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

Jirapon Aungtikun,Mayura Soonwera

doi:10.1038/s41598-021-84159-z

Jirapon Aungtikun, Mayura Soonwera

Open Access

https://doi.org/10.1038/s41598-021-84159-z

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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 to 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 and 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.

Highlights

Most chemical insecticides exert some serious negative effects on human health, the environment, pollinators, parasitic and predatorial insects
Many studies have reported the efficacy of Cinnamomum essential oils (EOs) against mosquitoes, but none has focused on the possible synergy in adulticidal activity between two combined EOs from Cinnamomum spp
The highest essential oil yield was obtained from C. cassia (1.12% v/w), followed by C. verum (1.01% v/w) and C. loureiroi (0.82% v/w)

Summary

Introduction

Most chemical insecticides exert some serious negative effects on human health, the environment, pollinators (bee, bumble bee, carpenter bee, stringless bee etc.), parasitic and predatorial insects (braconids, trichogramma, and ichneumonids). More than 122 EOs from 26 plant families have a mosquito control efficacy, such as those from Alpinia galanga, Anethum graveolens, Amomum villosum, Amomum krervanh, Artemisia verlotiorum, Cannabis sativa, Cananga odorata, Carlina acaulis, Curcuma zedoaria, Cymbopogon citratus, Cymbopogon nadus, Eucalyptus globulus, Foeniculum vulgare, Illicium verum, Lavandula dentata, Pimpinella anisum, Ruta chalepensis, Zanthoxylum limonella, Zingiber cassumunar, and Zingiber mekongense They are toxic to the adults and larvae of Ae. aegypti, Ae. albopictus, Anopheles dirus, and Culex quinquefasciatus[24,25,26,27,28,29,30,31,32,33,34,35]. EO combinations that showed a highly synergistic effect can be developed into effective adulticidal agents for controlling and managing Aedes mosquitoes in urban and rural areas as well as for controlling dengue diseases and other vector-borne d iseases[31,36]

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