Review on Emu Products for Use As Complementary and Alternative Medicine
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Nutrition 31 (2015) 21–27 Contents lists available at ScienceDirect Nutrition journal homepage: www.nutritionjrnl.com Review Review on emu products for use as complementary and alternative medicine Manish Kumar Jeengar M.S. (Pharm.) a, P. Sravan Kumar a, Dinesh Thummuri M.S. (Pharm.) a, Shweta Shrivastava M.S. (Pharm.) a, Lalita Guntuku M.S. (Pharm.) a, Ramakrishna Sistla Ph.D. b, V.G.M. Naidu Ph.D. a,* a Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education & Research (NIPER-Hyderabad), Balanagar, India b Pharmacology Division, Indian Institute of Chemical Technology, Hyderabad, India article info abstract Article history: Emu (Dromaius novaehallandiae), the flightless bird native to Australia and found in many Received 10 January 2014 countries, is receiving much attention for its nutritional benefits as well as its medicinal value. Emu Accepted 1 April 2014 oil contains high amounts of polyunsaturated fatty acids and antioxidants. It has potent anti- inflammatory actions and thus can be used topically and orally to treat conditions such as Keywords: mucositis, inflammatory bowel syndrome, and auricular inflammation, and to prevent Emu oil chemotherapy-induced bone loss. Emu oil also has a hypocholesterolemic effect, transdermal PUFAs penetration-enhancing activity, cosmetic and insect repellent activity, and so on. However, its MUFA Inflammation mechanism(s) of actions are unclear and have not, to our knowledge, been studied to date. Previous Antioxidant studies suggest that the fatty acids of the u-9, u-6, and u-3 series, which are present in emu oil, Penetration enhancer may act on cyclooxygenase, lipoxygenase, and lipoxin pathways to bring about its anti- GPR120 inflammatory and other beneficial actions. The aim of this review was to provide a brief sum- mary of the current knowledge of research on emu products, mainly emu oil, for the possible use as a complementary and alternative natural medicine for various chronic diseases. In this review we also highlighted the future research scope of emu oil for its possible antidiabetic activity. Thus, emu oil is an attractive pharmacologic agent to further explore for its therapeutic activity to treat various ailments. Ó 2015 Elsevier Inc. All rights reserved. Introduction attributed to its body fat content. Emus store their fat on their back, which is known as the back pad. Because of where the fat is Ratites are a diverse group of flightless birds belonging to the stored, emu meat is very lean and devoid of fat. Emus have both superorder Palaeognathae and order struthioniformes. They have nutritional value and health benefits [4]. flat breast bones with no keel, giving the wing muscles nothing to anchor to, and thus they are unable to fly. Emus belong to ratite group of flightless birds, along with ostrich, rhea, kiwi, Emu egg choique and cassowary [1]. The emu (“bush chook”), Dromaius novaehallandiae, is a free-roving, cursorial bird indigenous to The emu egg is dark green in color and weighs about 400 to Australia for 80 million years [2]. Native aboriginals and white 650 g. The color of the egg results from the presence of methyl settlers used the liquid fat from emus topically for various ail- ester in the pigment biliverdin in the egg shell. Emus lay one egg ments such as wound healing, to alleviate pain, and for muscu- every 3 or 5 d during breeding season, i.e., between April and ’ loskeletal disorders. Emu is the second-largest extant bird in the October. The egg s shell contains about 95% calcium carbonate in world by height. The only extant species is D. novaehallandiae the form of calcite, as well as two different C-type lectin-like [3,4]. An adult emu weighs about 45 kg, of which 10 kg can be proteins that are common among ratite group. Emu eggs contain 29% to 47% albumen. Chemically, albumen contains 0.05% of lysosome and 3.1% of sialic acid, whereas the egg white * Corresponding author. Tel.: þ91 944 051 7979; fax: þ91 40 23073751. of the domestic hen contains 3.4% lyosome and 0.29% sialic E-mail address: [email protected] (V. G. M. Naidu). acid [4]. 0899-9007/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.nut.2014.04.004 22 M. K. Jeengar et al. / Nutrition 31 (2015) 21–27 Emu meat Table 1 Composition (%) of fatty acids in emu oil Emus are a good source of nutrition, and its meat is very Fatty acid Amount (%) flavorful. Emu meat is lean, low in cholesterol, and has a favorable Palmitic (16:0) 24.0 fatty acid profile [5]. Lipids present in emu meat include both u-3 Palmitoleic acid (16:1; u-7) 4.3 and u-6 fatty acids such as a-linolenic, linoleic, arachidonic, and Stearic acid (18:0) 8.5 Oleic (18:1; u-9) 49.1 docosahexaenoic acids (DHAs), the levels of which are greater Linoleic (18:2; u-6) 9.5 than those present in chicken and beef [6,7]. The ratio of poly- a-Linolenic (18:3; u-3) 1.1 unsaturated fatty acids (PUFAs) to saturated fatty acids was found Saturated 32.5 to be 0.72, which is higher than chicken meat at 0.57 and beef at MUFA 53.4 0.3 [6]. Heme iron (cf. 3.4–5.0 mg iron/100 g) is present in abun- PUFA 10.6 dant amounts in emu meat compared with beef. Different mus- MUFA, monounsaturated fatty acid; PUFA, polyunsaturated fatty acid cles have different amounts of meat pigment (varying from 22 to 29 mg/g of tissue) and increases with the age of the animal from 6 include diarrhea, severe pain, nausea, and bloating [17].Thereare to 14 mo. The American Heart Association recommends con- currently several unmet needs for the prevention and treatment of sumption of emu meat because of its low fat content and because chemotherapy-induced gastrointestinal mucositis [18];however, it is a good source of proteins, vitamins, heme iron, and creatine. some agents such as keratinocyte growth factor-1 [19], insulin-like Emu meat also is a rich source of vitamins A and E. growth factor-1 [20], whey growth factor extract [21], and vela- In view of the presence of a significant amount of creatine, fermin (fibroblast growth factor-20) [22] are being investigated. emu meat is considered beneficial for athletes who indulge in Emu oil has been explored as a possible alternative therapy for high-endurance sports. The high concentration of creatine aug- chemotherapy-induced mucositis, and it has been reported that ments lean body mass, and also increases performance in various orally administered emu oil decreased acute inflammation and activities. Emu meat contains higher amounts of myoglobin altered selected small intestinal parameters in 5-fluorouracil (sarcoplasmic heme protein, important for both oxygen storage (5-FU)-induced mucositis in a rat model [23]. and oxygen delivery functions in skeletal muscles), which gives Inflammatory bowel disease the meat its dark color, similar to that of red meat [8]. Inflammatory bowel diseases such as ulcerative colitis and Emu oil Crohn’s disease are generally managed by immunosuppressive agents, antibiotics, corticosteroids, and 5-aminosalicylic acid Emu oil is obtained from the emu’s fat deposits, mainly subcu- [24]. In experimental animals, emu oil ameliorated dextran sul- taneous and retroperitoneal fat. Collected tissues are first subjected phate sodium-induced colitis in rats and decreased the severity to maceration or centrifugation and then liquified fat is passed of tissue damage to a significant degree. Emu oil enhanced through various filters to obtain pure oil [9]. Emu oil is a commer- colonic crypt lengthening, indicating its ability to stimulate in- cially available product in countries such as Australia and the testinal repair processes. Moreover, it has no effect on the su- United States. It possesses various beneficial characterisitics. It is an crose breath test, indicating that it maintains normal intestinal anti-inflammatory, it promotes enhancementof skinpermeation, it function [25]. Further studies are needed to evaluate the mech- is moisturizing and has cosmetic properties, and it has been used anism(s) of action of emu oil in ameliorating symptoms of in- for the treatment of various ailments for decades [4,10,11]. flammatory bowel disease. Composition of emu oil Auricular inflammation Emu oil is a bright yellow liquid [12]. It contains 98.8% and 98% of the average amount of lipids in oils obtained from subcutane- It has been reported that emu oil decreases auricular fl ous and retroperitoneal adipose tissues, respectively. The fatty in ammation in CD-1 mice. It was noted that emu oil reduced fi acid composition of emu oil depends on the diet of the bird, the auricular thickness and weight of ear plug, signi cantly, which method of extraction, and the type of adipose tissue from which was also accompanied by a 70% reduction in interleukin (IL)-1a the oil is extracted [9,13]. Emu oil is reported to contain all three and a 60% drop in tumor necrosis factor (TNF)-a compared to the omega fatty acids (i.e., u-9, u-6, and u-3), making it an excellent control group [26]. supplement. The largest component is oleic acid, a mono- unsaturated u-9 fatty acid (18:1), comprising >49.1% of the total Cancer chemotherapy-induced bone loss fatty acids. Emu oil also contains unsaturated fatty acids like 9.5% linoleic acid (18:2; u-6), 1.1% a-linolenic acid (18: u3), and 32.5% Cancer chemotherapy can cause osteoporosis or osteopenia. saturated fatty acids as previously reported [14] (Table 1). The 5-FU, methotrexate, cyclophosphamide, and etoposide induce non-triglyceride (TG) fractions include various compounds like osteopenia by reducing osteoblast activity and increasing oste- antioxidants, notably carotenoids, flavones, polyphenols, and oclast activity [27,28].