Larvicidal activities of family Anacardiaceae on Aedes mosquitoes (Diptera: Culicidae) and identification of phenolic compounds

Background: The mosquito vector control program still relies on the use of synthetic insecticides causes resistance in vector species. The application of alternative strategies using phytochemical sources is a possible way to eliminate the vector of dengue, Chikungunya and Zika viruses. In this study, we tested the larvicidal efficacy of Anacardium occidentale (Cashew), Mangifera indica (Mango), Gluta renghas (Rengas) and Melanochyla fasciculiflora (Rengas) methanolic extract from stems against Aedes albopictus and Ae. aegypti. Methodology: The stem of A. occidentale, Mn. indica, G. renghas and Ml. fasciculiflora was extracted using Soxhlet extraction using methanol as a solvent. These crude extracts were tested on Ae. aegypti and Ae. albopictus using WHO larval bioassay. The chemical compounds were screening, and the fractions were confirmed using UPLC. Results: Our study found Gluta renghas exhibited the strongest larvicidal efficacy toward Ae. albopictus at 607 mg/L and 976 mg/L for Ae. aegypti. In terms of order, Gl. renghas exhibited significantly best effectiveness, followed by Mn. indica, Ml. fasciculiflora and An. occidentale on both Aedes species. Screening results on chemical compounds found the presence of saponins, tannins, alkaloids, reducing sugar, flavonoid, and steroid but the absence of alkaloids in all four plants. The fraction by UPLC confirmed the existence of five prominent peaks of quercetin at a retention time of 4.171-4.358 min and apigenin derivatives at 5.010 min in Gl. renghas. However, the higher concentration of apigenin and quercetin in the plant is not a contributing factor in the effectiveness of phytochemical on Aedes mosquitoes. Thus, suggested the larvicidal effects were derived from the combination and synergistic action between cumulative quercetin and apigenin compounds. Conclusion: Gluta renghas had shown its ability to become the promising bio-larvicides due to the lower dose needed to cause the lethal effect to mosquito larvae. This finding is valuable for bio-larvicides to be integrated with the vector control program. (c) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study demonstrates that Gluta renghas shows the strongest larvicidal efficacy against Aedes albopictus and Ae. aegypti, making it a promising bio-larvicide. Chemical analysis revealed the presence of various active compounds, but the concentration of quercetin and apigenin in the plant is not the main factor affecting its mosquito-killing effect.