New Eugenol Derivatives with Enhanced Insecticidal Activity.

Maria José G Fernandes,David M Pereira,Renato B Pereira,M Sameiro T Gonçalves,A Gil Fortes,Elisabete M S Castanheira

doi:10.3390/ijms21239257

Abstract

Eugenol, the generic name of 4-allyl-2-methoxyphenol, is the major component of clove essential oil, and has demonstrated relevant biological potential with well-known antimicrobial and antioxidant actions. New O-alkylated eugenol derivatives, bearing a propyl chain with terminals like hydrogen, hydroxyl, ester, chlorine, and carboxylic acid, were synthesized in the present work. These compounds were later subjected to epoxidation conditions to give the corresponding oxiranes. All derivatives were evaluated against their effect upon the viability of insect cell line Sf9 (Spodoptera frugiperda), demonstrating that structural changes elicit marked effects in terms of potency. In addition, the most promising molecules were evaluated for their impact in cell morphology, caspase-like activity, and potential toxicity towards human cells. Some molecules stood out in terms of toxicity towards insect cells, with morphological assessment of treated cells showing chromatin condensation and fragmentation, which are compatible with the occurrence of programmed cell death, later confirmed by evaluation of caspase-like activity. These findings point out the potential use of eugenol derivatives as semisynthetic insecticides from plant natural products.

Highlights

Due to the exponential increase in population, it is necessary to ensure that agricultural production follows the resulting food needs
The intensive use of synthetic pesticides has resulted in damage to the environment, health hazards, and loss of biodiversity [4,5], so it is necessary to adopt less harmful strategies that can include the use of natural-based pesticides, which will result in a healthy environment and sustainable agriculture [6,7]
4-Allyl-2-methoxyphenol, eugenol 1 was obtained by hydrodistillation from clove to a high degree of purity (≥95%), as confirmed by its 1H NMR spectrum, and used in the synthesis of six O-alkylated derivatives (2a–f) and five oxiranes (3a–e), as shown in Scheme 1

Summary

Introduction

Due to the exponential increase in population, it is necessary to ensure that agricultural production follows the resulting food needs. The need for the prevention and control of plant diseases, as well as insect pests, is a crucial issue facing crop protection. The most common strategy for controlling these issues has depended on the use of conventional pesticides, most of which are synthetic pesticides, including insecticides [1,2,3]. The intensive use of synthetic pesticides has resulted in damage to the environment, health hazards, and loss of biodiversity [4,5], so it is necessary to adopt less harmful strategies that can include the use of natural-based pesticides, which will result in a healthy environment and sustainable agriculture [6,7]. Owing to the structural diversity and biological activities of natural products, they could be rich sources of inspiration for the design optimization of active principles in formulation development [11,12]

Methods

Results

Discussion

Conclusion