The toxicity of Senecio inaequidens DC.

Abstract

This study was designed to confirm the toxicity of a plant implicated in an outbreak of poisoning of stock in Frankfort, Free State Province, South Africa. Cows died acutely after being introduced into a camp, where an abundant, green shrublet was noted to be heavily grazed. This plant was subsequently identified as Senecio inaequidens DC. (Asteraceae) by the South African National Biodiversity Institute (SANBI). Extraction and chemical analyses for pyrrolizidine alkaloids (PAs) in Senecio inaequidens revealed the presence of 4 different compounds, namely retrorsine and senecionine (known to be hepatotoxic) and 2 unidentified compounds. The average total PA (free base plus N-oxide) concentration in plant parts of S. inaequidens collected at Frankfort during the outbreak was 0.81 %, compared with the total alkaloid content in the dried, milled S. inaequidens plant material, collected 7 weeks after the outbreak, of only 0.18 %. Male Sprague-Dawley rats (n=4), aged 8-9 weeks, were dosed per os. Each rat received a different dose of the crude Senecio inaequidens extract, ranging from 0.049 mg/g body weight (b.w.) to 0.25 mg/g b.w. No clinical signs were observed in the rat receiving the lowest dose. Rats receiving higher doses showed depression, an unsteady gait, pilo-erection and jaundice, which was particularly noticeable in the ears. Clinical chemistry evaluation revealed an increase in the activities of ALP (except Rat 4), AST and GGT in all animals. Total serum bilirubin, creatinine and urea concentrations were also elevated. All rats had low serum globulin concentrations with an A/G ratio above 1.2. Post mortem examination of the rats revealed marked hepatic lesions. Histopathologically, these changes were characterised by necrosis (variable in extent) of the centrilobular and midzonal hepatocytes (but sparing the portal hepatocytes), with extensive haemorrhage and congestion. Proliferation of the bile ducts, fibrosis and oedema were also present. Ultrastructural changes in affected rats were characterised by margination of chromatin, the presence of numerous autolysosomes in necrotic hepatocytes, intramitochondrial woolly inclusions and changes in the endoplasmic reticulum. A sheep, also dosed with the crude extract, failed to exhibit clinical signs, clinical chemistry aberrations or macroscopic lesions; however, examination of the liver of this sheep revealed histopathological and ultrastructural changes similar, though milder, to those displayed by the rats. Pyrrolizidine alkaloids were extracted from the liver and kidneys of the rats and the sheep. In the case of the sheep, retrorsine was also detected in the lungs, urine and bile

Seasonal variability in pyrrolizidine alkaloids inSenecio inaequidensfrom the Val Venosta (Northern Italy)

“…This has also been observed in Cynoglossum officinale from the Boraginaceae plant family containing PAs where the highest alkaloid contents were in the inflorescences and young rosette leaves (Van Dam et al 1995). Similarly, the highest alkaloid contents were found in the inflorescences of various Senecio species (Chizzola et al 2010, Dimande et al 2007, Hartmann and Zimmer 1986). In the same way young Colchicum autumnale leaves contained more colchicine than later in the growing season (Winter et al 2013).…”

“…The identified alkaloids were already reported in literature. Retrorsine and senecionine were the main alkaloids in South African plants (Dimande et al 2007). Similarly, Wiedenfeld et al (1981) found 0.21 % retrorsine and 0.064% senecionine in S. inaequidens.…”

Distinguishing between toxic and non-toxic pyrrolizidine alkaloids and quantification by liquid chromatography–mass spectrometry

“…The high concentration (12000 µg/g) of unsaturated PAs detected in the plant implicated this Senecio species as the cause of toxicity and the presence of the toxic PAs in the rumen content confirmed exposure of the cows. The diagnosis of PA poisoning was corroborated by histopathological evidence of diffuse centrilobular to submassive necrosis and haemorrhage in liver samples collected from the dead cows (Dimande et al, 2007).…”

“…Crotalaria sphaerocarpa seeds were collected from a maize farm 2 km north of Oberholzer in (Dimande et al, 2007). Necropsies were performed on cattle that have died and rumen content (500 g) was collected and submitted for analysis together with the collected plant material.…”

Alien taxa of the tribe Senecioneae (Asteraceae) in Italy: a nomenclatural synopsis

“…Giunti et al 2015)]. This species causes ecological, economical and social impacts: loss of biodiversity (especially in meadows and pastures, see Giunti et al 2015), reduction in productivity and quality of cultivated lands (especially wineyards, see Banfi & Galasso 2010: 248), and threats to the health of humans and domesticated animals (cows, horses, and sheeps) on account of its a high concentration of toxic pyrrolizidine alkaloids, which are passed also through milk and honey (see e.g., Dimande et al 2007). Giunti et al (2015) Photos: Danin (2015).…”