Nematicidal Action of Microencapsulated Essential Oil of Flesh Fingered Citron

Abstract

Flesh fingered citron (FFC) essential oil (EO) is susceptible to volatilisation at room temperature. Therefore, its use as a nematicide requires a controlled release. In the present study, we encapsulated FFC EO in β-cyclodextrin by embedding and investigated release from the capsules compared to unembedded EO. We evaluated the structural and thermal properties of the capsules by SEM and TGA. The loading capacity was 32.67%, and the embedding yield was 96.24%, assuming that a core-to-wall quality ratio of 1 : 6 is optimal for the carrier. Using Caenorhabditis elegans as a model organism, we explored the toxicity of (1) FFC EO microcapsules (MCs) and (2) four key compounds of the EOs. The MCs enabled sustained release, e.g., 77% mortality after 4 h and 100% within an additional half-hour. The four main compounds in EO can each kill nematodes by reducing antioxidant activity. Since microencapsulation can improve FFC EO stability and prevent product loss due to adverse environments exposed to the air, encapsulating FFC EO in MCs has great potential as a new nematicide.