Larvicide potential and toxicity of extract and fractions from flowers of Tecoma stans (Bignoniaceae)

The extract and fractions from flowers of Tecoma stans (Bignoniaceae), an invasive plant in Brazil, were evaluated for their larvicidal potential against Culex quinquesfasciatus larvae and for the toxicity to Artemia salina. The hexane (HEX) fraction caused 100% mortality at 1000 µg mL^-1 in the first 24 h of exposure (LC₅₀ = 118.73 µg mL^-1 and LC₉₀ = 306.06 µg mL^-1). The LC₅₀ and LC₉₀ values for the dichloromethane (DCM) fraction were 399.40 µg mL^-1 and 853.36 µg mL^-1. Only the ethyl acetate (EA) fraction was toxic to A. salina. The results suggest selectivity from the HEX and DCM fractions of T. stans against C. quinquefasciatus and may serve as eco-friendly alternatives to synthetic larvicides.