Saud Talaq Alerwi*, Naser Ahmed AL-Kenani and Abdullah Alghamdi

Department of Biological Sciences, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia

*Corresponding Author: Saud Talaq Alerwi, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia. Email: salerwi0006@stu.kau.edu.sa

Received: June 16, 2026; Published: July 21, 2026

Background: Dengue fever, transmitted by Aedes aegypti mosquitoes, is a major public health concern in Saudi Arabia. The emergence of insecticide resistance necessitates the development of eco-friendly alternatives. 

Objective: This study aimed to synthesize and characterize silver nanoparticles (AgNPs) using Nepeta deflersiana (N. deflersiana) ethanol extract and evaluate their larvicidal activity against Ae. aegypti fourth-instar larvae. 

Methods: N. deflersiana leaves were collected from Al Baha region, Saudi Arabia. Ethanol extract was prepared by maceration. AgNPs were biosynthesized using 1 mM silver nitrate and characterized by UV-Vis spectrophotometry, SEM, and FTIR. Phytochemical composition was analyzed by GC-MS. Larvicidal bioassays were conducted using the WHO immersion method with five concentrations for crude extract (500-1300 ppm) and AgNPs (0.1-0.9 ppm), Control groups included distilled water. Mortality was recorded after 24 hours, and data were analyzed by probit analysis. 

Results: GC-MS analysis revealed 55 compounds, majorly 17-octadecynoic acid (14.50%), 3-pyridinecarboxaldehyde (9.45%), α-linolenic acid (8.44%), and phytol (7.63%). UV-Vis spectroscopy showed SPR peak at 420-440 nm. SEM revealed spherical nanoparticles (15-45 nm). FTIR confirmed involvement of -OH, C=O, and -NH groups. Crude extract exhibited LC₅₀ of 791.482 ppm and LC₉₀ of 1272.85 ppm. AgNPs showed dramatically enhanced activity with LC₅₀ of 0.301 ppm and LC₉₀ of 1.355 ppm based on probit analysis, representing a 2,630-fold increase in potency. Treated larvae exhibited cuticle melanization, siphon damage, setae destruction, and body shrinkage. 

Conclusion: N. deflersiana-synthesized AgNPs show promising laboratory-based larvicidal activity against Ae. aegypti, offering a potential eco-friendly alternative for further investigation in dengue vector control. Further field evaluations, non-target toxicity assessments, and higher concentration testing are needed before practical application.

Keywords: Nepeta deflersiana; Silver Nanoparticles; Green Synthesis; Aedes aegypti; Larvicidal Activity; Dengue Vector; Saudi Arabia

References

1. Alhaeli A., et al. “The epidemiology of Dengue fever in Saudi Arabia: A systematic review”. Journal of Infection and Public Health2 (2016): 117-124.
2. Altassan KK., et al. “Dengue fever in Saudi Arabia: A review of environmental and epidemiological factors”. Journal of Environmental Health 5 (2019): 18-25.
3. Zaki AM., et al. “Dengue fever in Saudi Arabia: A review”. Journal of Infection and Public Health1 (2008): 14-21.
4. Khan NA., et al. “Clinical profile and outcome of hospitalized patients during first outbreak of dengue in Makkah, Saudi Arabia”. Acta Tropica1 (2008): 39-44.
5. Aldossari MA., et al. “Health issues in the Hajj pilgrimage: A literature review”. Eastern Mediterranean Health Journal 10 (2019): 744-753.
6. Harrison RE., et al. “Chemical insecticides for mosquito control: A review of current challenges”. Pest Management Science6 (2022): 2145-2160.
7. Bornman R., et al. “Maternal exposure to DDT, DDE, and pyrethroid insecticides for malaria vector control and hypospadias in the VHEMBE birth cohort study”. Science of The Total Environment 845 (2022): 157084.
8. Zeledon R., et al. “Insecticide resistance in Aedes aegypti: Current status and management strategies”. Journal of Vector Ecology1 (2024): 1-15.
9. Alami A., et al. “Chemical composition and larvicidal properties of essential oils from wild and cultivated Artemisia campestris L”. The Scientific World Journal 2023 (2023): 5748133.
10. Da Costa MLL., et al. “Oxidative stress induction by essential oil from Piper alatipetiolatum triggers lethality in Culex quinquefasciatus larvae”. Pesticide Biochemistry and Physiology 200 (2024): 105809.
11. Costa RAD., et al. “Exploring natural alkaloids from Brazilian biodiversity as potential inhibitors of the Aedes aegypti juvenile hormone enzyme”. Molecules19 (2023): 6871.
12. Morejón B., et al. “Larvicidal activity of silver nanoparticles synthesized using extracts of Ambrosia arborescens (Asteraceae) to control Aedes aegypti L. (Diptera: Culicidae)”. Journal of Nanotechnology 2018 (2018): 1-10.
13. Raguvaran K., et al. “Eco-friendly synthesis of silver nanoparticles and its larvicidal property against malaria, filariasis, and dengue vectors”. Luminescence 7 (2025): e70012.
14. Thapa A., et al. “Phytofabricated silver nanoparticles formulated from Macropanax undulatus leaf extract: Green synthesis, characterization, biological evaluations, and protein and DNA interactions”. Journal of Molecular Structure 1349 (2026): 143711.
15. Ahmad M., et al. “Ethnobotanical survey of medicinal plants in Al Baha region, Saudi Arabia”. Saudi Journal of Biological Sciences 8 (2021): 4321-4330.
16. Khan S and Ahmad A. “Phytochemical profiling and insecticidal activities of Nepeta species from the Himalayan region”. Journal of Ethnopharmacology 318 (2024): 116-129.
17. Al-Harbi NA., et al. “Chemical composition and biological activities of Meriandra bengalensis from Saudi Arabia”. Saudi Journal of Biological Sciences5 (2023): 103-115.
18. Kumare M., et al. “Phytol-mediated silver nanoparticles: Synthesis, characterization, and larvicidal activity against mosquito vectors”. Materials Today Communications 45 (2025): 109-122.
19. Khanrah J and Rawani A. “Green synthesis of metal nanoparticles using leaf extracts of Mammea americana L. and its efficacy against vector mosquito larvae”. Notulae Scientia Biologicae3 (2025): 12621.
20. Al-Zahrani SH., et al. “Green synthesis of silver nanoparticles using Ocimum basilicum extract and their larvicidal activity”. Saudi Pharmaceutical Journal8 (2023): 101-112.
21. Zhang Y., et al. “Silver nanoparticles: Mechanisms of action against insect pests”. International Journal of Nanomedicine 18 (2023): 2145-2160.
22. Pavela R., et al. “Plant extracts and essential oils for mosquito control: A review of recent advances”. Environmental Science and Pollution Research42 (2022): 63520-63535.
23. da Silva MR., et al. “Larvicidal activity of Lamiaceae plant extracts against Aedes aegypti”. Journal of Medical Entomology2 (2024): 345-356.
24. Qari SH and Aljameeli MM. “In vivo efficacy of date palm pit extract based chromone derivative against Aedes aegypti dengue vectors in Saudi Arabia”. Entomological Research8 (2024): e12745.
25. World Health Organization. “Guidelines for laboratory and field testing of mosquito larvicides”. WHO/CDS/WHOPES/GCDPP/2005.13. Geneva: WHO (2005).
26. Finney DJ. “Probit analysis”. 3^rd Cambridge: Cambridge University Press; (1971).

Citation

Citation: Saud Talaq Alerwi., et al. “Green Synthesis and Characterization of Silver Nanoparticles Using Nepeta deflersiana Extract: A Novel Approach for Larvicidal Control of Aedes aegypti". Acta Scientific Medical Sciences 10.8 (2026): 09-20.

Copyright

Copyright: © 2026 Saud Talaq Alerwi., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.