Bio‐Insecticidal Efficacy of Phytochemicals in Acorus calamus Rhizome and Piper longum Plant Extracts as Green Alternatives to Synthetic Insecticides Agains

ABSTRACT

To meet the increasing food demands of a growing global population, agricultural productivity must rise substantially. However, the excessive reliance on synthetic pesticides has resulted in the development of resistance among stored‐product insect pests, necessitating the search for sustainable and eco‐friendly alternatives. The present study evaluates the bioactive potential of extracts obtained from the rhizomes of Acorus calamus Linn and the fruits of Piper longum Linn against Tribolium castaneum Herbst. The investigation focused on the insecticidal, phenolic, flavonoid and antioxidant properties of the extracts, along with the identification of the bioactive compounds responsible for these activities. A. calamus exhibited the highest repellency (98.3%) and induced complete mortality within 9 days at a concentration of 100 mg/mL, with Lethal Time 50 (LT ₅₀ ) and Lethal Time 90 (LT ₉₀ ) of 5.34 and 7.70 days, respectively. In contrast, P. longum demonstrated 92.1% repellency but did not exhibit significant contact toxicity. Gas chromatograph–mass spectrometry profiling revealed asarone (88.2%) as the predominant bioactive constituent in A. calamus , whereas piperine (39.5%) was identified as the major compound in P. longum , both of which are likely responsible for the observed insecticidal activity. Furthermore, both extracts displayed strong antioxidant potential, with P. longum showing higher total phenolic content (10.45 mg GAE/g) and total flavonoid content (9.17 mg QE/g) compared to A. calamus . Overall, the findings suggest that extracts of A. calamus rhizomes and P. longum fruits possess significant potential as sustainable plant‐derived protectants for stored commodities, providing an environmentally friendly alternative to conventional synthetic insecticides.