GC-MS based phytoconstituents profiling, toxicity assessment, and potential of Genipa americana L. leaf extracts as natural insecticides against striped mealybugs Ferrisia sp.

Abstract

Plant-based botanical insecticides are emerging as a promising solution for crop protection while minimizing concerns related to environmental pollution and insect resistance due to their natural origin. Leaf extracts from the folkloric medicinal plant Genipa americana L. (Rubiaceae) were obtained through micro-Soxhlet extraction and subjected to Gas Chromatography-Mass Spectrometry (GC-MS) analysis to identify their phytochemical constituents. GC-MS profiling revealed that these extracts were mainly composed of carboxylic acids, esters, steroids, phenols, triterpenes, and other bioactive secondary metabolites. Phytocompounds with different biological activities such as di-isobutyl phthalate, hexadecanoic acid, linoleic acid, squalene, α-tocopherol, and stigmasterol were identified. Toxicity assessment through brine shrimp lethality tests proved the potential pesticidal activity of two of these extracts. The chloroform extract (GAC) was the most toxic against Artemia salina with an LC₅₀ value of 92.85 μg/mL followed by the dichloromethane extract (GAD), which also resulted toxic but less than the positive control, with an LC₅₀ of 485.46 μg/mL. Contact toxicity bioassays with Genipa leaf extracts against the striped mealybugs Ferrisia sp. (Hemiptera: Pseudococcidae) demonstrated that the GAC extract has the maximum insecticidal response, with an LC₅₀ of 7.89 mg/mL, followed by GAD extract, with an LC₅₀ of 16.42 mg/mL. This is the first study in which Genipa americana leaf extracts are assessed for their insecticidal activity against striped mealybug insects spotlighting the potential of both GAC and GAD leaf extracts as natural insecticides against this pest of negative economic impact on agriculture.