A potential biopesticide fromAmorphophallus paeoniifoliousto increase the shelf life of stored food grains

Abstract

Food grain losses due to insect infestation during storage are serious problem. The bioactive flavonoids, extracted from elephant foot yam against α-amylase were isolated, lyophilized, characterized, and quantified. The acetone extract of elephant foot yam was found to have the highest flavonoid content of about 544.8 µg quercetin equivalent/g when compared to Methanol extract and Ethylacetate extract. Acetone extract also expressed lesser α-amylase activity (30.836IU), which signifies α-amylase inhibition. The HPLC analysis of acetone extract confirmed the presence of flavonoids (area = 98.34%). Flavonoid constituent, 9,12-Octadecadienoic acid is found to have highest peak in the GC-MS analysis of acetone extract. Whole wheat grains and moong dal were treated with acetone extract. Acetone extract of 0.25% concentration was found to be more efficient (100%) to repel S.oryzae and T.castaneum from wheat and moong dal significantly (p < .0001) within 48 hr and was confirmed by flour disc bioassay with FDI-90.47% within 24 hr for acetone extract. Practical applications Extension of shelf life period of the stored food grains during postharvest and storage period is a challenging task. The use of chemical pesticides for the control of crop pests is increasingly in question due to their detrimental side effects on humans and environment. So, the need for pesticides from biological origin is very important to control the food grain pest during storage and postharvest period. Raw material used in this study (elephant foot yam) is cheap and available throughout the year. The assays confirmed that the extract will be a promising biopesticide against insects that infest stored food grains such as Sitophilus oryzae and Tribolium castaneum, thereby increasing the shelf life of the stored food grains and restoring the nutritional value of grains. The important stakeholders to be benefitted are Agriculturalists, Government agencies, and private sectors involved in storage of grains and Common man/Society at large.