ReviewReview on emu products for use as complementary and alternative medicine
Introduction
Ratites are a diverse group of flightless birds belonging to the superorder Palaeognathae and order struthioniformes. They have 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, choique and cassowary [1]. The emu (“bush chook”), Dromaius novaehallandiae, is a free-roving, cursorial bird indigenous to Australia for 80 million years [2]. Native aboriginals and white settlers used the liquid fat from emus topically for various ailments such as wound healing, to alleviate pain, and for musculoskeletal disorders. Emu is the second-largest extant bird in the world by height. The only extant species is D. novaehallandiae [3], [4]. An adult emu weighs about 45 kg, of which 10 kg can be 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 stored, emu meat is very lean and devoid of fat. Emus have both nutritional value and health benefits [4].
Section snippets
Emu egg
The emu egg is dark green in color and weighs about 400 to 650 g. The color of the egg results from the presence of methyl ester in the pigment biliverdin in the egg shell. Emus lay one egg every 3 or 5 d during breeding season, i.e., between April and October. The egg's shell contains about 95% calcium carbonate in the form of calcite, as well as two different C-type lectin-like proteins that are common among ratite group. Emu eggs contain 29% to 47% albumen. Chemically, albumen contains 0.05%
Emu meat
Emus are a good source of nutrition, and its meat is very flavorful. Emu meat is lean, low in cholesterol, and has a favorable fatty acid profile [5]. Lipids present in emu meat include both ω-3 and ω-6 fatty acids such as α-linolenic, linoleic, arachidonic, and docosahexaenoic acids (DHAs), the levels of which are greater than those present in chicken and beef [6], [7]. The ratio of polyunsaturated fatty acids (PUFAs) to saturated fatty acids was found to be 0.72, which is higher than chicken
Emu oil
Emu oil is obtained from the emu's fat deposits, mainly subcutaneous and retroperitoneal fat. Collected tissues are first subjected to maceration or centrifugation and then liquified fat is passed through various filters to obtain pure oil [9]. Emu oil is a commercially available product in countries such as Australia and the United States. It possesses various beneficial characterisitics. It is an anti-inflammatory, it promotes enhancement of skin permeation, it is moisturizing and has
Mucositis
Mucositis is the most common adverse effect of cancer chemotherapy and is characterized by the depletion of the mucous layer in the alimentary tract [16]. Symptoms associated with mucositis include diarrhea, severe pain, nausea, and bloating [17]. There are currently several unmet needs for the prevention and treatment of chemotherapy-induced gastrointestinal mucositis [18]; however, some agents such as keratinocyte growth factor-1 [19], insulin-like growth factor-1 [20], whey growth factor
Hypocholesterolemic effect
Emu oil possesses hypocholesterolemic activity. A comparative study between emu oil and olive oil concluded that hamsters fed a refined emu oil diet had significantly reduced serum total cholesterol (TC) and low-density lipoprotein (LDL) levels, with no effect on plasma high-density lipoprotein (HDL) and TG levels compared with animals on the olive oil diet. Furthermore, emu oil reduced the ratio of TC to HDL to a significant degree. Hamsters fed a refined emu oil diet showed significantly
Possible mechanism(s) of actions
To our knowledge, no scientific study has been reported for the potential mechanism(s) of action of the therapeutic effects of emu oil. In general, saturated fatty acids are proinflammatory, unsaturated fatty acids are weakly proinflammatory or neutral, and ω-3 fatty acids are anti-inflammatory [43]. It also has been reported that γ-linolenic acid (GLA), an essential ω-6 fatty acid, also contains anti-inflammatory activity [44]. The anti-diabetic and anti-inflammatory properties of oleic acid
Emu oil and diabetes
To our knowledge, there are currently no scientific results available on the effect of emu oil on diabetic conditions; however, the anti-diabetic effect of the fatty acids that are present in the composition of emu oil has been reported previously. Oleic acid was found to reverse the inhibitory effect on insulin production caused by the inflammatory cytokine (TNF-α) in both in vitro and in vivo systems [45]. GLA has proven useful in insulin resistance [44] and in the prevention and treatment of
Conclusions
In this review, we highlighted the importance of emu products, mostly emu oil, as possible use in complementary and alternative medicine. We demonstrated that the main therapeutic effect shown by emu oil is its anti-inflammatory potential, for which it can be used in alternative medicine, and its penetration-enhancing property may be useful as a complement to conventional medicines.
We also have demonstrated that the beneficial effect of emu oil appears to be mediated by its unsaturated fatty
Acknowledgments
The authors acknowledge the Department of Pharmaceuticals, Ministry of Chemicals and Fertilizers, government of India for financial support to MKJ, TD, SS, LG, and PSK.
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