Abstract: To investigate the chemical constituents and their insecticidal activities from the leaves of Callistemon viminalis. The constituents were isolated and purified by silica gel column chromatography,Sephadex LH-20 column chromatography as well as C₁₈ reversed phase column chromatography.Their structures were elucidated by spectroscopic methods.The insecticidal activity of isolated compounds was evaluated by stomach toxicity method.Thirteen compounds were isolated from ethyl acetate fraction of volume fraction 95% ethanolic extract from the leaves of Callistemon viminalis. Their structures were identified as 3,3′,4′-tri-O-methylellagic acid (1),quercetin (2),sideroxylin (3),kaempferol (4),5-hydroxy-7,4′-dimethoxy-6-methylflavone (5),farrerol (6),methyl gallate (7),protocatechuic acid (8),gallic acid (9),2,6-dihydroxy-4-methoxyisovalerophenone (10),vimifoliol (11),succinic acid (12) and betulinic acid (13).Compounds 1-9、11、12 were isolated from this plant for the first time.Compound 10 was showed potent insecticidal activity against Spodoptera exigua.

Key words: Callistemon viminalis, chemical constituents, structural identification, Spodoptera exigua