Improved adulticidal activity against Aedes aegypti (L.), and Aedes albopictus (Skuse), from synergy between Cinnamomum spp. essential oils

Abstract

Improved natural adulticidal agents against mosquito vectors are in urgent need, and essential oils from Cinnamomum plants can assume this role quite readily. Cinnamomum verum, C. cassia, and C. loureiroi essential oils (EOs) were extracted from the barks and evaluated for their chemical composition by GC-MS. The major constituent of the three EOs was cinnamaldehyde. WHO susceptibility tests on individual and combined EOs as well as cinnamaldehyde were conducted against female adults of Aedes aegypti and Aedes albopictus. All EO combinations exhibited a synergistic effect, manifesting a higher toxicity, with a synergistic value ranging from 2.9-6.7. Their increasing mortality value was improved between 16.0 to 41.7%. The highest synergistic effect was achieved by an EO combination of 0.5% C. cassia + 0.5% C. loureiroi, while the highest insecticidal activity was achieved by 2.5% C. verum + 2.5% C. cassia and 1% cinnamaldehyde, with a knockdown and mortality rate of 100% and a KT50 between 0.7-2.1 min. This combination was more toxic to both mosquito species than 1% w/v cypermethrin. These findings demonstrate that cinnamaldehyde and synergistic combinations of C. verum + C. cassia EOs and C. cassia + C. loureiroi EOs have a high insecticidal efficacy against Aedes populations.

The essential oil ofSchinus terebinthifoliusand its nanoemulsion and isolated monoterpenes: investigation of their activity againstCulex pipienswith insights into the adverse effects on non‐target organisms

“…Synergism between major and minor EO components has been reported in many cases, because each oil component, even a minor one, participates in cell penetration, fixation on bio-membranes, distribution and accumulation within bio-systems. [50][51][52] An oil/water nanoemulsion (particle size 41.3 nm.) was prepared from S. terebinthifolius EO using a green hydrothermal procedure without toxic chemical solvents.…”

“…In this investigation, crude EO showed more potent insecticidal bioactivity compared with each individual terpene, indicating a possible synergistic interaction between major and minor EO components. Synergism between major and minor EO components has been reported in many cases, because each oil component, even a minor one, participates in cell penetration, fixation on bio‐membranes, distribution and accumulation within bio‐systems 50–52 …”

Potensi Aromaterapi Jeruk Purut (Citrus hystrix DC.) sebagai Adultisida terhadap Aedes aegypti (Linn.) Dewasa

“…Berdasarkan penelitian terdahulu diketahui bahwa kombinasi antara minyak atsiri dari beberapa bahan alam memiliki toksisitas lebih tinggi dibandingkan dengan insektisida kimia. 40,41 Penelitian lainnya menunjukkan bahwa efek mortalitas nyamuk yang ditimbulkan paska aplikasi minyak atsiri akan bergantung pada konsentrasi yang diberikan. Efek yang ditimbulkan juga bervariasi, beberapa minyak atsiri akan menimbulkan efek mortalitas pada dosis yang lebih tinggi, sedangkan minyak atsiri lainnya memberikan efek mortalitas pada dosis rendah sebagaimana ditunjukkan pada penelitian ini.…”

“…45 Efek mortalitas nyamuk tidak hanya dipengaruhi oleh faktor kandungan senyawa maupun konsentrasi, akan tetapi juga oleh durasi paparan. Durasi paparan yang singkat hanya mampu menyebabkan nyamuk pingsan dan tidak menimbulkan kematian setelahnya, 40 sedangkan durasi paparan yang lama akan menyebabkan mortalitas lebih tinggi. 46 Oleh karena itu, perlu dilakukan estimasi waktu paparan untuk mendapatkan efektifitas mortalitas yang maksimal.…”