Phytochemical profiling by GC-MS, in vivo toxicity bioassay, and insecticidal evaluation of Pluchea carolinensis (Jacq.) Don leaf extracts from Puerto Rico

Medicinal plants are known to produce and synthesize biologically active secondary metabolites that can be derived as natural product formulations for many applications including their potential pharmaceutical use. Leaf extracts from Pluchea carolinensis (Jacq.) Don (Asteraceae), a traditional medicinal plant of the Caribbean region, were obtained by micro-Soxhlet extraction using organic solvents of different polarities, and their phytochemical composition was identified using Gas Chromatography-Mass Spectrometry (GC-MS). These extracts were mostly composed of sesquiterpenes and sesquiterpenoids, triterpenoids, phenols, and other bioactive phytochemicals. Squalene, α-tocopherol, and β-amyrin acetate were phytocompounds identified in these leaf extracts recognized to have hypolipidemic, antiviral, and antidiabetic properties. The toxicity or preliminary cytotoxic activity of Pluchea carolinensis leaf extracts was assessed in vivo using the brine shrimp lethality bioassay, where the chloroform extract (PCC) resulted toxic to Artemia franciscana, with an LC₅₀ value of 375.29 μg/mL. The insecticidal activity of P. carolinensis leaf extracts against an insect of agricultural significance was also explored for the first time through contact toxicity bioassays with Ferrisia sp. (Hemiptera: Pseudococcidae). Results revealed a low insecticidal activity of these leaf extracts against this pest, with the methanolic extract (PCM) having the best effect (LC₅₀ = 16.11 mg/mL after 24 h). The findings of this study underline the importance of further pharmacological research to evaluate the anti-inflammatory, antibacterial, anticancer, or antioxidant potential of the bioactive secondary metabolites in the chloroform extract of Pluchea carolinensis leaves.