In vitro acaricidal activity of neem (Azadirachta indica) seed extracts with known azadirachtin concentrations against Rhipicephalus microplus

Abstract

The effect of four extracts from neem seeds (Azadirachta indica) containing 2000, 5000, 9000 and 10,000 ppm of azadirachtin A (AZA), quantified by high-performance liquid chromatography (HPLC) and diluted to 1.25%; 2.5%; 5.0%; 10.0% and 12.8% was verified by in vitro tests with engorged females and larvae of the cattle tick Rhipicephalus microplus. The results from the bioassays with the engorged females showed that the main toxic effect of the extracts was reduction of the reproductive parameters, with a sharp drop in the number of eggs laid and the hatching rate, mainly when the extracts were diluted to 10.0% and 12.8%. The product effectiveness (PE) calculations for all the solutions tested showed that the AZA solution at 10,000 ppm (N10) was the most effective. However, statistical analysis of the PE data obtained for the proportional AZA concentrations in the different diluted extracts showed significance (P<0.05) of the effects included in the model (extract dilution, principle effect (classificatory) of the assay (extract) and the interaction between the two), indicating significant variations due to the dilution, the test and the interaction between the two factors in the tests with engorged females. For solutions N2, N5, and N9, it was not possible to estimate LC(90) values in the dilution range tested. The lowest LC(50) was observed for extract N5, and although extract N10 was the only extract for which the LC(90) could be estimated within the range tested, the LC(50) was higher than for N5 and N9. These results suggest that substances other than AZA present in the extracts influenced the efficacy, especially up to a certain LC range. In the tests with larvae, no mortality was observed, indicating zero effectiveness of all the extracts tested. The results of the tests with engorged females showed that the neem extracts had acaricide activity, inhibiting egg laying and the larval hatching rate. Complementary studies are necessary to develop new methods to isolate and/or identify other substances besides AZA contained in this plant, to enable using products made from it as acaricides.

Acaricidal activity of leaves of Morus nigra against the cattle tick Rhipicephalus microplus

“…The chlorofom extract of the leaves of M. nigra in low concentrations showed noticeable toxicity levels, similar to other plant extracts. Similar results to ours were obtained by Giglioti et al (2011) that evaluated the effect of azadiractin against R. microplus, obtained an efficacy of 61.6% in a 2.5% concentration, concluding that the isolated substance has effect in vitro against ticks. The experiment reported preliminary results, but provided clear evidence those fractions of leaves of M. nigra have a potential pesticide effect and seems to be an alternative control auxiliary for ticks.…”

De-oiled neem cake as potential bio-additive for low-salt raw skin preservation: a process for salinity reduction in tanneries

“…Neem cake was found to be a biocontrol agent against nematode (Jothi et al 2004), and its toxic effect against Aedes albopictus was studied (Nicoletti et al 2010). Azadirachtin A was extracted from neem seed and studied for its acaricidal activity (Giglioti et al 2011). All the above studies clearly show neem seed contains different bioactive compounds, and they possess antimicrobial properties.…”

Phytochemical analysis and acaricidal activity of Aloe arborescens Mill. extracts against Rhipicephalus (Boophilus) microplus

“…(B.) microplus was 94 %, albeit without causing larval mortality (GIGLIOTI et al, 2011). Scopolamine, the active component of Atropa belladonna, caused 93 % mortality of the R.…”

“…(B.) microplus (GIGLIOTI et al, 2011;CAMPOS et al, 2015), Rhipicephalus sanguineus (POLITI et al, 2012), Amblyomma cajennense (CAMPOS et al, 2015), Amblyomma americanum and Dermacentor variabilis (CARROLL et al, 1989), and Hyalomma excavatum (ABDEL-SHAFY;ZAYED, 2002).…”