Occupational asthma and rhinoconjunctivitis caused by senna

Effects of long-term administration of Senna occidentalis seeds on the hematopoietic tissue of rats

Senna occidentalis (S. occidentalis) is a toxic leguminous plant that contaminates crops and has been shown to be toxic to several animal species. All parts of the plant are toxic, but most of the plant's toxicity is due to its seeds. Despite its toxicity, S. occidentalis is widely used for therapeutic purposes in humans. The aim of the present work was to investigate, for the first time, the effects of the chronic administration of S. occidentalis seeds on hematopoietic organs, including the bone marrow and spleen. Fifty male Wistar rats were divided into five groups of 10 animals. Rats were treated with diets containing 0% (control), 0.5% (So0.5), 1% (So1), or 2% (So2) S. occidentalis seeds for a period of 90 days. Food and water were provided ad libitum, except to pair-fed (PF) group which received the same amount of ration to those of So2 group, however free of S. occidentalis seeds. It was verified that rats treated with 2% S. occidentalis seeds presented changes in hematological parameters. The blood evaluation also showed a significant decrease of the Myeloid/Erythroid (M/E) ratio. Chronic treatment with S. occidentalis promoted a reduction in the cellularity of both the bone marrow and spleen. Additionally, we observed changes in bone marrow smears, iron stores and spleen hemosiderin accumulation. Histological analyses of bone marrow revealed erythroid hyperplasia which was consistent with the increased reticulocyte count. These findings suggest that the long-term administration of S. occidentalis seeds can promote blood toxicity.

Toxicology and carcinogenesis study of senna in C3B6.129F1-Trp53 tm1Brd N12 haploinsufficient mice

Senna is a pod or leaf of Senna alexandrina P. Mill and is used as a stimulant laxative. In the large intestine, bacterial enzymes reduce sennosides to rhein-9-anthrone, the active form for the laxative effect. To determine the potential toxic effects of senna, a 5-week dose range finding study in the C57BL/6N mouse and a 40-week toxicology and carcinogenesis study in the C3B6.129F1-Trp53 (tm1Brd) N12 haploinsufficient (p53(+/-)) mouse were conducted. In the 5-week study, C57BL/6N mice were exposed to up to 10,000 ppm senna in feed. Increased incidences of epithelial hyperplasia of the cecum and colon were observed in males and females exposed to 5,000 or 10,000 ppm senna. These intestinal lesions were not considered to be of sufficient severity to cause mortality and, thus, in the p53(+/-) mouse 40-week study, the high dose of 10,000 ppm was selected. Significant increases in the incidences of epithelial hyperplasia of the colon and cecum were observed at 10,000 ppm in p53(+/-) males and females, and the incidence of hyperplasia of the colon was significantly increased at 3,000 ppm in females. In conclusion, the large intestine was the major target of senna-induced toxicity in both wild-type and the p53(+/-) mouse model. There was no neoplastic change when senna was administered to p53(+/-) mouse.

An evidence-based systematic review of senna (Cassia senna) by the Natural Standard Research Collaboration

An evidence-based systematic review, including written and statistical analysis of scientific literature, expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

IgE-mediated sensitisation, rhinitis and asthma from occupational exposures. Smoking as a model for airborne adjuvants?

OBJECTIVE

Airborne pollutants with adjuvant effect, called airborne adjuvants, may promote IgE-sensitisation and development of allergic airway diseases. Smoking and occupational allergen exposures were reviewed to establish a general and verified framework for hazard identification and risk assessment of adjuvant effects of airborne pollutions.

METHODS

The relative risks and the attributable risks of adjuvant effect of smoking were determined for co-exposures with green coffee and castor beans, ispaghula, senna, psyllium, flour and grain dust, latex, laboratory animals, seafood, enzymes, platinum salts, organic anhydrides, or reactive dyes.

RESULTS

Adjuvant effects of smoking depended on the types of allergen, but not on whether sensitisation or allergy was promoted by atopy-the hereditarily increased ability to increase IgE formation.

CONCLUSION

Promotion of IgE sensitisation in humans and in animals may serve for hazard identification of adjuvant effects. Risk assessment has been based mainly on epidemiological studies, which are sensitive to confounding factors. This highlights the need to develop appropriate animal models for risk assessment.

Occupational airway sensitizers: an overview on the respective literature

BACKGROUND

Worldwide, there is rigorous scientific activity concerning the further development of work safety regulations involving airway-sensitizing substances. Technical directives on hazardous substances are enforced in several countries and are being continuously updated. The European Union has established a code for several occupational substances, now labeled R 42 ("may cause sensitization by inhalation").

METHODS

We present an overview of the literature dealing with allergic occupational asthma. The literature was selected according to criteria of study design and diagnostic test methods. Approximately 300 publications were reviewed including both epidemiological studies and individual case reports.

RESULTS

Airway sensitizers are systematically arranged and separately listed according to chemicals and their origin from animals, plants, and microorganisms. The clinical data as well as threshold limit values (TLV) and R 42 labeling of 250 airway-sensitizing substances are presented.

CONCLUSIONS

The most common sensitizing substances causing occupational asthma were dust of cereal flours, enzymes, natural rubber latex, laboratory animals as well as low molecular substances such as isocyanates and acid anhydrides.

Sensitization and lung function in workers occupationally exposed to natural thickening products

BACKGROUND

Three workers engaged in the manufacture of natural thickener products (Cassia spp., guar, and tamarind flour) were occupationally sensitized to Cassia spp. Therefore, a cross-sectional study on the prevalence of sensitization among and respiratory health of the employees of this plant was conducted.

METHODS AND RESULTS

Sixty-two workers (36 with high, 26 with low exposure) participated in the survey. Skin prick tests and specific IgE tests with extracts of these components revealed that 11.3% were sensitized to Cassia spp. and 9.7% to at least one species of storage mites, with a significantly higher portion of atopic subjects in the sensitized group. Overall, 55% of the subjects reported work-related symptoms (upper and lower airways, eyes, or skin). FVC % pred. was significantly lower in highly exposed workers, while RV % pred. and RV%TLC % pred. were significantly higher in this group. In the multivariate model, sensitization was not a risk factor for impairment of lung function.

CONCLUSIONS

Dust exposure to flours may not only cause allergic sensitization but also induce chronic changes in lung function.