研究指出1, 8- cineole 為一種單萜類物質，廣泛存在於桉樹屬(Eucalyptus)植物的葉片中，為目前最具剋他潛力的化合物之一。透過不同敏感植物材料進行生物檢定(bioassay)之分析結果，發現剋他物質1, 8-cineole 可抑制萵苣、油菜和菸草種子的發芽和胚根與胚軸的生長，其中尤其胚根對於1, 8-cineole 最為敏感。試驗結果顯示1, 8-cineole 嚴重抑制有絲分裂各時期之發育，尤其以前期為劇。利用顯微鏡觀察根尖細胞染色體結果發現，1, 8-cineole 會抑制根尖細胞的有絲分裂進行，是在分裂前期階段抑制細胞週期。此外，其亦能大幅降低油菜根尖細胞核與質體內DNA 的合成。

1, 8- Cineole, one of the monoterpene compounds, has been found it widely exists in leaves of Eucalyptus plants, with a strong allelopathic potential. Bioassay using several sensitive plant species as materials showed that seed germination, hypocotyl and radicle elongation of three plants including lettuce, rape and tobacco were inhibited by 1,8-cineole, and radicle organ showed the highest sensitivity. Experimental results also showed that various developmental stages of mitosis were retarded seriously by 1,8-cineole, especially the early stage. Microscopic observation of chromosome in root tip cells confirmed that the mitosis was inhibited at the early division stage, and both DNA systhesis in nucleus and plastids were largely decreased.