This book consists of two parts. Part A describes the antioxidant activities of three different classes of natural products namely; Xanthones, Anthrones, and Acridones, and series of synthesized vanadium complexes. The structure-activity relationship studies on antioxidants have shown that certain functionalities or moieties play a major role in antioxidant potential. Part B of this book deals with effects of curcumin on obesity; in vitro and in vivo. It shows that dietary curcumin supplementation, through suppressing angiogenesis in adipose tissue, alter several key enzymes and transcription factors involved in energy and lipid metabolism and thus prevent obesity and associated metabolic complications.