Abstract

ABSTRACT
Objectives: investigation of the anticholinesterase and acaricidal activities of two plants of family Aizoaceae; T. portulacastrum L. (TP) and A. canariensis L. (AC) against Rhipicephalus annulatus tick.
Material and Methods: Acaricidal activity was evaluated using adult and larval immersion tests of different concentrations (12.5, 25, 50, 100 and 150 mg/mL). Anti-acetyl cholinesterase (AChE) activity of plant extracts and isolated compounds were performed spectrophotometrically using different concentrations (0.25, 0.5 and 1 mg/mL).
Results: From 50 mg/mL and higher, T. portulacastrum crude hydroalcoholic extract showed 100% adult and larval mortality (P ≤0.05) while A. canariensis L. showed only 20% and 25% respectively (P ≥ 0.05). The bioassay-guided fractionation of the active T. portulacastrum crude hydroalcoholic extract was performed using solvent partitioning and column chromatography. Fractions and pure isolates were subjected to the acaricidal activity and both n-hexane fraction and the unsaponifiable matter (USM) retained a significant activity in immersion tests its column chromatography led to the isolation of a β-sitosterol (1)–stigmasterol (2) mixture (1:1). Ethyl acetate fraction showed 70% adult mortality and the compound 20-hydroxyecdysone (3) was isolated as a major compound.
Conclusions: T. portulacastrum L. contains secondary metabolites with acaricidal activity that provides promising natural products for controlling bovine tick

Key words: Keywords: Aizoaceae, Trianthema portulacastrum, Aizoon canariensis, Rhipicephalus annulatus, Steroids, Anti-acetyl cholinesterase.