Environmentally‐Friendly Pesticidal Activities ofCallicarpaandKaromiaEssential Oils from Vietnam and Their Microemulsions

Abstract

There is an ongoing interest to identify alternative pesticidal agents to avoid the chronic problems associated with synthetic pesticides. Essential oils have shown promise as botanical pest control agents. In the present study, the essential oils of four members of the Lamiaceae (Callicarpa candicans, C. erioclona, C. macrophylla, and Karomia fragrans; Vietnamese names: Nàng nàng, Tu châu lông mem, Tu châu lá to and Cà diện, respectively), obtained from wild populations in Vietnam, have been obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The essential oils were formulated into microemulsions and the essential oils and their microemulsions were screened for mosquito larvicidal activity against Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and for molluscicidal activity against Pomacea canaliculata. Atractylone and (E)-caryophyllene dominated the volatiles of C. candicans (CCEO) and C. erioclona (CEEO), while the major component in C. macrophylla (CMEO) and K. fragrans (KFEO) was (E)-caryophyllene. The essential oils and microemulsions of both C. candicans and C. erioclona exhibited excellent larvicidal activity against all three mosquito species (Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus) with LC 50 values < 10 μg/mL. Additionally, the larvicidal activity of the microemulsions were significantly improved compared with their free essential oils, especially for C. candicans and C. erioclona. All four essential oils and their microemulsions showed excellent molluscicidal activity with LC 50 < 10 μg/mL. In most cases, the essential oils and microemulsions showed greater pesticidal activity against target organisms than the non-target freshwater fish, Oreochromis niloticus. The in silico studies on physicochemical and ADMET properties of the major components in the studied essential oils were also investigated and most of the compounds possessed a favorable ADMET profile. Computational modeling studies of the studied compounds demonstrated a favorable binding interaction with the mosquito odorantbinding protein target and support atractylone, β-selinene, and caryophyllene oxide as potential inhibitors. Based on the observed pesticidal activities of the essential oils and their microemulsions, the Callicarpa species Supporting information for this article is available on the WWW under

Lignans and some other non-alkaloid compounds from the stem bark of Zanthoxylum rhetsa and their biological activities

“…23 According to the criteria of AutoDock4, lower binding free energy values indicate higher stability for the complex and favoring interaction of ligand within the binding site when it predicts the docking pose. 24,25 Table 5 presents the docking results of studied compounds.…”

“…23 According to the criteria of AutoDock4, lower binding free energy values indicate higher stability for the complex and favoring interaction of ligand within the binding site when it predicts the docking pose. 24,25 As previous studies have reported, the active site of SARS-CoV-2 M pro is constituted by key residues as follows: His41, Met49, Asn142, Gly143, Cys145, His164, Met165, Glu166, Lru167, Pro168, His172, Gln189, Thr190, and Ala191. 26 Binding conformation analysis of PF-07321332 indicate that five H-bonding were created by this compound with Cys145, Glu166, Arg188, Gln189, and Thr190, four among them are essential residues in the active binding region of SARS-CoV-2 M pro .…”

Behavioral, Electrophysiological, and Toxicological Responses of Plutella xylostella to Extracts from Angelica pubescens

“…Antennae of dsNlugOBP-injected BPHs completely lost the ability to sense caryophyllene oxide [55,56]. Nguyen et al reported that caryophyllene oxide was ranked highly as a mosquito odorant-binding protein inhibitor (with larvicidal activity) based on its docking scores, and likely docks similar to permethrin [57]. Thus, we hypothesized that caryophyllene oxide has repellent activity against P. xylostella and may affect the odorant-binding protein of P. xylostella.…”

Chemical Composition, Larvicidal and Molluscicidal Activity of Essential Oils of Six Guava Cultivars Grown in Vietnam

“…(E)-Nerolidol did not exhibit toxicity against Biomphalaria glabrata at a concentration of 100 µg/mL [35]. Essential oils containing (E)-β-caryophyllene as the main constituent exhibited potent molluscicidal activities against Gyraulus convexiusculus and Pomacea canaliculata [42,43,114].…”

“…Protocol 1: Tests for larvicidal activity were performed according to WHO guidelines [129] with modifications according to previous publications [42,43,83,114]. Twentyfive larvae were transferred into 250 mL beakers containing 150 mL of essential oil solutions at concentrations of 100, 50, 25, 12.5, 6.25, 3.125, 1.5, 0.75, 0.375, 0.2, and 0.1 µg/mL; each concentration was repeated four times.…”