Dendrobium Nobile Stem Extracts May Prevent Cancer by Inhibiting Cytochrome P450 1A1 and 1B1

Traditional Chinese medicine has used herbs for many centuries to treat a variety of ailments including cancer. Discovering the active components in many of these herbs has been a line of research for a number of scientific investigations. Two compounds extracted from dendrobium nobile stems have previously demonstrated anticancer activity by inducing apoptosis in various cancer cell lines. We have found that extracts from the stem of dendrobium nobile inhibit cytochrome P450 1A1 and 1B1. Dendrobium nobile stems extracted in dimethylsulfoxide, dimethylformamide, or ethanol inhibited cytochrome P450 1A1 and 1B1 to less than 50% of their uninhibited activity. Specifically, the ethanol extracts provided the greatest inhibitory effects with an IC50 of 0.63 μM with respect to cytochrome P450 1A1 and an IC50 of 1.4 μM with respect to cytochrome P450 1B1. These results suggest that these extracts contain compounds that could prevent or treat cancer by a different mechanism from ones previously discovered and could lead to the identification of new chemopreventive compounds from the stems of dendrobium nobile.