Toxicity of Nerium oleander in the monkey (Cebus apella)

Toxicological assessment compilation of selected examples of raw materials for homeopathic and anthroposophic medicinal products - Part 2

The present successor article comprises more than 180 substances representing a continuative compilation of toxicologically evaluated starting materials prompted by the wide use and high number of homeopathic and anthroposophic medicinal products (HMP) on the market together with the broad spectrum of active substances of botanical, mineral, chemical or animal origin contained therein, and by the equally important requirement of applying adequate safety principles as with conventional human medicinal products in line with the European regulatory framework. The February 2019 issue of the Regulatory Toxicology and Pharmacology journal includes the antecedent article bearing the same title and entailing safety evaluations of more than 170 raw materials processed in HMP. This part 2 article highlights scientific evaluation following recognized methods used in toxicology with a view to drug-regulatory authority's assessment principles and practice in the context of HMP, and offers useful systematic, scientifically substantiated and simultaneously pragmatic approaches in differentiated HMP risk assessment. As a unique feature, both articles provide the most extensive publicly available systematic compilation of a considerable number of substances processed in HMP as a transparent resource for applicants, pharmaceutical manufacturers, the scientific community and healthcare authorities to actively support regulatory decision making in practice.

Inflammasome inhibition blocks cardiac glycoside cell toxicity

Chronic heart failure and cardiac arrhythmias have high morbidity and mortality, and drugs for the prevention and management of these diseases are a large part of the pharmaceutical market. Among these drugs are plant-derived cardiac glycosides, which have been used by various cultures over millennia as both medicines and poisons. We report that digoxin and related compounds activate the NLRP3 inflammasome in macrophages and cardiomyocytes at concentrations achievable during clinical use. Inflammasome activation initiates the maturation and release of the inflammatory cytokine IL-1β and the programmed cell death pathway pyroptosis in a caspase-1–dependent manner. Notably, the same fluxes of potassium and calcium cations that affect heart contraction also induce inflammasome activation in human but not murine cells. Pharmaceuticals that antagonize these fluxes, including glyburide and verapamil, also inhibit inflammasome activation by cardiac glycosides. Cardiac glycoside–induced cellular cytotoxicity and IL-1β signaling are likewise antagonized by inhibitors of the NLRP3 inflammasome or the IL-1 receptor–targeting biological agent anakinra. Our results inform on the molecular mechanism by which the inflammasome integrates the diverse signals that activate it through secondary signals like cation flux. Furthermore, this mechanism suggests a contribution of the inflammasome to the toxicity and adverse events associated with cardiac glycosides use in humans and that targeted anti-inflammatories could provide an additional adjunct therapeutic countermeasure.

Clinical and pathological features of Nerium oleander extract toxicosis in wistar rats

BACKGROUND

Nerium oleander has been widely studied for medicinal purposes for variety of maladies. N. oleander has also been reported having noxious effects because of its number of components that may show signs of toxicity by inhibiting plasma lemma Na+, K+-ATPase. The present study was performed to scrutinize the toxic effect of N. oleander leaves extract and its clinical and pathological features in wistar rats.

RESULTS

Hematological analysis showed significant variations in RBCs count (P = 0.01), Hb (P = 0.001), Hct (P = 0.0003), MCV (P = 0.013), lymphocyte count (P = 0.015), neutrophil count (P = 0.003), monocyte count (P = 0.012) and eosinophil count (P = 0.006). Histopathological studies have shown that in T1 group noticeable infiltration of inflammatory cells was found with low level of vascular damage. In T2 group, increased proportion of binucleated and inflammatory cells, hepatic necrosis, widening of sinusoidal spaces and mild level of vascular damage was observed.

CONCLUSION

Taken together these findings we can conclude that N. oleander leaves extract significantly affects on experimental animals due to its toxicity. Efforts must be exerted to purify different chemical components from extract with no inflammation as this plant is utilized in folk medicine with narrow therapeutic indices.

Oleander toxicosis in equids: 30 cases (1995-2010)

OBJECTIVE

To determine clinical, laboratory analysis, and necropsy findings for equids with oleander toxicosis and to identify factors associated with outcome.

DESIGN

Retrospective case series.

ANIMALS

30 equids.

PROCEDURES

Medical records of equids with detectable concentrations of oleandrin in serum, plasma, urine, or gastrointestinal fluid samples and equids that had not received cardiac glycoside drugs but had detectable concentrations of digoxin in serum were identified via a medical records database search. Descriptive statistics were calculated for medical history, physical examination, laboratory analysis, and necropsy variables. Logistic regression analysis was used to identify physical examination and laboratory analysis factors significantly associated with outcome.

RESULTS

3 of 30 (10.0%) equids died before or immediately after arrival at the hospital. Of the other 27 equids, 23 (85.2%) had gastrointestinal tract abnormalities, azotemia was detected for 19 (70.4%), and a cardiac arrhythmia was ausculted for 18 (66.7%). Mortality rate for all equids was 50.0%; mortality rate for hospitalized equids was 44.4%. The most common cause of death was cardiac dysfunction. Odds of survival to discharge from the hospital were lower for equids with cardiac arrhythmias versus those without arrhythmias and decreased with increasing Hct and serum glucose concentrations. Odds of survival increased with increasing serum chloride concentration and duration of hospitalization.

CONCLUSIONS AND CLINICAL RELEVANCE

Equids with oleander toxicosis frequently had simultaneous gastrointestinal tract, cardiac, and renal problems. Oleander intoxication should be a differential diagnosis for equids with colic in geographic areas where oleander is found, especially when azotemia or cardiac arrhythmias are detected concurrently.

Experimental oleander (Nerium oleander) intoxication in broiler chickens (Gallus gallus)

Dried leaves of oleander were orally given at a single dose of 500 mg/kg body weight to 20 clinically healthy male chickens. Clinical signs of toxicosis began to appear about 1 h after receiving the oleander and included hypersalivation, vomiting, diarrhea, deep depression, and sudden death. Also, hyperemia in the combs and wattles was obviously seen. Electrocardiograms (ECG) were repeatedly recorded at 30 min intervals. ECGs findings included increasing the QRS duration in some birds and various kinds of arrhythmias. Bradycardia was the most frequently detected finding (30.43%). During necropsy, there were congestion and hemorrhages in the visceral organs particularly in heart, liver, kidney, and lung. Histopathology revealed myocardial cell necrosis with hyperemia and hemorrhage, severe diffuse pulmonary congestion and edema, severe renal congestion and hemorrhage with tubular necrosis, and coagulative necrosis of hepatocytes with hyperemia and hemorrhage. There were also congestion, mild epithelial necrosis and desquamation with infiltration of mononuclear inflammatory cells in the proventriculus of all birds. There was also mild to moderate congestion in the intestines with scattered necrosis of surface enterocytes. The lack of information about the toxicity of oleanders in poultry was the main cause for this study. The results suggest that chickens appear to respond to oleander poisoning in a manner similar to other species.

Morphological studies on experimental oleander poisoning in cattle

Oleander poisoning has been reported in man and animals. The present experiments address the gross and microscopic changes due to oleander poisoning in cattle. Minimum lethal doses (50 mg/kg) of oleander leaves were orally administered to three calves in a single dose each of the other three animals received the same lethal dose in three equal parts with 24-h intervals. The lesions in the three animals which received 50 mg/kg in a single dose resulted from the direct effect of the toxin on the vascular endothelial bed and demonstrated as petechial and diffused haemorrhages, congestion, oedema, cell degeneration and inflammatory cell infiltration in the lungs, heart, mesentry, kidneys, serosal and mucosal surfaces of omasum, abomasum and the intestine. The lungs also showed atelectasis, emphysema and disseminated intravascular coagulation. On the other hand, the animals which received divided doses showed lesions due to long-term exposure to the toxic agent and/or as the result of tissue ischaemia. The lungs also showed cell necrosis and mononuclear cell infiltration in the interstitial tissue, and some of the cardiac muscle fibres rather showed fibromyolysis and cell infiltration between muscle fibres, epicardium and endocardium. The intestinal villi showed haemorrhagic, degenerative and necrotic changes and the eosinophils were infiltrated in mucosal and submucosal layers of this organ. Multifocal degenerative and necrotic changes with inflammatory cell infiltration were also present in the liver parenchyma.

Oleander toxicity: an examination of human and animal toxic exposures

The oleander is an attractive and hardy shrub that thrives in tropical and subtropical regions. The common pink oleander, Nerium oleander, and the yellow oleander, Thevetia peruviana, are the principle oleander representatives of the family Apocynaceae. Oleanders contain within their tissues cardenolides that are capable of exerting positive inotropic effects on the hearts of animals and humans. The cardiotonic properties of oleanders have been exploited therapeutically and as an instrument of suicide since antiquity. The basis for the physiological action of the oleander cardenolides is similar to that of the classic digitalis glycosides, i.e. inhibition of plasmalemma Na+,K+ ATPase. Differences in toxicity and extracardiac effects exist between the oleander and digitalis cardenolides, however. Toxic exposures of humans and wildlife to oleander cardenolides occur with regularity throughout geographic regions where these plants grow. The human mortality associated with oleander ingestion is generally very low, even in cases of intentional consumption (suicide attempts). Experimental animal models have been successfully utilized to evaluate various treatment protocols designed to manage toxic oleander exposures. The data reviewed here indicate that small children and domestic livestock are at increased risk of oleander poisoning. Both experimental and established therapeutic measures involved in detoxification are discussed.

Oleander tea: herbal draught of death

A woman died after drinking herbal tea prepared from oleander (Nerium oleander) leaves. This case demonstrates the cross-reactivity between the cardiac glycosides in oleander and the digoxin radioimmunoassay. Digoxin-specific Fab antibody fragments have not been used in oleander poisoning, but these might prove to be lifesaving. Treatment of oleander toxicity is aimed at controlling arrhythmias and hyperkalemia; inactivation of the Na-K ATPase pump, however, can make treatment difficult.