RESUMEN
BACKGROUND OBJECTIVES: Mosquito vectors are a significant cause of pathogen transmission to both animals and humans. Mosquitoes are responsible for transmitting various diseases, including chikungunya, filariasis, West Nile fever, dengue, malaria, and Zika fever, placing approximately 80% of the world's population at risk of infection at any given time. Controlling mosquitoes has become a multifaceted challenge, influenced by diverse environmental factors such as deforestation, urbanization, and climate change on a global scale. For centuries, medicinal plants have been utilized as bioinsecticides to control insect pests. Ziziphus mauritiana, also known as Chinese apple or Indian jujube is a deciduous thorny tree or shrub. Different parts of the Z. mauritiana plant have been traditionally used to treat various common diseases, a practice still prevalent in India and China. METHODS: In the current investigation, the chemical properties of the Z. mauritiana leaf extract were examined through UV-Vis Spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR), and GC-MS Analysis. Second and fourth instar larvae, as well as pupae, of Aedes aegypti and Culex quinquefasciatus were subjected to different concentrations of the methanolic extract of Z. mauritiana for 24 h and 48 h to assess larvicidal and pupicidal activity. RESULTS: The FT-IR spectrum analysis revealed the presence of various functional groups in the chemical compounds extracted from Z. mauritiana , including amines, aromatics, alkanes, alkyls, carbonyls, and carboxylic acids. Additionally, GC-MS analysis identified Isoborneol (25.37%), 4-Acetylbutyric Acid (26.82%), and 2-Vinyl-9-[Beta-D-Ribofuranosyl] Hypoxanthine (24.24%) as the three major phytoconstitutents in the methanol extracts of Z. mauritiana. Regarding the larvicidal activity, the methanolic extract of Z. mauritiana exhibited LC 50 values of 155.67 mg/L and 208.57 mg/L for second instar larvae, and 177.68 mg/L and 252.13 mg/L for fourth instar larvae of Cx. quinquefasciatus and Ae. aegypti, respectively, after 24 h of exposure. For pupicidal activity, the LC 50 values were 502.02 mg/L and 514.99 mg/L on pupae of Cx. quinquefasciatus and Ae. aegypti, respectively, within 24 h. INTERPRETATION CONCLUSION: Overall, the GC-MS analysis provides valuable insights into the chemical composition of the Z. mauritiana extract, highlighting its potential as a natural and eco-friendly alternative for combating insect vectors and contributing to integrated mosquito management programs.
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Insect-borne diseases remain to this day a major source of illness and death worldwide. The resistance to chemical insecticides among mosquito species has been considered as a setback in vector control. Mosquito control programs, botanical origin may have the potential to eliminate eggs and larvae. So, the larvicidal and ovicidal activities of crude benzene, hexane, ethyl acetate, chloroform and methanol extracts of Terminalia chebula were assayed for their toxicity against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in the methanol extract of T. chebula against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus with the LC50 values were 87.13, 93.24 and 111.98 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 48 h post treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the maximum egg mortality (zero hatchability) was observed in the methanol extract of T. chebula at 200 and 250 ppm against A. stephensi, A. aegypti and C. quinquefasciatus showed 100% mortality at 300 ppm. No mortality was recorded in the control. The finding of the present investigation revealed that the leaf extract of Terminalia chebula possesses remarkable larvicidal and ovicidal activity against medically important vector mosquitoes and make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.
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Essential oils extracted by steam distillation from Zingiber officinalis was evaluated for larvicidal and repellent activity against the filarial mosquito Culex quinquefasciatus. The larval mortality was observed after 24 h treated for late third instar. The LC50 value was 50.78 ppm. Skin repellent test at 1.0, 2.0, 3.0, and 4.0 mg/cm2 concentration of Z. officinalis gave 100% protection up to 15, 30, 60, and 120 min. These results clearly reveal that the essential oil of Z. officinalis served as a potential larvicidal and repellent agent against filarial vector C. quinquefasciatus.