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 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.

Use of Essential Oils for the Control of Anthracnose Disease Caused by Colletotrichum acutatum on Post-Harvest Mangoes of Cat Hoa Loc Variety

“…Bark EOs of C. cassia have trans-cinnamaldehyde (42.4–90.6%), cinnamic acid (5.5–43.1%), methoxy-cinnamaldehyde (3.5–13.8%), and cynnamyl acetate (1.0–5.4%) as the main compositions [ 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. C. loureirii bark EOs commonly contains four main components, namely, trans-cinnamaldehyde (50.2–92.9%), α-copaene (2.1–21.3%), α-guaiene (3.4–9.3%), and β-cadinene (4.1–7.7%) [ 31 , 32 , 33 , 34 , 35 , 36 ]. C. verum varieties are grouped into two chemotypes according to their main components in EOs: eugenol and safrole chemotype [ 23 , 36 ].…”

“…C. verum varieties are grouped into two chemotypes according to their main components in EOs: eugenol and safrole chemotype [ 23 , 36 ]. Bark EOs of eugenol chemotype usually have four marker compounds, namely, trans-cinnaldehyde (50.5–89.3%), cinnamyl acetate (1.5–8.8%), eugenol (0.4–8.8%), and 1,8-cineole (1.0–4.6%) [ 24 , 32 , 34 , 37 , 38 ]. Safrole chemotype often contains two fingerprint compounds in bark EOs, namely, trans-cinnamaldehyde (52.5–74%) and safrole (2–10.8%) [ 23 , 39 ].…”

Chemical Composition of Cinnamomum verum Leaf and Flower Essential Oils and Analysis of Their Antibacterial, Insecticidal, and Larvicidal Properties

“…Likewise our results also observed significant larvicidal potential of the C. verum essential oils; unlike their insecticidal property, the higher activities were observed for the LEO compared to the FEO. Previously, the bark essential oils of C. cassia, C. verum, C. loureiroi [33], and C. osmophloeum [34,35] were observed against the larvae of different species of mosquitoes. It is, thus, possible that the larvicidal properties of these essential oils may be enhancing the value of C. verum essential oils as a mosquito control agent.…”

Bioactivity and safety evaluations of Cupressus sempervirens essential oil, its nanoemulsion and main terpenes against Culex quinquefasciatus Say

“…In the literature, synergism between major and minor constituents has frequently been reported, which is the case herein. This synergy may be between EO mixtures or between components of the same EO, where each component, even if it is a minor constituent, participates in cell penetration, fixation on biomembranes and distribution within living cells (Nenaah et al 2015;Caesar and Cech 2019;Aungtikun and Soonwera 2021;Kim et al 2021).…”