/kg body weight). Distilled water (2ml/kg body weight) was used as a control for the study. Results: In analgesic bioassay, oral administration of the ethanol extract of leaves were significantly (p<0.01) reduced the writhing response. The efficacy of leaves extract were almost 35% in Desmodium pauciflorum, 56% in Mangifera indica and 34% in Andrographis paniculata which is found comparable to the effect of standard analgesic drug diclofenac sodium (76%). Leaves extract reduced paw edema in variable percentages but they did not show any significant difference among the leaves. Conclusion: We recommend further research on these plant leaves for possible isolation and characterization of the various active chemical substances which has the toxic and medicinal values.


Introduction
region which has been used in traditional system in Indian sub-continent medicine as antiemetic and anti-Medicinal plants are of great importance to the inflammatory drugs.Mangifera indica grows in the health of individuals and communities.The medicinal tropical and subtropical region and its parts are value of these plants lies in some chemical active commonly used in folk medicine for a wide variety of substances that produce a definite physiological action remedies [6,7].Andrographis paniculata commonly on the human body.The most important of these known as Kalmegh in Bangladesh is widely used in chemically active constituents of plants are alkaloid, traditional system in Indian medicine.The pharmacotannin, flavonoid and phenolic compounds.Many of logical properties of the Kalmegh showed varying the indigenous medicinal plants are used for medicinal degrees of analgesic, anti-pyretic and anti-inflammatory purposes [1].In the last few years, a number of studies activities [8,9].Drugs which are used presently for the have been conducted in different medicinal plants in management of pain and inflammatory conditions are different countries to prove the medicinal efficiency [2-either steroidal (corticosteroids) or non steroidal 5].Plants are rich in a wide variety of secondary (aspirin).All of these drugs possess toxic effects at metabolites, such as tannins, terpenoids, alkaloids, and variable level like renal failure, allergic reactions, and flavonoids, which have been found in vitro to have occasionally hearing loss, and they can increase the medicinal properties.The advent of science into the risk of hemorrhage by affecting platelet function [10].search for antibiotics largely depends on some of these The risk of death as a result of use of NSAIDs is 1 in medicinal plants as raw materials.For many years, 10,000 for young adults aged 16-45 and the risk medicine had depended exclusively on leaves, flowers increases tenfold for those over 75 years old [11].Moreover and barks of plants; only recently have synthetic drugs synthetic drugs are very expensive to develop [11].On come into use.At present nearly 30% or more of the the contrary many medicines of plant origin had been modern pharmacological drugs are derived directly or used since long time without any adverse effects.It is indirectly from plants and in homeopathic or ayurvedic therefore essential that efforts should be taken to medicines, medicinal plants, their parts and extracts develop new drugs of plant origin that possess antidominate the scenes.
nociceptive and anti-inflammatory effects which will Desmodium pauciflorum is a small shrub of tropical be economically feasible, as well as contains lesser side group received analgesic drug diclofenac sodium at the effects.
dose rate of 40mg/kg body weight and treated group In Bangladesh, very few works have been done to received leaves extract at the dose rate of 2gm/kg body explore the possibilities of utilizing the locally available weight.Ethanol extract leaves, analgesic drug diclofenac herbs and shrubs in veterinary practice.Keeping these sodium and distilled water were administered orally to views in mind, the present work was designed to particular groups, 30 min prior to acetic acid injection.investigate the analgesic and anti-inflammatory activities 1 % acetic acid solution at the dose rate of 3.3ml/kg of selective available plants in Bangladesh.
body weight was injected intra-peritoneally in mice and the number of writhing and stretching was counted and Andrographis paniculata were collected from Chittagong, Bangladesh.The fresh leaves obtained

Assay of anti-inflammatory activity of plant extract:
Carrageenan induced paw edema model described by were washed with fresh water immediately after collection.
Winter et al., [13] was used for evaluating potential Leaves were then chopped into small pieces, air-dried at room temperature for 10 days.Dried leaves were anti-inflammatory activities by leaves extract.ground into powder and stored in an airtight container.
Carrageenan induced paw edema model: Fifteen After that 750gm powder from each leaves were taken Wistar albino rats were randomly divided into three and suspended in 5L ethanol for 7 days at room groups and each group consisting of 5 animals.Control temperature.Ethanol extract was sieved using cotton group received only distilled water, positive control plug followed by a Whatman no.1 filter paper.The group received commercially available analgesic drug extract was concentrated under reduced pressure below diclofenac sodium at the dose rate of 40mg/kg body 50ºC through rotatory vaccum evaporator.The concenweight and treated group received leaves extract at the trated extracts were collected in a Petri dish and dose rate of 2gm/kg body weight.Leaves extract, diclofenac allowed to air-dry for complete methanol evaporation.
sodium and distilled water were administered orally to Finally, 50gm greenish colored, concentrated leaves each group (1hr) one hour prior to the sub-plantar extract was obtained from each leaves and kept them in injection of carrageenan.Initially the right hind paw volume fridge (4ºC).
of each rat was measured using plethysmometer (UGO Experimental animals and diets: Swiss albino mice of Basile, Italy) and then 0.1ml of 1% carrageenan was both sexes weighing between 25-30g and Wistar injected subcutaneously into the sub-plantar region of Albino rats of the either sex weighing between 150the right hind paw to induce acute inflammation.The to control rats at time t.(Ct -Co) treated is edema or (COX) enzyme [19].The results support the popular The results suggested ethanol extract leaves and use of mentioned plant leaves extract, but Diclofenac sodium had analgesic action and showed phytochemical studies together with pharmacological significant (p<0.01)reduction of pain in comparison and toxicological investigations have proven essential with control group.Mangifera indica had higher for the complete understanding of their medicinal analgesic activity (56%) than other leaves extract (34application.35%).
Anti-inflammatory activity: In the present study, the Anti-inflammatory activity: Table-2 showed that the anti-inflammatory effects of the ethanol extract of paw edema were significantly (p<0.05 and p<0.01) leaves were demonstrated in an in vitro animal model, nd rd lees in 2 and 3 hours in both ethanol extracted leaves which focused on the inhibitory effect of the extract on and diclofenac sodium in comparison with control anti-inflammatory activity.Inflammation can be st th group.On the other hand 1 and 4 hours there were no defined as the response of living tissues to injury which significant variation of paw edema among the treated involves a complex array of enzyme activation, and control animals.Among the extract of leaves of mediator release, and extravasations of fluid, cell Desmodium pauciflorum, Mangifera indica and migration, tissue breakdown and repair [20].The anti-Andrographis paniculata the anti-inflammatory inflammatory effects may be elicited by a variety of st nd rd th effects at 1 hr, 2 hr, 3 hr and 4 hr were 38%, 40%, chemicals agents and that there is no remarkable 32%, 33% and 21%, 35%, 37%, 29% and 21%, 38%, correlation between their pharmacological activity and 39%, 34% respectively.The overall anti-inflammatory chemical structure [21].We evaluate the antiactivity was highest in leaves extract of Desmodium inflammatory activity of ethanol extracted leaves of pauciflorum followed by Andrographis paniculata and Desmodium pauciflorum, Mangifera indica and Mangifera indica.
Andrographis paniculata by Carrageenan induced paw Discussion edema model which is an established model for evaluating anti-inflammatory activity.Development Analgesic activity: The writhing test has long been of edema in the paw of rats after injection of used as a screening tool for the evaluation of analgesic carrageenen is a biphasic event [22].The initial phase properties of new substances.Ethanol extracted leaves observed during the first hour is attributed to the release of Desmodium pauciflorum, Mangifera indica and of histamine and serotonin.The second phase of edema Andrographis paniculata showed significant inhibition is due to the release of prostaglandins, protease, and (p<0.01) of acetic acid induced writhing response of lysosome [23][24][25].A significant anti-inflammatory mice, so it can be suggested that those leaves extract effect was showed in leaves extract of Abies pindrow has potential analgesic activities.The analgesic effect Royle, and the highest dose being comparable to of the extract may be either due to its action on visceral phenylbutazone [26] in the carrageenin induced paw receptor sensitive to acetic acid, to the inhibition of the edema in rats.Our findings not only provided algogenic substances or the inhibition of transmission experimental evidence for an anti-inflammatory of painful messages at the central level [14,15].The mechanism but were also beneficial to future research special nerve endings that sense pain are very sensitive also anti-inflammatory effect.However, further period.Finally, % analgesic activity Sample collection and leaves extract preparation: The was calculated by using following formula-% Analgesic activity = Mean writhing count (Control group-leaves of Desmodium pauciflorum, Mangifera indica Treated group) / Mean writhing count of control group x 100

5 ( 3 (
st nd rd 200g obtained from Chittagong, BCSIR laboratories, volume of right hind paw was measured at 1 , 2 , 3 th were used for the experiment.The animals were and 4 hour after carrageenan injection.The antiacclimatized to room temperature (28±5°C) with a inflammatory activity was calculated according to the relative humidity (55±5%) in a standard wire meshed following formula-Anti-inflammatory activity (%)= (Ct -Co) control -(Ct -Co) treated / plastic cages under a 12 h light/12 h dark cycle for 4-Ct -Co) control x 100 days prior to the experiment.The animals were Where Ct is the right hind paw thickness volume supplied with standard pellet diet prepared by BCSIR in mm ) at time t, Co is the right hind paw thickness and adlibitum water.Laboratory experimentation was 3 volume (in mm ) before carrageenan injection.(Ct -Co) performed according to the guidelines of Institutional control is edema or paw size after carrageenan injection Animal Ethics Committee (IAEC) of BCSIR.
The abdominal injection of acetic acid in mice has extract of Desmodium pauciflorum, Mangifera indica been attributed to the release of arachidonic acid, which and Andrographis paniculata reduced the writhing results synthesis of prostaglandin via the cyclooxygenase count from 66.7 to 43.5, 29.5 and 44.2, respectively.
Koster et al., [12]was performed to evaluate the analgesic Statistical analysis: The obtained information was activities of leaves extracts.imported,sortedand coded accordingly using Acetic acid induced writhing response model: FifteenMicrosoft Excel-2000.The data was exported from Swiss albino mice were randomly divided into three MS Excel-2000 to STATA/IC-11 for analysis.The groups and each group consisting of 5 animals.Control results were expressed as mean and standard error of group received only distilled water, positive control mean.Statistical significance between the groups was