Intoxicação por Trema micrantha (Ulmaceae) em caprinos no Estado de Santa Catarina

The putative cannabinoid-secreting trichome of Trema micrantha (L.) Blume (Cannabaceae)

Trema, a genus of the popularly known Cannabaceae, has recently been the subject of cannabinoid bioprospection. T. micrantha is a tree with pharmacological potential widely used in folk medicine. It has two types of glandular trichomes, bulbous and filiform, spread throughout the plant body. Considering the proximity of this species to Cannabis sativa and Trema orientalis, species containing cannabinoids, the glandular trichomes of T. micrantha are also expected to be related to the secretion of these compounds. Thus, this study aims to detail the morphology of secretory trichomes during the synthesis, storing and release of metabolites in T. micrantha. We tested the proposition that they could be a putative type of cannabinoid-secreting gland. Pistillate and staminate flowers and leaves were collected and processed for ontogenic, histochemical, and ultrastructural analyses. Both types of glandular trichomes originate from a protodermal cell. They are putative cannabinoid-secreting sites because: (1) terpene-phenols and, more specifically, cannabinoids were detected in situ; (2) their secretory subcellular apparatus is consistent with that found in C. sativa: modified plastids, polyribosomes, an extensive rough endoplasmic reticulum, and a moniliform smooth endoplasmic reticulum. Plastids and smooth endoplasmic reticulum are involved in the synthesis of terpenes, while the rough endoplasmic reticulum acts in the phenolic synthesis. These substances cross the plasma membrane by exocytosis and are released outside the trichome through cuticle pores. The study of the cell biology of the putative cannabinoid glands can promote the advancement of prospecting for natural products in plants.

Poisoning in ruminants caused by species of the genus Cestrum L. (Solanaceae) in Brazil: A review of toxicological and phytochemical evidence

Some plant species of the genus Cestrum L. (Solanaceae family) are known to cause poisoning in farming animals in Brazil, negatively affecting the livestock sector. In this context, this study aimed to carry out a systematic review of the Cestrum species that cause poisoning in ruminants in Brazil and to list the main phytochemicals involved in these toxic activities that have already been identified. Scientific documents were retrieved in Google Scholar, PubMed®, ScienceDirect®, and SciELO databases. After applying the inclusion criteria, a total of 38 articles published between 1920 and 2023 were included in the present study. Cestrum axillare Vell. [Syn. Cestrum laevigatum Schltdl.], Cestrum corymbosum Schltdl., Cestrum intermedium Sendtn., and Cestrum parqui L'Hér. were found to have reported cases of poisoning in the Northeast, Southeast, and South of Brazil. Natural poisonings in ruminants caused by these species have been recorded in ten Brazilian states, mostly in Rio de Janeiro, Santa Catarina, Rio Grande do Sul, and Pernambuco. In general, Cestrum species cause liver damage and a clinical-pathological state characterized by acute liver failure of the poisoned animals. Cattle are more susceptible to poisoning by these plants, but there are reports of poisoning by C. axillare in goats and buffaloes as well. Several chemical constituents were identified in C. axillare and C. parqui, including some saponins and terpenoids that may be associated with the cases of poisoning. However, only one chemical compound has been identified in C. intermedium, and no phytochemical investigation has been carried out regarding toxic compounds in C. corymbosum. It is expected that future studies fill the gap in determining the toxic principles present in these species.

Neurotoxicosis in horses associated with consumption of Trema micrantha

BACKGROUND

Trema micrantha is a tree widely distributed throughout the Americas. The tree produces highly palatable leaves that have been associated with natural poisoning in goats, sheep and horses, in which hepatic necrosis and hepatic encephalopathy have been observed.

OBJECTIVES

This study describes malacia and haemorrhage in the central nervous system (CNS) due to T. micrantha consumption, with minimal to absent hepatic lesions.

STUDY DESIGN

Retrospective case series.

METHODS

A total of 14 horses with a history of neurological signs and spontaneous consumption of T. micrantha leaves were submitted to necropsy and multiple samples were collected for histopathology. Details of clinical history and signs of the horses were obtained through inquiries to the owners and attending veterinarians.

RESULTS

All the 14 horses had neurological signs of ataxia, severe sialorrhoea, involuntary running movements, sternal and lateral recumbency, and death after a clinical course that lasted from 24 h to 9 days. For a few days prior to onset of clinical signs, all horses had spontaneously consumed, potentially toxic doses of T. micrantha leaves. All 14 brains had diffuse yellowish discoloration affecting the rhombencephalon, mesencephalon, diencephalon, telencephalon and corpus striatum. In all cases, the most severe lesions were observed in the pons. Spinal cord lesions were observed affecting the lumbar intumescence, which was swollen with darken and depressed areas at the dorsal and ventral horns, and at the sacral level, which on cut surface displayed a friable and yellowish grey matter. The lesions observed grossly in brain and spinal cord consisted microscopically of severe vasculitis and liquefactive necrosis of white and grey matter of the brainstem, cerebellum and spinal cord.

MAIN LIMITATIONS

This is a small retrospective series relying on clinical observations reported by owners and attending veterinarians. The mechanism of action of the plant toxin in the CNS is still unidentified.

CONCLUSION

T. micrantha poisoning in horses causes predominantly a neurological disease, with minimal to absent hepatic lesions.

Novos aspectos sobre a intoxicação por Trema micrantha (Cannabaceae) em equídeos

Trema micrantha é uma planta arbórea distribuída amplamente no Brasil. Descrevem-se nesse trabalho novos aspectos epidemiológicos e patológicos relacionados com a intoxicação por essa planta em equídeos. Dois equinos adultos da raça Crioula e dois asininos, de localidades distintas, foram intoxicados naturalmente por Trema micrantha, após consumirem grande quantidade da planta que ficou disponível a eles após uma poda. Além disso, um cavalo adulto, de outra propriedade, que estava passando por restrição alimentar, se intoxicou após consumir as partes baixas de um grande número de árvores jovens de T. micrantha. Clinicamente, em todos os equídeos a doença se caracterizou por alterações neurológicas, que apareceram três a quatro dias após o consumo da planta, com curso clínico de dois a quatro dias (abreviadas por eutanásia). Os principais achados de necropsia foram observados no fígado, que estavam levemente aumentados e com padrão lobular evidente e no sistema nervoso central (SNC), com múltiplas áreas amareladas, focos de malacia e hemorragia, principalmente, no tronco cerebral e cerebelo. Histologicamente, havia necrose hepática aguda, edema acentuado no SNC com degeneração fibrinoide da parede de vasos associada a hemorragia e trombose e, frequentemente, com infiltrado de neutrófilos. Outras alterações observadas nos encéfalos foram: grande quantidade de astrócitos de Alzheimer tipo II na substância cinzenta, acúmulos de células Gitter e degeneração Walleriana próxima a focos de lesões vasculares.

Pneumotoxicosis in Sheep Caused by Ingestion of Trema Micrantha

Trema micrantha, a fast-growing tree distributed throughout the Americas, produces palatable leaves that have been associated with hepatic necrosis and acute death when consumed by livestock. This report describes fatal pulmonary disease of sheep triggered by consumption of Trema micrantha. Affected sheep had severe progressive dyspnea for a few days before death. Subcutaneous and mediastinal emphysema, reddened lungs, interalveolar septal thickening, and diffuse type II pneumocyte proliferation were the main pathological findings. After ingesting 77.5 and 102.5 g/kg (divided in 3 doses, at 30-day intervals) of T. micrantha leaves, 2 additional sheep developed the same condition. These findings indicate that T. micrantha toxicosis should be considered in the differential diagnosis of ovine respiratory disease.