Antimalarial compounds isolated from Koelreuteria paniculata growing in Egypt

Bioassay-guided fractionation of the 70% ethanolic extract of Koelreuteria paniculata (Sapindaceae) growing in Egypt, resulted in the isolation of eleven compounds (1 – 11). The structures of the isolated compounds were elucidated by using 1D and 2D NMR spectroscopy as well as HR-ESI-MS. The isolated compounds were evaluated for their antimalarial, antileishmanial, antifungal and antimicrobial activities. The isolated compounds were identified as: methyl-myo-inositol (1), loliloide (2), gallic acid (3), methyl gallate (4), ethyl gallate (5), palmitic acid monoglyceride (6), 5-methoxy luteolin (7), kaempferol-7-rhamnoside (8), kaempferol-3-rhamnoside (9), β-sitosterol (10), and β-sitosterol-glucoside (11). Compound 1 was isolated for the first time from this genus, while compounds 2, 7 and 8 were isolated for the first time from the Sapindaceae family. Compounds 4 and 5 showed the same antimalarial activity against chloroquine-sensitive (D6) Plasmodium falciparum protozoan with an IC₅₀ of 1.28 µg/mL, and against chloroquine-resistant (W2) P. falciparum protozoan with an IC₅₀ value of 1.85 and 0.77 µg/mL, respectively. Compound 5 showed antibacterial activity against Escherichia coli with an IC₅₀ value of 20 µg/mL.