Chem. Pharm. Bull. 55(4) 675—678 (2007)

monly called grass trees, is an Australian native plant genus. A commercially available resin commonly obtained from Xanthorrhoea trees is gum accoroides, but no medical uses have been described for this plant. In our continuing search for allergy-preventive substances from natural sources we found that extracts of X. hastilis exhibited allergy-preventive activity. Known extracts from X. hastilis include benzoic acid, fragrant oil and C-methylated flavonoid, but no detailed chemical study had been reported. In the present study, we isolated from X. hastilis, a new flavanone, 3 ,5 -dihydroxy-7,4 -dimethoxyflavanone (1) and two new chalcones, 3,5,2 -trihydroxy-4,4 -dimethoxychalcone (2) and 5,2 -dihydroxy-3,4,4 -trimethoxychalcone (3). We report their structures and also the isolation of five known compounds. Finally, we describe the allergy-preventive effects of these compounds isolated from X. hastilis.