This study systematically evaluated the efficiency of rose bengal and methylene blue as
photosensitizers against the immature aquatic stages of Anopheles pharoensis. Genetic identification
using the COI partial sequence confirmed the species, and the obtained sequence was submitted to
GenBank (Accession No. PQ346929). Both photosensitizers exhibited 100% mortality in larvae I within
24 h at their highest concentrations, demonstrating strong biocidal activity. LC50 values for rose bengal
increased from 1.50 ppm (24 h) and 1.34 ppm (48 h) in larvae I to 3.83 ppm (24 h) and 3.12 ppm (48 h) in
pupae. Similarly, methylene blue showed LC50 values rising from 1.14 ppm (24 h) and 0.90 ppm (48 h)
in larvae I to 2.91 ppm (24 h) and 2.51 ppm (48 h) in pupae, indicating stage-dependent susceptibility.
Enzymatic responses revealed a progressive increase in acetylcholinesterase (AChE) and glutathione
S-transferase (GST) activity in the developmental stage, suggesting a physiological adaptation to the
photosensitizers. Molecular docking against the AChE protein (PDB ID: 6xyu) confirmed insecticidal
bioactivity, with methylene blue exhibiting superior binding affinity, aligning with the in-vitro larvicidal
results. Furthermore, a Complex GAPI assessment confirmed the environmental sustainability of both
photosensitizers, supporting their potential as eco-friendly alternatives for mosquito control. The use
of Complex GAPI in assessing the environmental sustainability of photosensitizers in mosquito control
represents a novel approach in the field of integrated pest management. This advancement not only
aligns with the principles of green chemistry but also addresses the growing need for sustainable
alternatives to traditional chemical insecticides. These findings highlight the feasibility of utilizing
light-activated photosensitizers for sustainable vector management. |
