Poisonous plants of veterinary and human importance in southern Africa

Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
Journal of Ethnopharmacology (Impact Factor: 3). 08/2008; 119(3):549-58. DOI: 10.1016/j.jep.2008.07.022
Source: PubMed


Southern Africa is inherently rich in flora, where the habitat and climatic conditions range from arid environments to lush, sub-tropical greenery. Needless to say, with such diversity in plant life there are numerous indigenous poisonous plants, and when naturalised exotic species and toxic garden varieties are added the list of potential poisonous plants increases. The economically important poisonous plants affecting livestock and other plant poisonings of veterinary significance are briefly reviewed. In addition, a synopsis of the more common plant poisonings in humans is presented. Many of the plants mentioned in this review are also used ethnobotanically for treatment of disease in humans and animals and it is essential to be mindful of their toxic potential.

Download full-text


Available from: Mary Louise Penrith,
  • Source
    • "observ.). Due to its content of pyrrolizidine alkaloids and flavonoid glycosides of the aerial parts (Wanjala and Majinda, 1999) C. podocarpa is unpalatable and can even cause livestock poisoning (Botha and Penrith, 2008), while seeds of C. podocarpa do contain other alkaloids, which are not further described (Pilbeam et al., 1983) and therefore the impact on seed predators remains unclear. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Plant recruitment can be constrained by processes shaping its seed fate, such as pre- and post-dispersal seed predation, while facilitated by higher seed production and more effective dispersal. These activities are controlled by specific predator and disperser guilds that respond to different microsite conditions such as vegetation density with varying predation and removal rates. In Namibia’s arid rangelands, the native, annual herbaceous legume Crotalaria podocarpa has considerably increased after several years of elevated rainfall, thereby reducing density and vitality of economically important fodder grasses. To investigate whether this proliferation entails the risk of a permanent establishment, we studied pre- and post-dispersal seed predation, as well as primary and secondary seed dispersal of the legume and quantified the impact of different predator groups on post-dispersal seed removal. We experimentally excluded (i) neither vertebrates nor invertebrates, (ii) birds, (iii) vertebrates (birds and rodents), and (iv) vertebrates and large invertebrates on plots with different C. podocarpa density (0–35% cover). Seed predation was mainly caused by invertebrates, with 30% pre-dispersal seed predation in pods and up to 90% post-dispersal seed removal for free seeds on the ground which is the most persistent seed stage. Crotalaria podocarpa density did not affect post-dispersal seed removal or secondary seed dispersal. As main dispersal mode for the study species explosive dehiscence was identified, with seeds reaching dispersal distances of up to 4 m, while wind or rolling dispersal played a minor role. Subsequent secondary dispersal by animals accounted for dispersal distances up to 19 m. Our findings highlight the combined effects of pre- and post-dispersal seed predation to determine the total seed fate. With a contribution of about 370 seeds m-2 to the species persistent soil seed bank, seed numbers seems to be more important for the annual C. podocarpas vagility than the species dispersal ability. Supplemented by seedling fate and adult mortality, this data can contribute to reliably predict the risk of a further spread of the species.
    Perspectives in Plant Ecology Evolution and Systematics 07/2015; 17(5). DOI:10.1016/j.ppees.2015.07.002 · 3.61 Impact Factor
    • "The reasons for livestock ingesting toxic plants are probably universal: drought, introduction of stock into new areas with different plants, livestock grazing on recently burned pastures, accidental ingestion with other plants, and developing a taste for certain plants despite their toxicity and unpalatability (Botha & Penrith 2008; Tokarnia et al. 2012). Differences would, therefore, likely be determined by the availability and abundance of toxic plants, climatic factors and management of both livestock and pastures. "

    Toxicon 11/2014; 90:349-350. DOI:10.1016/j.toxicon.2014.07.006 · 2.49 Impact Factor
  • Source
    • "Datura stramonium contains parasympatholytic alkaloids such as atropine and hyoscine. Humans are extremely susceptible to their effects and hallucinations may occur, and the proverb " blind as a bat, red as a beet, dry as a bone and mad as a hatter " aptly describes atropine poisoning in humans (Botha and Penrith, 2008). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Poisonous plants comprise the third largest category of poisons known around the world. Other than affecting the humans directly, they are the major cause of economic losses in the livestock industry since the advent of civilization. To collect and systematically document the traditional knowledge of poisonous plants of Udhampur District for the benefit of humanity before it is entombed forever. Direct interviews of the informants were conducted and the plants identified as poisonous by them were collected, identified and herbarium sheets were prepared. The data collected through interviews was analysed with two quantitative tools viz. the factor informant consensus and fidelity level. A total of 90 toxic plants were listed from the study site. Most dominant toxic families were Fabaceae, Asteraceae, Solanaceae, Apocynaceae and Euphorbiaceae. Most of the poisonous plants were herbs (57.1%) and the whole plant toxicity was reported to be the highest (32.4%) followed by leaves (23.1%). According to the factor informant consensus, gastrointestinal category had the greatest agreement closely followed by the death category. The most important species on the basis of fidelity level for gastrointestinal category were Cannabis sativa, Cassia occidentalis, Cuscuta reflexa, Euphorbia helioscopia and Euphorbia hirta, for death category were Anagalis arvensis, Embelia robusta and Prunus persica, for dermatological category Euphorbia royleana, Leucanea leucocephala, Parthenium hysterophorus and Urtica dioica, and for sexual illness category were Calotropis procera and Carica papaya. Further phytochemical and pharmacological studies are required to ascertain the toxic components of the poisonous plants, so that they may be utilized for the betterment of future generations.
    Journal of ethnopharmacology 01/2014; 152(1). DOI:10.1016/j.jep.2013.12.058 · 3.00 Impact Factor
Show more