Poster Presenter

Screening Rhei Rhizome Potency Using Individual Component And Whole Extract Approaches Of Chemical Mixture Analysis
Zeyad Ibrahim Alehaideb, Zeyad Alehaideb, Kimberly Chin, Mei Cun Yao, and Francis CP Law
Canada

Rhei Rhizoma (RR) is a widely prescribed herb in traditional Chinese medicine. The potency of a RR ethanolic extract was studied using the individual component (IC) and whole extract (WE) approaches of assessing the effects of chemical mixtures: (a) IC approach. The RR extract was analyzed by HPLC and found to contain the following bioactive chemicals: rhein (0.12 mg/ml), emodin (0.24 mg/ml), and aloe-emodin (AE, 0.09 mg/ml). The IC50s of rhein, emodin, and AE inhibition on in vitro hepatic microsomal erythromycin demethylase (ED) activity were 0.0068 µM, 0.0023 µM, and 0.00085 µM, respectively. The RR potency was calculated to be 0.088 mg AE equivalents/ml. (b) WE approach. RR potency also was estimated based on in vitro inhibition of liver microsomal ED by the whole extract; it was found to be 0.972 mg AE equivalents/ml. The lower AE equivalents of the IC approach probably is explainable by the fact that not all bioactives have been identified in RR. Results of our study show that RR potency is best determined using the WE approach. This innovative application of hepatic CYP-450 enzymes inhibition provides a rapid and cost-effective method of screening large numbers of botanical drugs for their potencies.