LARVICIDAL ACTIVITY OF AMARANTHUS HYBRIDUS EXTRACT AND BIO-SYNTHESIZED COPPER NANOPARTICLES AGAINST MOSQUITO VECTORS

This research covers the synthesis and characterization of Cu nanoparticles using leaf extract of Amaranthus hybridus and the larvicidal evaluation of Amaranthus hybridus and Cu nanoparticles. Nanoparticles are an important area in biotechnology that has been attracting interest recently. The bottom-up method of synthesizing nanoparticles using plant extract (green synthesis) was adopted for this study. In this study, copper nanoparticles were successfully synthesized using the leaf extract of African spinach and characterized using various instruments. The FTIR analysis reveals the presence of various functional groups, such as the O-H (hydroxy) group, which was observed at 3363 cm⁻¹; the O=C (carbonyl) group, which appears at 1633 cm⁻¹; the sp³ C-H peak, which appears at 2924 cm⁻¹; C-C at 1014 cm⁻¹; and the Cu-O peak, which was observed at 676 cm⁻¹. A similar peak was not observed on the FTIR of Amaranthus hybridus. The SEM analysis shows crystalline irregular morphology. While the XRD analysis shows a face-centered cubic crystalline (FCC) shape, the size of the Cu nanoparticles was calculated to be 18.61 nm. The larvicidal activity of Amaranthus hybridus shows lethal concentration (LC) against Culex larvae; for the first instar, LC50 was found to be 40.42 mg/L, and LC90 was 82.08 mg/L. Second instar LC50 was 43.75 mg/L, and LC90 was 85.42 mg/L. For third/fourth instar, LC50 was 42.40 mg/L, while LC90 was 82.40 mg/L. Lethal dose/lethal concentration against Anopheles (LC50) for all instars was 32.86, 47.20, and 43.20 mg/L, respectively. LC90 was found to be (70.35, 87.20, 83.20) mg/L. The larvicidal activity of Cu NPs was calculated, and LC50 against Culex was found to be 22.20, 26.05, and 30.97 mg/L, respectively, and LC90 was found to be 42.20, 49.30, and 63.23 mg/L. While the LC50 of Anopheles larvae was found to be (28.84, 36.07, 35.40) mg/L and the LC90 was (52.09, 71.79, 64.60) mg/L, the correlation for both Culex and Anopheles’ larvae was significant for all instars.