Inhibitory effects and chemical basis of Eucalyptus orelliana wood meals on the growth of Alexandrium tamarense
桉木粉对塔玛亚历山大藻（Alexandrium tamarense）的抑制作用及其化学基础研究

Abstract: To provide information on the screen of newly and efficient algaecides in controlling harmful algal blooms (HABs), the effects of wood meals from Eucalyptus torelliana, Eucalyptus urophylla, Eucalyptus exserta on the growth of Alexandrium tamarense were observed and the chemical basis of the antialgal effect was discussed. The results show that the inhibitory activities of the three wood meals are different, of which, E. torellianar wood meals have the highest inhibitory activity. There are little differences in antialgal action between asepsis and rude wood meals, suggesting that some antialgal compounds from wood meals may be responsible for the inhibition and that microorganisms from wood meals have little effect on the inhibition. The acetone-water extract from E. torellianar wood meals is shown to have stranger inhibition on A. tamarense than ethyl acetate, water and methanol extracts. The acetone-water extract from E. torellianar wood meals was further divided into extract A, B, C and D and the inhibitory activities were compared. The extract D is shown to have highest inhibitory activity. 3 mg/L of the extract apperars 81% inhibition rate to A. tamarense in the 3nd day. GC-MS show that extract D contains mostly ketones such as 2-cyclohexen-1-one,4-hydroxy-3,5,6-trimethethy-4-3(3- -oxo-1-butenyl)]-forinula and 2(4H)-Benzofuranone,5,6,7,7a-tetrahydro- 4,4,7a-trimethyl-(R)-Formula]. These results suggest that wood meals from E. torelliana had certain inhibitory effect on A. tamarense, and that ketones may be responsible for the inhibition.