Objective   To study the effects of chlorophyllin on proliferation and cell cycle in vit ro in human bronchial epithelial cell line(16 HBE)transformed by trans-benzo(a)pyrene-trans-7, 8-dihydrodiol-9, 10-epoxide(trans-BPDE).

  Methods   MTTmethod and flow cytometry were used to investigate alteration of the growth curve and cell cycle among untreated control cells, malignant transformed cells induced by trans-BPDE and the anti-transformed cells treated with chlorophyllin and to analyse effects of chloropyllin on the cells.

  Results   Compared with that of control 16 HBE, the vitality of malignant transformed cells was higherand it was inhibited significantly in the anti-transformed cells treated with 100μmol/L chloropyllin.However it was uninhibited in the cells treated with only chloropyllin of the same concentration.The proportion of G₀/G₁ cells decreased significantly after beingtansformed by trans-BPDE while the proportion increased after being anti-transformed by chlorophyllin.Meanwhile, no change was observed in G₀/G₁ phase of cells treated with the same concentration of chlorophyllin.

  Conclusion   Acertain concentration of chlorophyllin may have significant anti-profileration activity in human bronchial epithelial cell line 16 HBE.It interfere cell cycle course by enhancingthe G₀/G₁ phase proportion in malignant transformed cell and result in change of cell profileration and differentiation.