Prior to this, he was the Assistant Director of the Center for Human Nutrition in the Department of Medicine, University of California, Los Angeles (UCLA), and an Assistant Adjunct Professor in the David Geffen School of Medicine at UCLA. His research group, the Bioactive Botanical Research Laboratory, investigates medicinal plants, including plant foods, as potential sources of botanical drugs, phytopharmaceuticals and phytomedicines. Targeted diseases of interest include cancer, diabetes and inflammation.