Synthesis of Dacus Pheromone, 1,7-Dioxaspiro[5.5]Undecane and Its Encapsulation in PLLA Microspheres for Their Potential Use as Controlled Release Devices

Stavroula A Zisopoulou,Stavroula G Nanaki,Christina K Chatzinikolaou,Dimitra A Lambropoulou,John K Gallos,Eleni Psochia,Dimitrios N Bikiaris,Anna Ofrydopoulou

doi:10.3390/agronomy10071053

Stavroula A Zisopoulou, Stavroula G Nanaki + Show 6 more

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https://doi.org/10.3390/agronomy10071053

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Journal: Agronomy	Publication Date: Jul 21, 2020
Citations: 9	License type: CC BY 4.0

Affiliation: Aristotle University of Thessaloniki

Abstract

Olive fruit fly Dacus oleae is a well-known pest infecting the bark of olive fruit, leading to reduction of extracted olive oil properties. Among chemicals proposed for Dacus oleae population control, pheromone 1,7-dioxaspiro(5.5)undecane (DSU), Dacus pheromone, is considered as a promising agent, which is added in several traps. However, all proposed systems manage to sufficiently deliver DSU for only two weeks. Furthermore, an additional problem is the limited available amount of pheromone to use in such systems. To overcome this, in the present study, a novel synthetic procedure of DSU is described, including only five steps. Intermediate products were studied by High Resolution Mass Spectroscopy Electrospray Ionization (HRMS-ESI) (m/z), while the resulting DSU was further characterized by 1H and 13C-NMR. Synthesized DSU was further encapsulated in poly(L-lactic acid) (PLLA) microparticles in three different concentrations; 5, 10 and 20% w/w. Its successful incorporation was studied by FT-IR, XRD and differential scanning calorimeter (DSC) while two procedures, liquid extraction and solid phase microextraction, followed by GC-MS analysis, was used for quantification of pheromone to microparticles. It was found that microparticles loading was over 85% for all three formulations. Its release showed a prolonged profile for microparticles containing 20% w/w DSU, lasting four weeks, while the quantity of DSU released reached 100%. These microparticles could be appropriate to control Dacus oleae population.

Highlights

Olive oil is considered to be the “green gold” of the Mediterranean Region where Olea europaea L.is thriving
poly(L-lactic acid) (PLLA) of molecular weight of Mn = 20,000 Da and polydispersity index (PDI) ≤ 1.3 was kindly donated from Corbion (CORB.AS) (Spain, Montmelo)
Numerous studies have been reported in the literature thereafter concerning the synthesis of pheromone including asymmetric synthesis [28]

Summary

Introduction

Olive oil is considered to be the “green gold” of the Mediterranean Region where Olea europaea L.is thriving. The olive fruit fly, Bactrocera Oleae or Dacus oleae, is considered to be one of the most known insect pests leading to reduction of olive oil phenolic content [1]. Female flies lay their eggs in the unripe fruits and upon hatching the larvae feed on the fruits, destroying them [2]. Controlling Bactrocera oleae is achieved by the application of chemical pesticides, which are usually a mixture of protein hydrolysate and organophosphorous insecticides [3,4] Their harmful consequences both in human health and the environment led to the development of novel, environment-friendly methods for Dacus population control

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