Biological evaluation of 1,3-benzodioxole acids points to 3,4-(methylenedioxy) cinnamic acid as a potential larvicide against Aedes aegypti (Diptera: Culicidae)

Aedes aegypti serves as the primary vector for viruses like dengue, Chikungunya, Zika, and yellow fever, posing a significant public health challenge in Brazil. Given the absence of approved vaccines for these diseases, effective mosquito control becomes paramount in preventing outbreaks. However, currently available chemical insecticides face issues related to toxicity and the emergence of resistance, necessitating the exploration of new active compounds. Drawing inspiration from natural products, we identified the 1,3-benzodioxole group as a key pharmacophore associated with insecticidal activity. Therefore, this study aimed to synthesize and assess the larvicidal activity of 1,3-benzodioxole acids against Ae. aegypti, as well as their toxicity in mammals. Among the compounds evaluated, 3,4-(methylenedioxy) cinnamic acid (compound 4) demonstrated larvicidal activity. It exhibited LC₅₀ and LC₉₀ values of 28.9 ± 5.6 and 162.7 ± 26.2 μM, respectively, after 24 h of exposure. For reference, the positive control, temephos, displayed both LC₅₀ and LC₉₀ values below 10.94 μM. These findings underline the significance of the 3,4-methylenedioxy substituent on the aromatic ring and the presence of a double bond in the aliphatic chain for biological activity. Furthermore, compound 4 exhibited no cytotoxicity towards human peripheral blood mononuclear cells, even at concentrations up to 5200 μM. Lastly, in mice treated with 2000 mg kg⁻¹, compound 4 showed mild behavioral effects and displayed no structural signs of toxicity in vital organs such as the kidney, liver, spleen, and lungs.