Potential larvicidal effects and phytochemical composition of medicinal plant extracts from Barringtonia asiatica and Xylocarpus granatum against Aedes aegypti, the dengue vector (Diptera: Culicidae)

Dengue is endemic in Thailand, with periodic increases in incidence reported across all regions of the country. Aedes aegypti (Linnaeus, 1762) is the principal vector of dengue virus and remains a major target for disease control. This study investigated the phytochemical composition and larvicidal activity of leaf, stem, and fruit extracts of two medicinal plants, Barringtonia asiatica and Xylocarpus granatum, collected in Thailand. Aqueous, ethanol, and hexane solvents were used for extraction. Gas chromatography-mass spectrometry (GC-MS) analysis detected 107 chromatographic peaks in B. asiatica extracts and 132 in X. granatum extracts, including both tentatively identified and unidentified constituents. Chemical group profiles differed markedly among extracts, with compounds classified as “others” predominating in several aqueous extracts, whereas sterols/triterpenoids and hydrocarbons were abundant in several organic extracts. Larvicidal activity against Ae. aegypti larvae varied according to plant species, plant part, solvent type, concentration, and exposure time. Larval mortality generally increased with increasing extract concentration and longer exposure time in the active extracts. Among all tested extracts, the hexane fruit extract of X. granatum showed the greatest relative larvicidal potency, with LC₅₀ values of 570 ppm at 24 h and 313 ppm at 48 h. The aqueous fruit extract and hexane stem extract of B. asiatica also showed considerable activity after 48 h of exposure, with LC₅₀ values of 713 ppm and 858 ppm, respectively. These findings suggest that selected plant parts of B. asiatica and X. granatum, extracted with appropriate solvents, may serve as potential sources of bioactive compounds for developing botanical larvicidal products against Ae. aegypti.