Deadly toxin in Avacado pears

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Offline Andrew K Fletcher

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Deadly toxin in Avacado pears
« on: 28/04/2005 16:12:01 »

Avocados. The leaves, fruit, bark and seeds of avocados have
all been reported to be toxic. The toxic component in the avocado is "persin,"
which is a fatty acid derivative. Symptoms of toxicity include difficulty
breathing, abdominal enlargement, abnormal fluid accumulations in the chest,
abdomen and sac around the heart. The amount that needs to be ingested to cause
signs is unknown. Do not feed your pet any component of the avocado. lr= as_qdr=all q= persin+symptoms

Avocado (Persea americana) The toxic principle in avocado is persin and
leaves, fruit, bark, and seeds of the avocado have been reported to be toxic to
birds and various other species. Several varieties of avocado are available, but
not all varieties appear to be equally toxic. In birds, clinical effects seen
with avocado poisoning include respiratory distress, generalized congestion, and
death. Onset of clinical signs usually occurs after 12 hours of ingestion with
death occurring within 1-2 days of the time of exposure. Small birds such as
canaries and budgies are considered to be more susceptible, however, clinical
signs have been observed in other species.

HOLD THE GUACAMOLE, POR FAVOR! Thinking of giving Polly a little
something extra with her cracker? While there are a few foods that both humans
and pets can enjoy, there are others that, while perfectly palatable for people,
can be dangerous to our animal companions. The fruit of the avocado, for
example, poses a threat to a number of species. "Avocados contain a toxic
component called persin," explains Jill A. Richardson, DVM, of the ASPCA Animal
Poison Control Center (APCC), "which has been shown to produce cardiac tissue
damage, respiratory distress and mammary gland damage in a variety of
animals--including horses, goats, sheep, dogs, cattle, rabbits, fish and
birds." Consider the case of the cockatiel who had been given some
guacamole by his owner. Within four hours of ingestion, the bird started
behaving strangely--puffing his feathers and acting uncomfortable--and
got progressively worse. The bird's owner brought him to an emergency clinic,
and the veterinarian there contacted the APCC. Says Richardson, "We gave him
recommendations on treating the animal--an oxygen cage and diuretics to remove
the fluid on the bird's lungs." The animal was hospitalized for several days,
but recovered. "And needless to say," adds Richardson, "guacamole is NOT on the
menu any longer!" If you suspect that your animal companion has eaten
avocado--or any other potentially dangerous substance--call your veterinarian or
the APCC's emergency hotline at 1-888-4-ANI-HELP for round-the-clock telephone
assistance. For more information on poison prevention, visit

Nat Toxins. 1995;3(5):344-9.

Related Articles, Links

Isolation and identification of a compound from avocado
(Persea americana) leaves which causes necrosis of the acinar epithelium of the
lactating mammary gland and the myocardium. Oelrichs PB, Ng
JC, Seawright AA, Ward A, Schaffeler L, MacLeod JK. National Research
Centre for Environmental Toxicology, Coopers Plains, Brisbane,
Queensland. It is well known that when lactating livestock eat avocado
(Persea americana) leaves they may develop non-infectious mastitis and
agalactia. This is associated with extensive coagulation necrosis of the
secretory acinar epithelium and interstitial oedema, congestion, and
haemorrhage. Similar lesions have been produced in mammary glands of lactating
mice fed a diet containing a small percentage of freeze-dried avocado leaf.
Tests using these animals have been used to isolate the active principle, termed
"persin," from avocado leaves. The purified persin was examined using IR, NMR,
and UV spectroscopy and mass spectrometry, and identified as
(Z,Z)-1-(acetyloxy)-2-hydroxy-12,15-heneicosadien-4-one. Persin has previously
been isolated from avocado leaves and shown to have antifungal properties and to
be toxic to silkworms. Our tests have shown that persin at the dose rate of
60-100 mg/kg has the same effect on mammary glands in lactating mice as leaves
from avocado. Enantioselective syntheses of the R and the S isomers of persin
and related derivatives were carried out. These compounds were tested for
activity required to induce widespread lactating mammary gland necrosis in mice,
and only the R isomer was found active. At doses of persin above 100 mg/kg
necrosis of myocardial fibres may occur and hydrothorax may be present in
severely affected animals. The mechanism of action of persin on both the mammary
gland and the myocardium remain to be resolved.

Aust Vet J. 1989 Jul;66(7):206-11.

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Pathological changes in the mammary gland and biochemical
changes in milk of the goat following oral dosing with leaf of the avocado
(Persea americana). Craigmill AL, Seawright AA, Mattila T,
Frost AJ. Department of Veterinary Pathology and Public Health,
University of Queensland, St Lucia, Australia. Two varieties of avocado
leaves (Persea americana var Guatemalan and var Mexican) were administered to
lactating goats. The Mexican variety was without effect. The Guatemalan variety
in doses exceeding 20 g fresh leaf per kg bodyweight, produced damage to the
mammary gland with decreased milk production. The lesions were characterised by
oedema and reddening, with clots in the large ducts. Microscopically, there was
widespread degeneration and necrosis of the secretory epithelium, the necrotic
cells sloughing into the lumen. There was no significant cellular inflammatory
response. Concentrations of antitrypsin in the milk, indicating changes in
vascular permeability, increased rapidly 15 h after a single high dose,
coinciding with palpable oedema. Concentrations of NAGase, indicating cell
damage, increased after 24 h. Goats given multiple doses followed a similar
pattern but the initial response was delayed. The toxic principle, and its mode
of action in selectively damaging mammary secretory cells, remains to be

1: J S Afr Vet Assoc. 1991 Dec;62(4):186-8.

Related Articles, Links

Suspected avocado (Persea americana) poisoning in
goats. Stadler P, van Rensburg IB, Naude
TW. Department of Medicine, Faculty of Veterinary Science, University
of Pretoria, Onderstepoort, Republic of South Africa. A herd of 15
Cameroon goats was suspected of having been poisoned by eating leaves of the
Fuerte variety of avocado pear (Persea americana). Two of the affected goats
were examined clinically, while necropsies were carried out on 3 of the 4 that
had died. The most significant clinical findings were tachycardia, hyperpnoea
and evidence of lung oedema. At necropsy severe lung oedema, hydrothorax and
hydropericardium were present. Severe myocardial degeneration, necrosis and
fibrosis were the major histopathological findings. Publication Types:

Case Reports

: J S Afr Vet Assoc. 1991 Mar;62(1):21-2.

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Cardiomyopathy caused by avocado (Persea americana Mill)
leaves. Grant R, Basson PA, Booker HH, Hofherr JB,
Anthonissen M. Central Veterinary Laboratory, Windhoek,
Namibia. Six of 21 goats feeding on fresh avocado (Persea americana)
leaves from pruned trees, showed clinical signs of cardiac distress. Some sheep
subsequently dosed experimentally at different dosage rates with the same and
other avocado varieties, showed clinical signs of respiratory or cardiac
distress and myocardial lesions at autopsy. PMID: 2051443 [PubMed -
indexed for MEDLINE]

1: J S Afr Vet Assoc. 1994 Sep;65(3):113-8.

Related Articles, Links

Cardiomyopathy in ostriches (Struthio camelus) due to
avocado (Persea americana var. guatemalensis)
intoxication. Burger WP, Naude TW, Van Rensburg IB, Botha
CJ, Pienaar AC. Ostrich Research Centre, Oudtshoorn, Republic of
South Africa. Nine out of 120 ostriches died from congestive heart
failure within 96 h of ingesting avocado leaves and immature fruit in an avocado
orchard containing Hass and Fuerte cultivars. Foliage and immature fruit from
both cultivars dosed to ostriches (n = 4) and domestic hens (n = 8) resulted in
severe cardiomyopathy in all the ostriches. In the hens, which had received a
lower dose, milder lesions occurred. Macroscopically the intoxication in
ostriches resulted in a severe anasarca of the neck and ventral body. The
cardiomyopathy was characterised by degeneration and necrosis of myocytes, a
marked infiltration of heterophils and in one case, early
fibroplasia. PMID: 7595917 [PubMed - indexed for MEDLINE]

1: J Allergy Clin Immunol. 2003 Nov;112(5):1002-7.

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FPRIVATE "TYPE=PICT;ALT=Click here to read"
Analysis of avocado allergen (Prs a 1) IgE-binding
peptides generated by simulated gastric fluid
digestion. Diaz-Perales A, Blanco C, Sanchez-Monge R,
Varela J, Carrillo T, Salcedo G. Departamento de Biotecnologia,
E.T.S. Ingenieros Agronomos, UPM, Madrid, Spain. BACKGROUND: Resistance
to pepsin digestion has been claimed to be a characteristic of food allergens
that can induce severe adverse reactions. Moreover, pepsin treatment is included
in protocols to evaluate the potential allergenicity of transgenic foods.
Allergenic plant class I chitinases, such as avocado Prs a 1, are the
panallergens involved in the latex-fruit syndrome. Previous reports indicated
their susceptibility to simulated gastric fluid (SGF) digestion. OBJECTIVE: We
sought to evaluate the IgE-binding capacity and the in vivo reactivity of the
SGF products of the avocado allergen Prs a 1. METHODS: Patients with a clinical
history of latex-fruit allergy syndrome, a positive skin ***** test (SPT)
response to Prs a 1, and specific IgE to avocado were selected. Untreated and
SGF-digested Prs a 1 samples were analyzed by means of IgE and IgG
immunoblotting, IgE immunoblotting and ELISA-inhibition assays, and SPTs.
Peptides from SGF-digested samples were fractionated by means of HPLC,
characterized by N-terminal amino acid sequencing and matrix-assisted laser
desorption/ionization analysis, and tested for in vivo reactivity with SPTs.
RESULTS: Neither protein staining nor IgE immunoblotting with a pool of sera
from allergic patients resulted in the detection of any band after SDS-PAGE
separation of an SGF-digested sample of Prs a 1. However, this sample showed a
similar inhibitory potency to that of untreated Prs a 1 in both immunoblot- and
ELISA-inhibition assays (up to 70% inhibition of the IgE binding to crude
avocado extract) and induced positive SPT responses in 5 of 8 allergic patients.
Peptides from SGF-digested Prs a 1 were separated by means of HPLC, and 4 of
them reached more than 50% inhibition values when using avocado extract as the
solid phase in ELISA-inhibition assays. Reactive peptides were located both in
the N-terminal hevein-like domain and in the catalytic domain of Prs a 1. Those
corresponding to the hevein-like domain (approximately 5100 d) produced positive
SPT responses in 5 of 8 allergic patients, whereas 2 peptides located in the
catalytic domain (approximately 1400 and 2500 d) were reactive in 2 or 3 of the
8 patients. CONCLUSION: Prs a 1 was extensively degradated when subjected to SGF
digestion. However, the resulting peptides, particularly those corresponding to
the hevein-like domain, were clearly reactive both in vitro and in

Allergy. 1994 Jul;49(6):454-9.

Related Articles, Links

Avocado hypersensitivity. Blanco C,
Carrillo T, Castillo R, Quiralte J, Cuevas M. Department of Allergy,
Nuestra Sra. del Pino Hospital, Las Palmas de Gran Canaria, Canary Islands,
Spain. The avocado (Av) is a fruit that belongs to the Lauraceae family.
We report 17 patients with immediate hypersensitivity to avocado. Clinical
manifestations in relation to avocado ingestion were as follows: systemic
anaphylaxis in seven patients, angioedema/urticaria in six, vomiting in two,
bronchial asthma in one, and rhinoconjunctivitis in one. Skin ***** test (SPT)
with fresh avocado was positive in all patients with the Strong avocado variety
(SAv) and in 14 patients with the Hass avocado variety (HAv). Our
patient-associated sensitizations were as follows: 10 to latex, eight to
chestnut, eight to banana, four to kiwi, and four to walnut. Avocado-sensitized
patients with latex allergy were typically middle-aged women, professionally
exposed to latex, who also exhibited frequent associated sensitizations to
chestnut, banana, and other fruits. Specific IgE against avocado was
demonstrated in 11 of our patients, by both commercial CAP and RAST with avocado
extract coupled to nitrocellulose disks. Despite its lower protein content, SAv
seems to be more allergenic than HAv, both in vivo and in vitro. On incubating a
pool of sera from our patients with avocado, latex, chestnut, and banana
extracts, a progressive RAST inhibition was obtained, with SAv- and
chestnut-marked disks. This suggests the existence of common antigenic
determinants among these allergens.

Death is natures way of telling us to slow down.
« Last Edit: 01/05/2005 11:35:37 by Andrew K Fletcher »
Science is continually evolving. Nothing is set in stone. Question everything and everyone. Always consider vested interests as a reason for miss-direction. But most of all explore and find answers that you are comfortable with


Offline Andrew K Fletcher

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Re: Deadly toxin in Avacado pears
« Reply #1 on: 01/05/2005 11:37:29 »
I posted this, because I feel eating these fruits in large amounts, thinking it was a healthy source of vitamins, minerals and fats, has damaged my kidneys. It certainly is a possibility having read what it has done to other animals that consume them.


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Science is continually evolving. Nothing is set in stone. Question everything and everyone. Always consider vested interests as a reason for miss-direction. But most of all explore and find answers that you are comfortable with