GC-MS analysis and anti-mosquito activities of Juniperus virginiana essential oil against Anopheles stephensi(Diptera: Culicidae)

Objective: To investigate phytochemicals present in the essential oil from aerial parts of eastern red cedar, Juniperus virginiana(J. virginiana) L.(Cupressaceae) and to determine its killing and repellent activities against larvae, pupae, and adults of the Asian malaria mosquito, Anopheles stephensi(Diptera: Culicidae). Methods: J. virginiana essential oil was extracted by hydrodistillation, and its chemical composition was determined by gas chromatography-mass spectrometry. Seven different logarithmic concentrations of J. virginiana essential oils were used in larvicidal and pupicidal assays. J. virginiana essential oils-impregnated bed nets were applied in a designed animal module to test excito-repellent activity against adult mosquitoes. Results: Fourteen constituents corresponding to 99.98% of J. virginiana essential oils were identified. Five main components were terpinen-4-ol(25.21%), camphor(19.89%), E-3-hexen-1-ol(13.30%), γ-terpinene(7.86%), and l-menthone(2.27%). The LC_(50) and LC_(90) values against larvae of the Anopheles stephensi were 11.693 and 66.140 ppm and for pupae were 9.640 and 40.976 ppm, respectively. In excito-repellency assay, J. virginiana essential oilsimpregnated bed nets provided an average of 54.63% protection for guinea pig and 45.37% mortality for the mosquitoes. Conclusions: Four monoterpenes and one leaf alcohol were identified by gas chromatographymass spectrometry. J. virginiana essential oils showed potent larvicidal, pupicidal, adulticidal, and repellent activities against Anopheles stephensi at acceptable concentrations. Evaluation of bioactivity of identified chemicals(alone or in combination) will provide new eco-friendly substances for mosquito-management programs.

In vitro anti-plasmodial activity of new synthetic derivatives of 1-(heteroaryl)-2-((5-nitroheteroaryl)methylene) hydrazine

Objective:To evaluate new compounds synthesized by integrating quinoline,quinazoline,and acridine rings with the active moiety of(5-nitroheteroaryl)methylene hydrazine.Methods:A new series of compounds(1a,1b,2a,2b,3a,and 3b)were synthesized and evaluated for cytotoxicity against COS-7 cells using the MTT assay.In vitro anti-plasmodial activity of the compounds was measured against CQ-sensitive(3D7)and CQ-resistant(K1)Plasmodium(P.)falciparum strains.β-hematin assay was performed to assess the inhibitory effects ofβ-hematin formation for new compounds.Results:The synthetic compounds had anti-plasmodial activity against blood-stage of 3D7[IC50=(0.328-5.483)μM]and K1[IC50=(0.622-7.746)μM]strains of P.falciparum,with no cytotoxicity against COS-7 cells in effective doses.Compounds 1a,1b,and 2b were the most effective derivatives against P.falciparum 3D7 and K1 strains.Based on theβ-hematin assay,the inhibition ofβ-hematin formation is the main mechanism of the inhibitory effect of these compounds.Conclusions:The synthetic compounds could inhibit the erythrocytic stages of CQ-sensitive and resistant P.falciparum strains without toxicity towards mammalian cells.Compounds 1b,2a,and 2b had comparable anti-plasmodial activity against both CQ-sensitive(3D7)and resistant(K1)P.falciparum strains.These compounds may be promising lead structures for the development of new anti-malarial drugs.