Encapsulation, release and insecticidal activity of Pongamia pinnata (L.) seed oil

Aloke Purkait,Ayan Mukherjee,Dipak Kumar Hazra,Kusal Roy,Pabitra Kumar Biswas,Ramen Kumar Kole

doi:10.1016/j.heliyon.2021.e06557

Aloke Purkait, Ayan Mukherjee + Show 4 more

Open Access

https://doi.org/10.1016/j.heliyon.2021.e06557

Copy DOI

Abstract

Pongamia pinnata (L.) seed oil is effective for its insecticidal and larvicidal activities. However, its low aqueous solubility, high photosensitivity, and high volatility restrict its application for the control of agricultural pests. Encapsulation can be an effective technique to overcome such hindrances. Therefore, P. pinnata oil (PO) was extracted from its seeds and analyzed for karanjin content (3.18%) by GC-MS/MS as the marker compound. Micro-encapsulation (MC) of PO was prepared by interfacial polymerization between isocyanates and polyamine and tested for insecticidal and larvicidal activities. Bioassay of the developed formulations was tested in-vitro against 2nd instar larvae of Bombyx mori (Bivoltine hybrid) and in-vivo insecticidal bio-efficacy was tested against aubergine aphid (Aphis gossypii G.) and whitefly (Bemisia tabaci G.). Various properties of micro-capsules viz., stability, size, oil content and release kinetics were examined. Average diameter of capsules (1 μm) with Zeta potential (-16 mV) was indicated by the Dynamic Light Scattering (DLS) instrument. Existence of PO in the microcapsules was confirmed by an optical microscopic study. Spectroscopic analysis revealed 87.4% of PO was encapsulated in polyurea shell. The shelf-life (T10), half-life (T50), and expiry-life (T90) of polyurea coated capsules were 11.4, 75.3 and 250.0 h, respectively. Polyurea coated PO capsule formulation showed evidence of in-vitro toxicity against 2nd instar larvae of B. mori (LC50= 1.1%; LC90 = 5.9%). The PO formulation also exhibited 67.0–71.8% and 62.4–74.8% control of aphid and whitefly population in aubergine at 4.0% dose following 7–14 days after application. The study unveiled its significance in developing controlled release herbal formulations of P. pinnata as an alternative to harmful conventional synthetic insecticides for crop protection.

Highlights

Indiscriminate use of synthetic pesticides in crop protection is a major concern for environmental pollution affecting air, water, soil, human and animal health (Foong et al, 2020)
We reported the preparation of emulsifiable concentrate (EC) formulation of pinnata oil (PO) with insecticidal properties (Purkait et al, 2019)
The present study aimed to develop polyurea coated encapsulated PO formulation; their characterization in terms of thermodynamic stability and release kinetics; and evaluation of insecticidal bio-efficacy

Summary

Introduction

Indiscriminate use of synthetic pesticides in crop protection is a major concern for environmental pollution affecting air, water, soil, human and animal health (Foong et al, 2020). Botanical pesticides can be promising alternatives to synthetic molecules, be cost-effective, IPM compatible and safe for the ecosystem and public health (Campos et al, 2018). Wall materials act as barriers to protect the core bioactive principles from degradation, evaporation and control diffusion to ensure sustained release (da Maciel et al, 2019). The usefulness of encapsulation technologies in botanicals in terms of increased solubility, protection against premature degradation, and sustained release of bioactive principles have been reported (Bilenler et al, 2015; Oliveira et al, 2018)

Methods

Results

Conclusion