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Poisoning by avocado (Persea americana) has been confirmed in sheep, goats, dogs, rabbits and ostriches. The clinical signs and lesions are attributed to the acetogenin, persin. Little is known regarding the epidemiology, clinical signs, lesions and therapy caused by acetogenin-induced heart damage. During the two-year study, we investigated a horse farm with six horses that often fed themselves with P. americana leaves or mature fruit pulp and skin on the ground. Two horses died, and one underwent necropsy, histopathology, and immunohistochemistry using the anti-cardiac troponin C (cTnC). Grossly and histopathologically, there was severe cardiac fibroplasia. Immunohistochemically, there was a multifocal decrease or negative expression in the cTnC cardiomyocytes' cytoplasm. Persea americana leaves were confirmed in the alimentary tract using botanical anatomy and molecular techniques. The chemical investigation by (LC-ESI-MS) revealed the presence of the acetogenins, persin and avocadene 1-acetate from P. americana. Persin was present in leaves and fruits (seed and pulp), while avocadene 1-acetate was found in leaves and fruits (seed, peel, and pulp) with a higher concentration in the pulp. Four other horses have been examined by electrocardiogram, echocardiogram and serum Troponin 1 (cTnI). To establish a causal effect of consumption of P. Americana and heart fibroplasia in horses, long-time experiments must be carried out.

Four experiments were conducted to measure the antioxidant activity of ethanol extracts of rosemary and oregano compared with synthetic antioxidants such as TBHQ and BHA/BHT. The antioxidant activity was determined and results differed from those of the Oven test at 63º C. Peroxide values and absorptivities at 232 nm of soybean oil under Oven test were lower in treatments with 25, 50, 75, 100 and 200 mg.Kg-1 TBHQ than in treatments with 1000 mg.Kg-1 oregano extract (O), 500 mg.Kg-1 rosemary extract (R) and their mixture R+O. All the treatments were effective in controlling the thermal oxidation of oils; the natural extracts were as effective as BHA+BHT and less effective than TBHQ. The natural extracts were mixed with 25, 50, 75 and 100 mg.Kg-1 TBHQ and then added to the oil. No improvement in antioxidative properties was observed. The best antioxidant concentration could be determined from polynomial regression and quadratic equation from the experimental data.Foram realizados quatro ensaios para verificação da atividade antioxidante de extratos etanólicos de alecrim (A) e orégano (O) comparados com os antioxidantes sintéticos TBHQ e BHA+BHT. Os resultados de atividade antioxidante do teste usando sistema modelo diferiram das respostas do teste acelerado em estufa. Nos ensaios em estufa os valores de peróxido e absortividade em 232nm dos óleos de soja, adicionados de 25, 50, 75, 100 e 200mg TBHQ. Kg-1, foram menores do que os dos óleos adicionados dos extratos de orégano (O) (1000mg.Kg-1), de alecrim (A) (500mg.Kg-1) ou da mistura deles (A + O). Todos os tratamentos retardaram a oxidação do óleo, entretanto os extratos naturais não atingiram a eficiência do TBHQ, mas foram tão efetivos quanto a mistura BHA+BHT. A adição dos extratos naturais a doses reduzidas de TBHQ não melhorou a eficiência em retardar a oxidação.

Four experiments were conducted to measure the antioxidant activity of ethanol extracts of rosemary and oregano compared with synthetic antioxidants such as TBHQ and BHA/BHT. The antioxidant activity was determined and results differed from those of the Oven test at 63o C. Peroxide values and absorptivities at 232 nm of soybean oil under Oven test were lower in treatments with 25, 50, 75, 100 and 200 mg.Kg-1 TBHQ than in treatments with 1000 mg.Kg-1 oregano extract (O), 500 mg.Kg-1 rosemary extract (R) and their mixture R+O. All the treatments were effective in controlling the thermal oxidation of oils; the natural extracts were as effective as BHA+BHT and less effective than TBHQ. The natural extracts were mixed with 25, 50, 75 and 100 mg.Kg-1 TBHQ and then added to the oil. No improvement in antioxidative properties was observed. The best antioxidant concentration could be determined from polynomial regression and quadratic equation from the experimental data.