The Cytotoxic Effect of Genistein, a Soybean Isoflavone, against Cultured Tribolium Cells.

Shingo Kikuta

doi:10.3390/insects11040241

Abstract

The red flour beetle Tribolium castaneum is a known pest of various grains and stored-products such as wheat flours; however, T. castaneum feeds on and infests soybean and soy products. For more than 60 years, soy flour has been suggested to be unstable food for Tribolium spp. because it causes larval development failure. However, it remains unknown whether soy flour affects adult beetles. The objective of the present study was to examine the effects of soy flour and its related isoflavones against T. castaneum using an artificial dietary intake assay. Beetles were fed gypsum (a non-digestible compound) mixed with either water (control) or soy flour. Significantly fewer beetles survived after being fed the soy flour treatment. Although the soy isoflavone genistein, a defensive agent and secondary metabolite, decreased the T. castaneum adult survival, it required a long time to have a lethal effect. Therefore, the cytotoxic effects of soy flour, i.e., the rapid biological responses following isoflavone addition, were also examined using a cultured cell line derived from T. castaneum. Both genistin and genistein significantly affected the survival of the cultured cells, although genistein had a stronger lethal effect. This study demonstrated the toxicity of genistein found in soybean against T. castaneum cultured cells within 24 h period. Genistein may be used as an oral toxin biopesticide against T. castaneum.

Highlights

The red flour beetle Tribolium castaneum (Herbst) is a serious stored-grain pest that attacks various foods, such as wheat flour, dried fruits, nuts, pasta, cereal germs, and processed foods [1,2].The dietary intake of adult T. castaneum beetles is activated by carbohydrates, such as fructose, sucrose, and mannitol [3]
The present study examined the insecticidal effects of flavonoids that occur naturally in plants as candidate toxic insecticides against T. castaneum
These findings indicated that T. castaneum adult beetles recognized and digested gypsum-containing soy flour

Summary

Introduction

The red flour beetle Tribolium castaneum (Herbst) is a serious stored-grain pest that attacks various foods, such as wheat flour, dried fruits, nuts, pasta, cereal germs, and processed foods [1,2].The dietary intake of adult T. castaneum beetles is activated by carbohydrates, such as fructose, sucrose, and mannitol [3]. Tribolium confusum (Jacquelin du Val), a beetle species that is very similar in appearance to T. castaneum, attacks and infests peas as well as stored-grains and associated products; it has rarely been identified as a pest of soybean and soy products [4]. In previous studies, both the larvae of. T. confusum and T. castaneum did not develop to pupal and adult stages when fed on soy flour, resulting in a decreased number of larval instars in their development [5,6].

Objectives

Methods

Discussion

Conclusion