Chemical composition and biological activity of star anise Illicium verum extracts against maize weevil, Sitophilus zeamais adults.

Linlin Wei,Yanzhang Huang,Zonghai Shen,Rimao Hua,Maoye Li,Yujie He,Shiguang Li

doi:10.1093/jis/14.1.80

Abstract

This study aims to develop eco-friendly botanical pesticides. Dried fruits of star anise ( Illicium verum Hook.f. (Austrobaileyales: Schisandraceae)) were extracted with methyl alcohol (MA), ethyl acetate (EA), and petroleum ether (PE) at 25°C. The constituents were determined by gas chromatography-mass spectrometry, and the repellency and contact toxicity of the extracts against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) adults were tested. Forty-four compounds, whose concentrations were more than 0.2%, were separated and identified from the MA, EA, and PE extracts. The extraction yields of trans-anethole, the most abundant biologically active compound in I. verum , were 9.7%, 7.5%, and 10.1% in the MA, EA, and PE extracts, respectively. Repellency increased with increasing extract dose. The average repellency rate of the extracts against S. zeamais adults peaked at 125.79 µg/cm 2 72 hr after treatment. The percentage repellency of the EA extract reached 76.9%, making it a class IV repellent. Contact toxicity assays showed average mortalities of 85.4% (MA), 94.5% (EA), and 91.1% (PE). The EA extract had the lowest median lethal dose, at 21.2 µg/cm 2 72 hr after treatment. The results suggest that I. verum fruit extracts and trans-anethole can potentially be developed as a grain protectant to control stored-product insect pests. Other active constituents in the EA extract merit further research.

Highlights

Sitophilus zeamais Motschulsky (Coleoptera, Curculionidae) is one of the major pests of stored products
In the current study, according to the extraction yields, yields of trans-anethole from I. verum in methyl alcohol (MA), ethyl acetate (EA), and petroleum ether (PE) solvents were 9.7%, 7.5%, and 10.1%, respectively, which are higher than those obtained by hydrodistillation
The extracts obtained from MA contained more high-polar materials, whereas the extracts obtained from PE

Summary

Introduction

Sitophilus zeamais Motschulsky (Coleoptera, Curculionidae) is one of the major pests of stored products It infests rice, wheat, corn, lotus seed, Rhizoma gastrodiae, and Chinese herbs, causing heavy losses of both quantity and quality of stored products worldwide. Wheat, corn, lotus seed, Rhizoma gastrodiae, and Chinese herbs, causing heavy losses of both quantity and quality of stored products worldwide It attacks intact grains and is quite destructive, as its larvae and adults feed and develop inside the kernel (Lopez et al 2008; Ojo and Omoloye 2012). The long repeated use of synthetic pesticides has led many insect pests, including S. zeamais, to develop pesticide resistance (Isman 2006) and pest resurgence This phenomenon contributes to the vicious cycle of increasing doses, increasing application costs, and enhancing resistance. Investigating and using effective low- to nontoxic alternatives to synthetic pesticides to control stored-product pests is essential in ensuring food safety and human health

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