Acaricidal, insecticidal, and larvicidal efficacy of fruit peel aqueous extract of Annona squamosa and its compounds against blood-feeding parasites

Plant products may be alternative sources of parasitic control agents, since they constitute a rich source of bioactive compounds that are eco-friendly and nontoxic products. The plant extracts are good and safe alternatives due to their low toxicity to mammals and easy biodegradability. In the present study, fruit peel aqueous extract of Annona squamosa (Annonaceae) extracted by immersion method exhibited adulticidal activity against Haemaphysalis bispinosa (Acarina: Ixodidae) and the hematophagous fly, Hippobosca maculata (Diptera: Hippoboscidae), and larvicidal activity against the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae), Anopheles subpictus, and Culex quinquefasciatus (Diptera: Culicidae). The chemical composition of A. squamosa fruit peel aqueous extract was analyzed by gas chromatography-mass spectrometry. The major chemical constituent of peel aqueous extract of A. squamosa was identified as 1H- cycloprop[e]azulen-7-ol decahydro-1,1,7-trimethyl-4-methylene-[1ar-(1a alpha,4a alpha, 7 beta, 7 a, beta, 7b alpha)] (28.55%) by comparison of mass spectral data and retention times. The other major constituents present in the aqueous extract were retinal 9-cis- (12.61%), 3,17-dioxo-4-androsten-11alpha-yl hydrogen succinate (6.86%), 1-naphthalenepentanol decahydro-5-(hydroxymethyl)-5,8a-dimethyl-y,2-bis(methylene)-(1 alpha,4a beta,5 alpha,8a alpha) (14.83%), 1-naphthalenemethanol decahydro -5-(5-hydroxy-3-methyl-3-pentenyl)- 1,4a-di methyl - 6-methylene -(1S-[1 alpha, 4a alpha, 5 alpha(E), 8a beta] (4.44%), (-)-spathulenol (20.75%), podocarp-7-en-3-one13 beta-methyl-13-vinyl- (5.98%), and 1-phenanthrene carboxaldehyde 7-ethenyl-1,2,3,4,4a,4,5,6,7,9,10,10a-dodecahydro-1,4a,7-trimethyl-[1R-(1 alpha,4a beta.4b alpha,7 beta, 10a alpha)]-(5.98%). The adult and larval parasitic mortalities observed in fruit peel aqueous extract of A. squamosa were 31, 59, 80, 91, and100%; 27, 42, 66, 87, and 100%; and 33, 45, 68, 92, and 100% at the concentrations of 250, 500, 1,000, 1,500, and 2,000 ppm, respectively, against Haemaphysalis bispinosa, Hippobosca maculata, and R. microplus. The observed larvicidal efficacies were 36, 55, 72, 92, 100% and 14, 34, 68, 89, and 100% at 200, 400, 600, 800, and 1,000 ppm, respectively, against A. subpictus and C. quinquefasciatus. The highest parasite mortality was found after 24 h of exposure against Haemaphysalis bispinosa (LC50 = 404.51 ppm, r (2) = 0.890), Hippobosca maculata (LC50 = 600.75 ppm, r (2) = 0.983), the larvae of R. microplus (LC50 = 548.28 ppm, r (2) = 0.975), fourth-instar larvae of A. subpictus (LC50 = 327.27 pm, r (2) = 0.970), and C. quinquefasciatus (LC50 = 456.29 ppm, r (2) = 0.974), respectively. The control (distilled water) showed nil mortality in the concurrent assay. The chi (2) values were significant at p < 0.05 level. Therefore, the eco-friendly and biodegradable compounds from fruit peel aqueous extract of A. squamosa may be an alternative to conventional synthetic chemicals, particularly in integrated approach for the control of Haemaphysalis bispinosa, Hippobosca maculata, R. microplus, and the medically important vectors A. subpictus and C. quinquefasciatus.