Inflammopharmacology

The 'oil' abstained from Emu fat can be a very effective inhibitor of chronic inflammation in rats when appied dermally (which a skin penetration enhancer). Assays for this activity using the adjuvant-induced arthirtis model have shown:
1. Considerable variability in potency of some commercial oil samples.
2. Little or no correlation of activity with colour or linolenic acid (18.3) content of the Oil;
3. Relative stability of some active oils (to heal, aging at room temperature)'
4. The bulk of the anti-inflammatory activity was present in a low triglycferide fraction: and
5. Potential arthritis-suppressant/immunoregulant activity of these active fractions.

        These studies point to the need for more rigid quality control before considering such a (now proven) traditional medicine as a complementary therapy.
        Repeated applications of selections of selected oils did not induce any of the more prominent side effects associated with NSAIDs (e.g. platelet inhibition, gastrotoxicity) or certain anti-arthritic drugs (Proteinuria, leukopenia)

INTRODUCTION

        The Emu ('bush chook'), Dormaius (novae-hollandiae) is a free roving, large, flightless bird indigenous to Australia now farmed in Australia, Canada, Europe and the USA. The native Aboriginal and early white settlers in Australia rubbed on the liquid fat to facilitate wound fealing and to alleviate pain and disability from musculoskeletal disorders.
        An adult bird (15 months old) weighing 45 kg carries up to 10 kg of body fat, from which 7-8L of a thick oilis obtained by rendering at temperatures up to 150 degrees C. Filtering this semi-solid fat at 25 degrees C yields 20 80% (v/v) of clear oil (CO); the proportion varying with conditions of nurture and other factors (genetic stock, stress, etc.)

EXPERIMENTAL

        Unless indicated otherwise, Emu Fat samples were mixtures of both internal and external fat. These fat samples, free of blood and extraneous matter, were freshly minced at the time of slaughter, packed on ice (if not rendered immediately) and then rendered at controlled temperatures ranging from 30 degrees C to 95 degrees C. The semi-liquid fat/oil thus obtained showed considerable variations in clarity, viscosity and color (yellow). For routine testing, these oils and commerical samples were filtered at 25 C to remove solids and then diluted with sterile cold-pressed olive oil if necessary (e.g. for dose-response studies).
        After admixture with 15% (v/v) cineole Seucalyptol), samples were applied dermally (2.5ml kg - 1 day-1) for at least 4 days to shaved dorsum (6 cm2) of female outbred Wistar rats (160-200g) developing adjuvant-induced polyarthritis as previously described [1,2]. This protocol measures a therapeutic action, the animals having a previously established disease, with the first dose being given at the time of onset of arthritis. Signs of arthritis were measured before closing (day 10 post-adjuvant), after dosing (day 140 and again after a rebound/washout period 9 day 17). The latter observation served to eliminate those rats which were non-responders (n<15%) to the inoculated arthritigen given on day O.
        A blinded independent observer assessed the overall arthritic severity on day 14; giving each animal acore (0 to 5+) based on paw and tail inflammation and general condition of the animal. Changes in rear paw and maximal tail thickness were measured with a micrometer and forepaw inflammation was assessed arbitrarily (on a scale of 0 to 4+). Data are presented as means from five or more rats per experimental group.
        A second assay was based on treating female Dark Agouti (DA) rats (150.180g) with test fractions/oil co-administered in the arthritegenic adjuvant, ie.e. treatment was prophylactic with a single dose at the time triggering the arthritis. Wistar rats came from the University of Queensland Animal Farm; DA from the Animal Resources Centre at Murdock University (Western Australia).
        Oils proved active in the above assays were further treated by various fractionation procedures, not detailed here, to obtain (a) low-triglyceride-active concentrate which were 6% original oil volume, and (b) triglyceride-rich oil residues (>94% (v/v)).

RESULTS

Anti-inflammatory activity of various oils

Tables 1 and 2 expand on data previously [1] showing that Emu oils can differ greatly in their ability to suppress the expression of an ongoing experimental arthritis in rats when given transdemally in a therapeutic regime. Table 1 compared the activity of several oil samples carrying claims for potential therapeutic activity, assessed as soon as possible after they were purchased from commercial outlets. Some of these oils might have been subjected to vigorous processing (e.g. bleaching) to attain cosmetic grade. Since these data were generated in several experiments over a 24-month period, it is not feasible to record here full details of all measurements on the untreated controls. Likewise, Table 2 gives the relative activities of some freshly prepared oils derived from the internal/intestinal fat and the external/rump fat of the bird; these being feral (i.e. source from the wild, farmed intensively and dependent wholly on feed rations, or farmed with free access to considerable natural fodder. Although no simple correlation was evident between oil actively and food supply, the intestinal fat seems to carry more activity than the rump fat in each instance.

        Table 3 shows that the therapeutic activity was reasonably thermostable in some preliminary experiements on hearing selected oils. These were first obtained by rendering at 30C before being divided into two lots for comparison: one lot was then heated to 85C for 3 hours and the other maintained at 25C.
        In other experiements not detailed here, it was found that the colour of the oil (very marked in some, but not all, feral Emu fat samples) did not correlate with its anti-inflammatory activity, as disclosed in this bioassay. Some coloured oils showed marked deteration in potency on being exposed to sunlight, suggesting that the yellow pigment(s) might have photosensitizing activity and may accelerate the deterioration of the active principles.
        Table 4 compares an Emu Oil with other oils claimed to have therapeutic value for inflammatory disorders, when applied dermally with 15% cineole . These results indicate that Emu fat is a relatively unique source for transdermal anti-inflammatory activity. Oils rich in x- or y- linoenates, e.g. flax/linseed, evening primose, showed some modest activity. By contrast, no correlation was found between linolenate content of Emu Oils (ranging from .02 to 19.7%) and overall anti-inflammatory activity (data not shown).
        Table 5 shows that it is possible to segregate the bulk of the anti-inflammatory activity into low volume fractions. The oils used in this experiment were from birds farmed by Aboriginies at two widely separated locations (2500 km apart), bred from wild EMU's captured in their respective neighborhoods.
        Table 6 shows that by either (a) co-injecting the active fraction with an arthritigenic olive oil-based adjuvant or (b) injecting an alternative adjuvant constructed with test oils in lieu of olive oil), it was possible to see quite marked differences in the severity of the ensuing arthritis. This suggests that the oils contain a component that down regulates the initial response to the mycobacterial arthritigen by the immunoreactive cells in the draining lymph nodes.

Preliminary observations regarding safety

Arthritic animals at Atopsy after 10 dermal applications (2.5 ml kg - 1 day), no macroscopic abnormalities were noted post-mortem examinations (r = 30 rats). Platelet aggregation, in response to ADP or arachidonic acid ex vivo, was normal. Large doses of a 'good' oil (1ml/rat) administered orally caused no gastric irritation. By contrast, doses as low as 150 mg/kg of these good oils (suspecded in 0.04% Tween - 20) actually reduced the gastric irritation and bleeding caused by 50 mg/kg ibuprofen and 25 mg/kg naproxen PO in disease - stressed rats. We found no evidence for increased proteinuria (behond that seen in approximately 30% of the untreated arthritic animals) aster 10 days treatment with active oil.
The areas of skin exposed to emu oil (with or without admixed cincole) showed very little/no irritation, in contrast to that seen after applying some other transdermally active drugs notably certain 'topica' NSAIDs, E.G. piroxicam, copper salicylate, etc.

DISCUSSION

        This progress report further confirms the likely validity of repeated claims and testimony available in writing since 1820, that Aboriginal lore has located a naural medicine, transdermally active, for casing inflammatory signs and sysmptoms of musculoskeletal disorders. This testimony, both historic and contemporary, also indicates a likely analgesic action: the data presented here neither affirm or deny this analgesic property.
        Quite remarkably, from certain good/active oils was possible to obtain crude fractions with an activity superior to that of naproxen (w/w). These fractions stil contain some residual triglycerides and other diluents of the active compenent(s). These active fractions largely suppressed arthritic drugs, e.g. cyclosporin A [3,4] or zinc monoglyccrolate [2] and few rather unconventional NSAID's, e.g. lobenzarit [4], tenidap and nimcsulide.
        Like many alternative medicines, the credibility of emu oil has suffered from overstated claims for poorly characterized products that my sometimes even be adulterated (e.g. with chicken fat or linseed oil) without recognition of this fact. It is of prime importance to assert continuous quality control throughout the whole supply line, i.e. from selecting the best birds for (good/active) oil production, their feed and nurture through to the rendering of the crude fat and subsequent preservation of the extracted oil.
        This is yet another example of conditional pharmacology, often overlooked when we take for granted the consistency and potency of synthetic drugs. It should be recognized and more carefully defined in the context of using natural-sources remedies.
        One great advantage of emu oils is that they require little refining, unlike most animal fats. They also come from a renewable and Eco-sustainable resource, in contrast to so many petroleum-derived pharmaceuticals.

REFERENCES

Snowden JM. Whitehouse MW, anti-inflammatory action of emu oils. Inflammopharmacology, 1997;5 (2): 127-32
Whitehouse MW, Rainsford KD, Taylor RM, Vernon-Roberts B. and Zinc monoglyccrolate: a slow release source of zinc with anti-arthritic activity in rats, Agents Actions. 1990; 31:47-58
Rofe AM, Whitehouse MW, Bourgeois CS, Hayes Dr. Vernn-Roberts B. Prevention of adjuvant induced cachexia in rats by cvyclosporine - A Immunol Cell Biol. 1990; 68: 63-9
Haynes DR. Gadd SJ, Whitehouse MW, Mayrhofer G. Vernon-Roberts B. Complete prevention of the clinical expression of adjuvant - induced arthritis in rats by cyclosporine - A and lobenzafit, Inflame Res. 1996; 45:159-65