Arctiin

Arctiin induces growth inhibition and dephosphorylates the tumor-suppressor retinoblastoma protein in human immortalized keratinocyte HaCaT cells. The growth inhibition caused by arctiin is associated with the downregulation of cyclin D1 protein expression. The arctiin-induced suppression of cyclin D1 protein expression occurs in various types of human tumor cells, including osteosarcoma, lung, colorectal, cervical and breast cancer, melanoma, transformed renal cells and prostate cancer^[1].

HaCaT cells are plated at 1×10⁵ cells in 25-mm-diameter dishes. Twenty-four hours after plating, various concentrations of arctiin are added to the culture medium. From the first to the third day after plating, the number of viable cells is counted by the trypan blue dye exclusion test.

Arctiin has anti-cancer properties in animal models. arctiin has a remarkable anti-tumor-promoting effect as seen in a two-stage carcinogenesis test of mouse skin tumors induced by 7,12-dimethylbenz[α]anthracene as an initiator and 12-Otetradecanoyl phorbol-13-acetate (TPA) as a promoter by topical and oral administration. It also has a protective effect on 2-amino-1-methyl-6- phenylimidazo[4,5-β]pyridine (PhIP)-induced carcinogenesis particularly in the mammary gland during the promotion period^[1]. Arctiin is orally effective against either IFV-inoculated normal or 5-fluorouracil (5-FU)-treated mice^[3].