An aqueous extract of Maerua edulis (Gilg &amp; Ben) DeWolf tuber is as effective as a commercial synthetic acaricide in controlling ticks on cattle in vivo

Nyahangare, Emmanuel T.; Mvumi, Brighton M.; Magona, Christopher; Eloff, Jacobus Nicolaas

doi:10.1016/j.indcrop.2017.09.052

Cited by 8 publications

(8 citation statements)

References 49 publications

(56 reference statements)

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“…All compounds isolated from leaves of M. edulis and tested here ( 1 – 6 ) were biologically active against adult bruchid beetles and it is likely therefore that in the absence of other candidates in aqueous extracts, that these compounds explain the biological activity of the crude extracts as used by farmers and the activity of this species to other arthropods ( Mazhawidza and Mvumi, 2017 ; Nyahangare et al, 2017 ). Compounds were tested at concentrations equivalent to those used by farmers highlighting a drawback of using plant chemicals as they may need to be used at high concentrations to be active.…”

Section: Discussionmentioning

confidence: 92%

“…We evaluated the biological activity of a crude extract of M. edulis , along with compounds 1–4 and stachydrine fraction ( 5/6 ) against C. maculatus at concentrations equivalent to those present in a 10%, 1, and 0.1% crude leaf extract, which was in the range of concentrations used by farmers ( Nyahangare et al, 2017 ). After 72 h there were differences in mortality (ANOVA, 19 d.f., P < 0.001) with more of those insects exposed to the crude extract dying than the control group (Tukey’s, P < 0.05) although this was still lower than for insects exposed to the positive control, rotenone (Tukey’s, P < 0.05; Table 3 ).…”

Section: Resultsmentioning

confidence: 99%

“…We report the isolation and structural elucidation of two new and two previously described cinnamoylagmatine derivatives from the leaves of M. edulis a species of plant that is used as a botanical insecticide in southern Africa ( Nyahangare et al, 2012 , 2017 ; Mazhawidza and Mvumi, 2017 ). Although the E -coumaroylagmatine was reported previously this was from a synthesis and so is reported here for the first time from nature.…”

Section: Discussionmentioning

confidence: 99%

“…Maerua edulis plants were collected from Chiredzi district about 430 km East of Harare in Zimbabwe and identified locally as previously reported ( Nyahangare et al, 2017 ). A specimen is deposited in the national herbarium and botanic gardens of Zimbabwe (Voucher specimen recorded as Nyahangare E5).…”

Section: Methodsmentioning

confidence: 99%

“…Maerua edulis (Gilg & Gilg-Ben.) DeWolf (Capparaceae) is a shrub widely distributed in Southern Africa where it has reported antimicrobial and pesticidal activity ( Nyahangare et al, 2012 , 2017 ; Mazhawidza and Mvumi, 2017 ). To date, however, nothing is known about the components that mediate these reported activities limiting the potential to maximize the pest control benefits of M. edulis for smallholder farmers or understand more about the potential toxicity of the genus ( Malami et al, 2014 ; Nyahangare et al, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

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Novel Agmatine Derivatives in Maerua edulis With Bioactivity Against Callosobruchus maculatus, a Cosmopolitan Storage Insect Pest

et al. 2018

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Food security in developing countries is threatened by crop pests and ectoparasites in livestock. Strategies for their management still rely on synthetic pesticides which are not always effective and the active ingredients persist in the environment with negative consequences for beneficial arthropods, farmers and consumers, hence necessitating research on sustainable alternatives. Botanical insecticides are increasingly relevant, typically having lower impacts on users, consumers and the environment. One example is the southern African shrub the Blue bush-berry, Maerua edulis. Recent work reported effective pest control using this plant species against cattle ticks, storage beetles and vegetable pests. However, little is known about the chemistry underlying activity and this is essential to optimize its use. Here, we identified two novel plant chemical structures, the E and Z isomers of cinnamoyl-4-aminobutylguanidine along with the E and Z isomers of 4-hydroxycinnamoyl-4-aminobutylguanidine in the leaves of M. edulis. We isolated these compounds from the leaves and elucidated their chemical structures using various spectroscopic techniques including High Resolution Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy. We also identified a further 11 closely related structures of which 6 are tentatively reported here for the first time. Stachydrine and 3-hydroxystachydrine were also identified in the leaf extract, and occurred at very high concentrations; up to 2% w/w of dry leaves. We tested these two compounds, along with the 4 main cinnamoylamides and the crude M. edulis leaf extract against the cowpea bruchid Callosobruchus maculatus at concentrations equivalent to those present in extracts used by smallholder farmers. Mortality of insects exposed to crude plant extracts after 72 h was significantly higher than the untreated control although still lower than for insects exposed to rotenone, the positive control. The two new compounds and stachydrine showed similar activity to the crude extracts suggesting that these compounds explained the activity of the extract. After 6 days, the mortality of insects exposed to crude extracts and isolated compounds was similar to that recorded with the positive control. The stachydrine fraction and the E and Z isomers of cinnamoyl-4-aminobutylguanidine also inhibited oviposition activity in fecund female beetles. Our data show that methanol extracts of M. edulis were toxic to C. maculatus and inhibited oviposition even at 0.1% w/v so these foliar chemicals may explain the activity of the plant material. We also synthesized the amides which facilitated structural elucidation, produced adequate quantities for testing and demonstrated the potential for commercial synthesis.

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Section: Discussionmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%