Cancer is the second leading cause of death across the globe. Because of the toxic side effects of chemotherapy, scientists are interested in chemoprevention. One cause of cancer is from our body’s ability to convert polyaromatic hydrocarbons (PAHs) found in our diet to even more carcinogenic compounds by Cytochrome P450 1A1 and 1B1 (CYP1A1 and CYP1B1). Because Chinese herbs have been used in Eastern medicine for chemoprevention and cancer treatments, we tested several extracts for their ability to inhibit these enzymes at 10 µg/mL using ethoxyresorufin as a substrate. Enzyme activity was determined by exciting the reaction mixture at 574 nm and measuring the fluorescence at 585 nm. The percentage of activity that remains after adding the extracts was assessed and those that had low percentage of activity after adding the inhibitor displayed the highest inhibition. The dichloromethane extract from the Bamboo herb resulted in 8.53% of the uninhibited CYP 1A1 activity and 2.83% for the uninhibited CYP 1B1 activity. Acetonitrile extract from the Bamboo herb displayed 14.17% for 1A1 and 14.96% for 1B1. Dimethylformamide (DMF) extract from the Dendrobium nobile herb resulted in 29.45% for 1A1 and 17.80% for 1B1. Ethanol extract from Bamboo herb resulted in 29.50% for 1A1, 9% for 1B1 and at a concentration of 5 µg/mL displayed 63.31% for 1A1 and 31.76% for 1B1. Albizia julibrissium was the only extract that had the highest remaining activity (lowest inhibition) at 81.24% for 1A1 and 58.58% for the 1B1. The extracts that inhibited the enzymes to less than 80% of the uninhibited activity are currently being assayed to determine their IC<sub>50 </sub>value. Further analysis such as, individual screening, is also being done on several other extracts.

Chinese herb extracts may exert chemopreventitve effects through inhibitiion of cytochrome P450 1A1 and 1B1

2019 Spring National Meeting

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