Efficacy and toxicity of thirteen plant leaf acetone extracts used in ethnoveterinary medicine in South Africa on egg hatching and larval development of Haemonchus contortus
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Authors
Adamu, Mathew
Naidoo, Vinny
Eloff, Jacobus Nicolaas
Journal Title
Journal ISSN
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Publisher
BioMed Central
Abstract
BACKGROUND: Helminthiasis is a major limitation to the livestock industry in Africa. Haemonchus contortus is the
singular most important helminth responsible for major economic losses in small ruminants. The high cost of
anthelmintics to small farmers, resistance to available anthelmintics and residue problems in meat and milk
consumed by humans further complicates matters. The use of plants and plant extracts as a possible source of new
anthelmintics has received more interest in the last decade. Our aim was not to confirm the traditional use, but
rather to determine activity of extracts.
Based on our past experience acetone was used as extractant. Because it is cheaper and more reproducible to
evaluate the activity of plant extracts, than doing animal studies, the activity of acetone leaf extracts of thirteen
plant species used traditionally in ethnoveterinary medicine in South Africa were determined using the egg hatch
assay and the larval development test. Cytotoxicity of these extracts was also evaluated using the MTT cellular
assay.
RESULTS: Extracts of three plant species i.e. Heteromorpha trifoliata, Maesa lanceolata and Leucosidea sericea had EC50
values of 0.62 mg/ml, 0.72 mg/ml and 1.08 mg/ml respectively for the egg hatch assay. Clausena anisata; (1.08 mg/ml)
and Clerodendrum glabrum; (1.48 mg/ml) extracts were also active. In the larval development assay the H. trifoliata
extract was the most effective with an EC50 of 0.64 mg/ml followed by L. sericea (1.27 mg/ml). The activities in the larval
development test were generally lower in most plant species than the egg hatch assay. Based on the cytotoxicity
results C. anisata was the least toxic with an LC50 of 0.17 mg/ml, while Cyathea dregei was the most toxic plant with an
LC50 of 0.003 mg/ml. The C. anisata extract had the best selectivity index with a value of 0.10 and 0.08 for the two
assays, followed by H. trifoliata and L. sericea with values of 0.07, 0.07 and 0.05, 0.04. The C. dregei extract had the worst
selectivity index with a value of 0.00019 for both assays.
CONCLUSION: The result of this study indicates which species should be further investigated in depth for isolation of
compounds.
Description
MA participated in the design of the study, carried out field work, prepared
the extracts, participated in all assay, analysed the data and wrote first draft
and subsequent drafts of the manuscript. VN participated in the design and
coordination of the study, supervised the study, analysed the data and
revised the draft manuscript. JNE participated in the design and coordination
of the study, supervised the study and revised the manuscript. All authors
read and approved the final manuscript.
Keywords
Anthelmintic, Ethnoveterinary medicine, Plant species, Haemonchus contortus, In vitro, Toxicity
Sustainable Development Goals
Citation
Adamu et al.: Efficacy and toxicity of thirteen plant leaf acetone extracts used in ethnoveterinary medicine in South Africa on egg hatching and larval development of Haemonchus contortus. BMC Veterinary Research 2013 9:38.