Browsing by Author "Aberathna, A.A.A.U."

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    Comparative study on larvicidal activity of green synthesized silver nanoparticles and Annona glabra (Annonaceae) aqueous extract to control Aedes aegypti and Aedes albopictus (Diptera: Culicidae)
    (Heliyon 6, 2020) Amarasinghe, L.D.; Wickramarachchi, P.A.S.R.; Aberathna, A.A.A.U.; Sithara, W.S.; De Silva, C.R.
    The present study reports mosquito larvicidal potential of green synthesized silver nanoparticles by using Annona glabra leaves (An-AgNPs). Synthesized An-AgNPs were characterized by Ultraviolet-Visible spectroscopy (UVVIS), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS) technique and Fourier transform infrared spectroscopy (FTIR). Colur change from pale yellow to brick red of the plant extract and AgNO3 solution indicated the formation of An-AgNPs initially. Surface Plasmon Resonance (SPR) band at 435 nm in the UV-Vis confirmed the formation of An-AgNPs. SEM images showed that An-AgNPs were spherical in shape. FTIR proved that An-AgNPs were functionalized with biomolecules in A. glabra leaves. Based on DLS analysis the average size range of synthesized An-AgNPs was determine to be 10–100 nm and 100–1000 nm. Third instar larvae of dengue vector mosquitoes, Aedes aegypti and Aedes albopictus were subjected to larvicidal bioassays in a range of concentrations of An-AgNPs and A. glabra crude aqueous leaf extract (2–10 mg/L). AnAgNPs exhibited very high larvicidal activity against dengue vector mosquito larvae; LC50 value for Ae. aegypti at 24 h exposure to An-AgNPs (Plant extract: AgNO3 1 : 10) 5.29 mg/L; An-AgNPs (Plant extract: AgNO3 2 : 10) 2.43 mg/L while LC50 value for Ae. albopictus at 24 h exposure to An-AgNPs (Plant extract: AgNO31:10) 3.02 mg/ L; An-AgNPs (Plant extract: AgNO3 2:10) 2.51 mg/L. LC50 values obtained for A. glabra leaf extract tested against Ae. aegypti and Ae. albopictus are 5.94 mg/L and 5.00 mg/L respectively at 24-hour exposure. This study further revealed that Ae. albopictus is more susceptible than to Ae. aegypti to a given concentration of An-AgNPs and to crude aqueous leaf extract of A. glabra. Larvicidal effect of An-AgNPs is superior to the crude aqueous leaf extract of A. glabra. An-AgNPs is a potent larvicide for dengue vector control.
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    Potential of bio fabricated Annona glabra - silver nanoparticles to control Aedes aegypti and Aedes albopictus
    (, Proceedings of the 1st International Conference on Frontiers in Chemical Technology, Institute of Chemistry Ceylon, 2020) Aberathna, A.A.A.U.; Amarasinghe, L.D.; Sithara, W.S.; Wickramarachchi, S.; De Silva, C.R.
    Bio synthesized silver nanoparticles using Annona glabra leaf extract (An-AgNPs) as the reducing and stabrlizing agent were assessed as a novel larvicide against dengue vector mosquito larvae. The fresh leaves of A. glabra were crushed well and heated with distilled water under 70 0C for I hour. The supernatant was mixed (10% and 20% v/v of total volume) with 5 mM AgNO, to synthesize AnAgNPs. Formation ofAn-AgNPs were confirmed bythe color change and by appearance ofSPR peak in the Uv-vis spectrum and characterized by Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared spectroscopy (FTIR). lhe larvicidal activity of An-AgNPs was assessed against the third instar larvae of Ae. aegypti ^nd, Ae. albopictus, under the laboratory conditions (2 -10 mg/L). The change ofsolution color from yellow to dark brown/black and the SPR band at 435 nm confirmed the formation of An-AgNPs. According to SEM; An-AgNPs were spherical in morphology. FTIR analysis detected that An-AgNPs are capped and stabilized with biomolecules of A. glabraleaf ltZl9 (C=O stretching), 1366 (CH2 bending) and 3500-3200 (N-H and O-H stretching) and l2l7 cm-' (C-O stretching)i. The LCro of An-AgNPs (10%) and An-AgNPs (20%)againstthethirdinstarslarvaeofAe.aeglptiafter24hourswere5.2gand2.43mglland of Ae. albopictus were 3.02 and 2.51 mg/L respectively. The LC* of An-AgNPs (I0%) and An-AgNPs (20%)againstthethirdinstarslarvaeof Ae.aegyptiafter48hourswerel.5l andl.lT mg/Landof Ae. albopictus were 1.14 and 2.i0 mg/L respectively. The LC,n ofleafcrude plant extract against the third instars larvae of Ae. aegTpti after 24 and 48 hours were 5.9455 and 3.5485 mg/L and for the third instars iaruae of Ae. albopictus were 5.0040 arrd2.7346 mg/L respectivdy. This study shows that AnAgNPs is efficient in controlling mosquito larvae.