Two novel glycosides from the fruits of Morinda citrifolia (noni) inhibit AP-1 transactivation and cell transformation in the mouse epidermal JB6 cell line

The fruit juice of Morinda citrifolia (noni), a plant originally grown in t he Hawaiian and Tahitian islands, has long been used by islanders to treat diseases, including cancer. Two novel glycosides, 6-O-(beta -D-glucopyranos yl)-1-O-octanoyl-beta -D-glucopyranose and asperulosidic acid, extracted fr om the juice of noni fruits, were used to examine their effects on 12-O-ted tradecanoylphorbol-13-acetate (TPA)- and epidermal growth factor (EGF)-indu ced AP-1 transactivation and cell transformation in mouse epidermal JB6 cel ls. The results indicated that both compounds were effective in suppressing TPA- or EGF-induced cell transformation and associated AP-1 activity. TPA- or EGF-induced phosphorylation of c-Jun, but not extracellular signal-regu lated kinases or p38 kinases, was also blocked by the compounds, indicating that c-Jun N-terminal kinases were critical in mediating TPA- or EGF-induc ed AP-1 activity and subsequent cell transformation in JB6 cells.