compare the anti-inflammatory activity of aloe vera with a standard Anti-inflammatory drug indomethacin in acute and

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1 ISSN: X CODEN: IJPTFI Available Online through Research Article EVALUATION OF ANTI-INFLAMMATORY ACTIVITY OF ALOE VERA IN ALBINO RATS Dr. Bhuvana K.B.M.B.B.S., M.D, and Dr. Hema N.G. M.B.B.S., M.D Department of Pharmacology, Shridevi Institute of Medical Sciences and Research Hospital, Tumkur Department of Pharmacology, Mysore Medical College and Research Institute, Irwin Road, Mysore. Received on Accepted on Abstract Objectives: The purpose of the study was to evaluate the anti-inflammatory activity of aloe vera in albino rats and to compare the anti-inflammatory activity of aloe vera with a standard Anti-inflammatory drug indomethacin in acute and chronic inflammatory models. Methods: Anti inflammatory Models used in the present study were carrageenan induced rat paw edema and Cotton pellet induced Granuloma Model. The animals were randomly divided into 3 groups of 6 each. One group would serve as control and would receive 2% gum acacia suspension orally (without drug). Other two groups would receive drug indomethacin and Aloe vera extract orally. Each rat was fed with respective drug, Anti-inflammatory activity was expressed as Percent inhibition (PI). Statistical analysis was performed using One-way analysis of variance (ANOVA) followed by Scheffe s post hoc test. P < 0.05 was considered statistically significant. Results: The PI with indomethacin and Aloe vera in carrageenan induced paw edema were % and % and in cotton pellet induced granuloma were % and % respectively. Indomethacin and Aloe vera showed significant anti-inflammatory activity in both the models. Conclusion: The result in this study suggests that aqueous extract of Aloe vera has anti-inflammatory activity comparable to standard drug indomethacin. Aloe vera, thus can be a promising anti-inflammatory agent. Key Words: Anti-inflammatory; Aloe vera; Indomethacin; Carrageenan; Cotton pellet. IJPT July-2013 Vol. 5 Issue No Page 5610

2 Introduction Dr. Bhuvana* et al. International Journal Of Pharmacy & Technology Pain and inflammation are disabling accompaniments of many medical illnesses. So, control of both pain and inflammation assumes top priority for the physician.inflammation is a pathophysiological response of living tissues to injuries that leads to local accumulation of plasmatic fluids and blood cells. Though it is a defense mechanism, the complex events and mediators involved in the inflammatory reaction can induce, maintain or aggravate many diseases. 1 Both acute and chronic inflammatory diseases are still one of the most important health problems in the World. Therapy of inflammation is a debate and is also incomplete since long.the nonsteroidal antiinflammatory drugs are among the most widely prescribed and used drugs in the community for rheumatologic as well as nonrheumatologic conditions, which include acute and chronic pain; biliary, ureteric colic; dysmenorrhoea; fever; and other applications that derive from the suppression of prostaglandin synthesis. 2 An estimated hundred million prescriptions of NSAIDs are written yearly all over the world. Even two decades earlier the worldwide number of prescriptions issued in 1989 was 458 million. 3 Patients using NSAIDs are three times more likely to develop upper gastrointestinal bleeding than those not taking NSAIDs. The risk of bleeding increases with incremental doses of NSAIDs, especially ibuprofen, diclofenac and piroxicam. In addition to gastroduodenal mucosal damage, NSAIDs may also induce distal small and large intestinal injuries. The ileocecal region in particular, is a potential site for injuries such as erosions, ulcers, strictures and perforations. NSAIDs may also activate a quiescent colitis or even induce inflammatory bowel disease. 3 Concerns were raised regarding adverse cardiovascular events of selective COX-2 inhibitors inspite of their initial success. 4 Most people in rural areas of the World depend largely on herbs for the treatment of several ailments. This is because medicinal herbs constitute indispensable components of traditional medicinal practice due to low cost, easy access and ancestral experience. Medicinal herbs and plant extracts are now generally considered as effective medicines to be respected, appreciated and they play a major role in modern pharmacy. World Health Organization estimated that about 80% of the world's population relies on herbs for their primary healthcare needs. 5 Aloe is also popular in both traditional Chinese and Ayurvedic medicine. The Chinese describe aloe's skin and the inner lining of its leaves as a cold, bitter remedy which is used to clear constipation due to accumulation of heat 6 ; the gel is IJPT July-2013 Vol. 5 Issue No Page 5611

3 considered cool and moist. In Ayurvedic medicine, the traditional medicine of India, aloe is used internally as a laxative, antihelminthic, hemorrhoid remedy and uterine stimulant (menstrual regulator); it is used topically, often in combination with licorice root, to treat eczema or psoriasis. In Arabian medicine, the fresh gel is rubbed on the forehead as a headache remedy or rubbed on the body to cool it in case of fever, as well as being used for wound healing, conjunctivitis and as a disinfectant and laxative. 7 Here an attempt has been made to explore its antiinflammatory activity. Material and Methods Materials Preparation of Extract The Aqueous extract of Aloe vera was obtained from Himalaya drug company. The leaves of Aloe vera were washed to remove dirt and impurities. Some of the leaves were dried for two weeks under low sun intensity, crushed in a mortar and further ground into a coarse powder. Then four times demineralised water was transferred with respect to quantity of the Raw Herb (twice). Extraction was done at o C for 3 hrs in a Soxhlet s apparatus. It was then filtered and was concentrated at o C up to 25% solids. It was later spray dried (inlet temperature 180 o C and outlet temperature 100 o C) and was packed in a double lined poly bag 8. Chemicals Indomethacin,Carrageenan (Sigma) and all other chemicals were of analytical grade. Animals Albino rats, of either sex, weighing g, were used for the study. The rats were inbred in the central animal house of the Department of Pharmacology, Mysore Medical College & Research Institute, Mysore.Animals were housed in groups of 3, at an ambient temperature of 25±1 C with ad libitum access to food and water. The study protocol was approved by Institutional Animal Ethics Committee. Methods Animals were randomly divided into 3 groups of 6 rats each; I group: Control (1ml of Vehicle, 2% Gum acacia suspension); II group: Standard drug (Indomethacin 10mg/kg); III group: Test drug (Aloe vera 25 mg/kg). IJPT July-2013 Vol. 5 Issue No Page 5612

4 Following models were used to screen the antiinflammatory activity of Aloe vera. Carrageenan Induced Rat Paw Edema Animal Model 9,10 In this method, rats were divided in 3 groups of six animals each. The animals were pretreated with drugs orally 1 hr before the experiment ml of 1% carrageenan was injected aseptically into the subplantar surface of right hind paw of each rat. Paw edema was measured by Mercury Plethysmograph at 0 hour 1 hour 2 hour 3 hour and 4 hours. The difference between the zero and 4 hours gives the actual edema. Percentage inhibition (protection) against edema formation was taken as an index of acute anti-inflammatory activity. It was calculated by: The percent inhibition of edema = 100 x (1- Vt / Vc) Where, Vc = mean paw edema volume in the control group. Vt = mean paw edema volume in the drug treated group. Cotton Pellet Induced Granuloma Animal Model 9,11 This is an established animal model to screen the chronic anti-inflammatory activity of the drugs. All the drugs were administered orally 1hr prior to the cotton pellet implantation on the first day, and later on, once daily for six consecutive days. The rats were anaesthetized lightly with ether and small linear incisions of about 1 cm were made in each axilla and groin under aseptic precautions. The sterile cotton wool pellets weighing 10mg each were implanted in these areas (4 pellets in each rat) and the wounds were sutured with black silk thread with aseptic precaution. The animals were maintained in clean cages and the food and water were allowed throughout the period of experimentation. Later the animals were sacrificed on the 8 th day and the cotton pellets with granulation tissue were removed, cleaned of the extraneous tissue. The moist pellets were weighed 12 and then dried in a hot air oven to a constant weight, dried pellets were weighed again.the dry weight of the granuloma (i.e. the amount of actual granulation tissue formed) was calculated by noting the difference in the dry weight of the cotton pellets recorded before and after implantation. Percent anti-granuloma activity = 100(1-Wt/Wc) Where, Wt= mean dry weight of granuloma in drug treated group Wc= mean dry weight of granuloma in drug untreated control group. IJPT July-2013 Vol. 5 Issue No Page 5613

5 Statistical Analysis Dr. Bhuvana* et al. International Journal Of Pharmacy & Technology Results were expressed as mean ± Standard deviation (SD). Statistical analysis was performed using One-way analysis of variance (ANOVA) followed by Scheffe s post hoc test. P <0.05 was considered statistically significant. All the statistical methods were carried out through the SPSS for Windows (version 16). Results Carrageenan-Induced Rat Paw Edema The aqueous extract of Aloe vera (25mg/kg) and indomethacin (10mg/kg) both significantly inhibited carrageenan induced rat paw edema (P < 0.05). The maximum inhibition of paw edema was observed in both indomethacin and Aloe vera at the end of four hours when compared to the control group. Antiinflammatory activity is expressed as Percent Inhibition (PI). The PI with Aloe vera and indomethacin were % and % respectively [Table 1and 2 and Figure 1]. Cotton Pellet Induced Granuloma The aqueous extract of Aloe vera(25mg/kg) and indomethacin (10mg/kg) both showed significant (P < 0.05) antiinflammatory activity in granuloma induced by cotton pellets. The PI with Aloe vera and indomethacin were % and % respectively [Table 3 and 4 and Figure 2]. Table-1: Effect of Aqueous extract of Aloe vera in Carrageenan induced paw edema 0hr to 3hr(cm) during the study. Groups N Mean paw edema(cm) ±SD PI (%) I. Control (1ml of vehicle) ± % II. Indomethacin (10mg/kg) ±1.336* % III. Aloe vera (25mg/kg) ±1.407* % IJPT July-2013 Vol. 5 Issue No Page 5614

6 Table-2: Effect of Aqueous extract of Aloe vera in Carrageenan induced paw edema 0hr to 4hr (cm) during the study. Groups N Mean paw edema (cm) ±SD PI (%) I. Control (1ml of vehicle) ± % II. Indomethacin (10mg/kg) ± % III. Aloe vera (25mg/kg) ± % Table-3: Effect of Aqueous extract of Aloe vera in Cotton pellet granuloma model during the study. Groups N Mean wet granuloma weight (mg) ±SEM PI (%) I. Control (1ml of vehicle) ± % II. Indomethacin (10mg/kg) ± % III. Aloe vera (25mg/kg) ± % Table-4: Effect of Aqueous extract of Aloe vera in Cotton pellet granuloma model during the study. Groups N Mean dry granuloma weight (mg) ±SEM PI (%) I. Control (1ml of vehicle) ± % II. Indomethacin (10mg/kg) ± % III. Aloe vera (25mg/kg) ± % IJPT July-2013 Vol. 5 Issue No Page 5615

7 Figure-1: Bar diagram showing the Mean paw volume (cm) at 0 hr and 4 hr - Carrageenan induced rat paw oedema Model 20 Mean Paw Oedema (cm) Hr 1 hr 2 hr 3 hr 4 hr Ctrl Standard Test Duration Figure-2: Bar diagram showing mean wet and dry granuloma weights (mg) - Cotton pellet induced granuloma model. 250 Ctrl Standard Test 200 Mean scores Wet Granuloma Dry Discussion Inflammation is a complex process involving various mediators, such as prostaglandins, leukotrienes and platelet activating factor. The major macrophage derived inflammatory mediators such as proinflammatory cytokines, tumour necrosis factor α and the reactive free radical nitric oxide contribute to the development of inflammatory diseases. The acute response is characterized by the rapid flooding of the injured tissue with fluid, coagulation factors, cytokines, chemokines, platelets and inflammatory cells (neutrophils in particular). Chronic inflammatory infiltrates are composed largely of lymphocytes, plasma cells and macrophages and often have an immune component. Acute and chronic IJPT July-2013 Vol. 5 Issue No Page 5616

8 inflammatory infiltrates often coexist. Tissue infection is a prototype of inflammatory response. Anti-inflammatory drugs inhibit different stages of inflammation. In Indian system of medicine, certain herbs are claimed to provide relief of pain and inflammation. The claimed therapeutic reputation has to be verified in a scientific manner. In the present study one such drug Aloe vera was taken for this study. In previous studies Aloe vera was found to have antioxidant 13, wound healing 14 and antimicrobial 15 properties. In a previous study Aloe vera leafy exudate of 25mg/kg was evaluated for its anti-inflammatory effect 112 and hence here an attempt was done to evaluate anti-inflammatory effect of Aloe vera using a different extract that is Aloe vera aqueous extract of dosage 25mg/kg. The acute experimental inflammatory models studied includes, Carrageenan rat paw edema and Formalin induced peritonitis. The chronic inflammatory model includes Cotton pellet induced granuloma model. In all the experimental inflammatory models, Indomethacin was used as Standard drug and aqueous extract of Aloe vera was used as test drug. The carrageenan-induced paw edema model in rats is known to be sensitive to cyclooxygenase inhibitors and has been used to evaluate the effect of non-steroidal anti-inflammatory agents, which primarily inhibit the cyclooxygenase involved in prostaglandin synthesis. 16 Inflammation induced by carrageenan involves three distinct phases of the release of the mediator, including serotonin and histamine in the first phase (0-2 h), kinins in the second phase (3 h), and prostaglandin in the third phase (>4 h) 17. In our study the aqueous extract of Aloe vera 25 mg/kg, p.o. significantly reduced edema induced by the carrageenan in both 2 nd and 3 rd phase. The PI of paw edema at 3 rd hour by Indomethacin was % while that of Aloe vera was %. The PI of paw edema at 4 th hour by Indomethacin was % while that of Aloe vera was %.Hence, Aloe vera showed 76.99% and % anti-inflammatory activity as that of standard Indomethacin at 3 rd and 4 th hour respectively under the present experimental conditions. Cotton pellet granuloma method is widely used to evaluate the transudative and proliferative components of the chronic inflammation. The moist weight of the cotton pellet correlates with the transudate, the dry weight of the pellet correlates with the amount of the granulomatous tissue 1. Cotton pellet granuloma provoked by the subcutaneous implantation of compressed cotton pellets. After few days histologically giant cells and undifferentiated connective tissue can be observed along with fluid infiltration. The amount of newly formed connective tissue can be measured after removal and weighing the dried pellets 8. The method has been useful for evaluation of steroidal and nonsteroidal IJPT July-2013 Vol. 5 Issue No Page 5617

9 anti-inflammatory drugs. For testing corticosteroids, the test can be performed in adrenalectomized rats. On the other hand, Aloe vera effect on dry weight of the cotton pellet was almost near that of the indomethacin. The percent inhibition of moist weight of cotton pellet formation by indomethacin was % and that of Aloe vera was %. Hence administration of Aloe vera and indomethacin appears to be effective in inhibiting the moist weight of cotton pellet under the present experimental conditions. The percent inhibition of granuloma formation by indomethacin was % and that of Aloe vera was %. Hence Aloe vera showed % anti-granuloma activity as that of standard indomethacin under the present experimental conditions. Aloe vera showed mild antiinflammatory activity in reducing granuloma formation as compared to the reference drug. In the present study Aloe vera showed significant results in the Carrageenan induced paw edema. The probable mechanism for the acute anti-inflammatory action could be due to anti-bradykinin activity and inhibition of synthesis of prostaglandins and other inflammatory mediators like histamine and serotonin in early hours of inflammation. The chronic anti-inflammatory activity could be due to the inhibition of fibroblast proliferation, synthesis of collagen and mucopolysaccrides during the granuloma formation. In a previous study, Aloe vera leafy exudate showed anti-inflammatory effect in both carrageenan and dextran induced inflammation in rats which was mediated via reduction of nitric oxide production in macrophages. 18 In another study, the Aloe vera gel extract showed antioxidant activity and possible mechanism of protective actions had been attributed to antioxidant activity as indicated by protection against increased lipid peroxidation. 19 Oxidative stress is the main pathology even in inflammatory disorders like Rheumatoid arthritis. 20 By nullifying stress due to antioxidant property, it may have a role in treating the inflammatory disorders. In another study, the Aloe vera peel extract showed antimicrobial activity 21, the additional property of antimicrobial along with anti-inflammatory activity of Aloe vera may have synergistic effects on the inflammation induced by the invading pathogens in inflammatory diseases. Further studies with higher dose or different solvent extracts or a long term administration of Aloe vera can throw more light on anti-inflammatory activity in chronic inflammatory models. Different assays based on other inflammation parameters like erythema, pain etc needs to be done. Standardization of the extracts, identification and isolation of active principles and pharmacological studies of these principles may be considered for further detailed studies. IJPT July-2013 Vol. 5 Issue No Page 5618

10 Conclusion Dr. Bhuvana* et al. International Journal Of Pharmacy & Technology At the end of the study it can be concluded that Aqueous extract of Aloe vera has shown anti-inflammatory effect in albino rats and the anti-inflammatory activity of Aloe vera is comparable to Indomethacin. However, Aloe vera also has antioxidant property, which may also be useful in various inflammatory disorders, as a secondary effect. It also has antimicrobial property. So anti-inflammatory, antioxidant and antimicrobial properties may act in synergy in the management of various inflammatory disorders. The anti-inflammatory property of Aloe vera may be due its ability to prevent the production of pro-inflammatory mediators like PG, histamine and serotonin, and may also be due to its antimicrobial, anti-oxidant effect. The present study envisaged that the use of Aloe vera either as monotherapy or along with the conventional medications may have an added benefit of anti-inflammatory activity in various inflammatory diseases. These studies are valuable for identifying lead compounds for anti-inflammatory drugs, keeping in mind the side effects of NSAIDs and corticosteroids. Since animal studies cannot be directly compared with effects on humans, further extensive studies need to be done to isolate the active substance/ substances responsible for its anti-inflammatory activity and confirm this activity in animal models as well as in clinical trials. Acknowledgement We acknowledge the encouragement and support of Dr B.M Parashivamurthy, Professor and H.O.D, Dept of Pharmacology, M.M.C.R.I, Mysore and we are also thankful to Himalaya Drug Company for providing the extract of Aloe vera. References 1. Carey WM, Dasi JM, Rao NV, Gottumukkala KM. Anti-inflammatory activity of methanolic extract of Bambusa vulgaris leaves. Int J Green Pharm 2009; 3: Derle DV, Gujar KN, Sagar B. Adverse effects associated with the use of nonsteroidal anti-inflammatory drugs: An overview. Indian J Pharm Sci 2006; 68: Al Mofleh IA, Al Rashed RS. Nonsteroidal, antiinflammatory drug-induced gastrointestinal injuries and related adverse reactions: Epidemiology, pathogenesis and management. Saudi J Gastroenterol 2007; 13: IJPT July-2013 Vol. 5 Issue No Page 5619

11 4. D. Mukherje, S.E. Nissen and E.J. Topol. Risk of cardiovascular events associated with selective COX-inhibitors. JAMA 2000; 286: Patel BG, Patel NB, Galani VJ. Argyreia speciosa (Linn. f.) sweet: A comprehensive review. Phcog Rev 2010;4: Bensky D, Gamble A, Kaptchuk TJ. Chinese herbal medicine: material medica. Seattle, Wash.: Eastland Press, 1993: xxv, Ghazanfar SA. Handbook of Arabian medicinal plants. Boca Rato: CRC Press, Ejoba Raphael, Phytochemical constituents of some leaves extract of Aloe Vera and Azadirachta indica plant species. Global Advanced Research Journal of Environmental Science and Toxicology 2012; 1(2) : Vogel HG. Analgesic, anti-inflammatory and antipyretic activity in Drug discovery and evaluation pharmacological assays, 2nd ed. New York: Springer; p Winter CA, Risley EA, Nuss GW. Carrageenan-induced edema in hind paw of rat as an assay for antiinflammatory drugs. Proc Soc Expt Biol Med 1962;111: Meier R, Schuler W and DeSaulles P. Zur Frage desmechanismus des hemming des Bindrgewehswachstums durch corticone. Experimentia 1950;6: R.Sambathkumar, T Sivakumar, R Shanmuga sundaram, P. Sivakumar, R. Nethaji, M. Vijayabasker, P. Perumal, M. Gupta, U.K. Mazumdar. Anti-inflammatory and analgesic effects of careya arborea stem bark in experimental animal models. Nig. J. Nat. Prod. and Med.Vol K R Anilakumar, K R Sudarshanakrishna, G Chandramohan, N Ilaiyaraja, Farhath Khanum & A S Bawa. Effect of aloe vera gel extract on antioxidant enzymes and azoxymethane-induced oxidative stress in rats. Indian journal of Experimental Biology 2010;48: Gupta N, Jain UK. Prominent wound healing properties of indigenous medicines. J Nat Pharm 2010;1: Ka Hee Kwon1, Min Ki Hong, Sun Young Hwang, Bo Youn Moon1, Sook Shin1, Jin Hong Baek2 and Yong Ho Park. Antimicrobial and immunomodulatory effects of Aloe vera peel extract. Journal of Medicinal Plants Research 2011; 5: IJPT July-2013 Vol. 5 Issue No Page 5620

12 16. Seibert K, Zhang Y, Leahy K and et al. Pharmacological and biochemical demonstration of the role of cyclooxygenase 2 in inflammation and pain. Proc Natl Acad Sci 1994; 91: Singh S, Majumdar DK, Rehan HMS. Evaluation of anti-inflammatory potential of fixed oil of Ocimum sanctum (Holybasil) and its possible mechanism of action. J Ethnopharmacol 1996;54: Sarkar D, Dutta A, Das M, Sarkar K, Mandal C, Chatterjee M. Effect of Aloe vera on nitric oxide production by macrophages during inflammation. Indian J Pharmacol 2005;31: K R Anilakumar, K R Sudarshanakrishna, G Chandramohan, N Ilaiyaraja, Farhath Khanum & A S Bawa. Effect of aloe vera gel extract on antioxidant enzymes and azoxymethane-induced oxidative stress in rats. Indian journal of Experimental Biology 2010;48: Sharma HL and Sharma KK. Haematopoietic Agents, Vitamins and Antioxidants, Chapter 52. Principles of pharmacology, 1 st edition. Paras publishers 2007: Ka Hee Kwon1, Min Ki Hong, Sun Young Hwang, Bo Youn Moon1, Sook Shin1, Jin Hong Baek2 and Yong Ho Park. Antimicrobial and immunomodulatory effects of Aloe vera peel extract. Journal of Medicinal Plants Research 2011; 5: Corresponding Author: Dr. Bhuvana K.B.M.B.B.S., M.D*, bhuvana.bvn@gmail.com IJPT July-2013 Vol. 5 Issue No Page 5621