Acute mammalian toxicity of four pesticidal plants

Nyahangare, Emmanuel T., Hove, Thokozani, Mvumi, Brighton M., Hamudikuwanda, Humphrey, Belmain, Steven R., Madzimure, James and Stevenson, Philip C. (2012) Acute mammalian toxicity of four pesticidal plants. Journal of Medicinal Plants Research, 6 (13). pp. 2674-2680. ISSN 1996-0875 (doi:10.5897/JMPR11.1767)

Abstract

Many plant species show potential as alternatives to synthetic pesticides but little is known about their acute mammalian toxicity. The single-dose acute oral toxicities of crude aqueous extracts of Strychnos spinosa and Bobgunnia madagascariensis fruits and the foliage of Vernonia amygdalina and Cissus quadrangularis (plant species that are commonly used as pesticides in Southern Africa) were evaluated in BALB/c mice. Plant extracts (up to 75% w/v or v/v) were orally administered to sexually mature mice. Behavioural changes, clinical signs and mortality were monitored for 4 days. Mice that received S. spinosa had generalized tonic muscle spasms and a high mortality of 83%. Those that received B. madagascariensis exhibited signs of buccal and nasal irritation with occasional sneezes during administration and a high mortality of 75% was recorded. C. quadrangularis consumption resulted in much lower mortality of 21% while no clinical signs of toxicity were evident on mice administered V. amygdalina. Chemical analysis showed the presence of secoiridoids in the seedless pulp of S. spinosa. These results indicate that aqueous extracts of S. spinosa and B. madagascariensis fruits and foliage of C. quadrangularis may have deleterious health implications on humans and animals; hence, advice on their safety should accompany promotion of their use.

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