Oxidative stress is caused by an imbalance in the production of reactive oxygen species (ROS) and antioxidant defenses. The development of pulmonary hypertension (PH) is one disease that can be attributed to oxidative stress, and studies have shown antioxidants as potential therapeutics. Peptides extracted from botanical sources are widely used for this purpose and have been shown to have bioactive properties such as antimicrobial, anticancer, antihypertensive and antioxidant properties, which are well suited for pharmaceutical development. Using bioassay-guided isolation methods, this study identified bioactive peptide candidates, isolated from our botanical library, for the development of improved antioxidant treatment for PH. Total protein of more than 300 botanicals was extracted and analyzed via polyacrylamide gel electrophoresis. Antioxidant capacity of botanical peptides was analyzed using the Oxiselect Total Antioxidant Capacity (TAC) assay (Cell Biolabs) and the SOD activity assay (Dojindo Molecular Tech). The initial screens of protein extracts identified at least three botanical sources (BOT0123, BOT0044, and BOT0353) with up to 2557 μM copper reducing equivalents (CRE). The EC50 of the uric acid positive control was 1.093 μM CRE. Our preliminary results have identified botanical protein extracts with antioxidant bioactivity that will be used in further bioassay-guided isolation and identification of specific peptides. Future studies will focus on defining effective concentrations (EC50 and ECmax) in vitro, testing candidate antioxidant peptides in cell culture and in animal models.
Thao Luu, ’16
Ho Chi Minh City, Vietnam
Sponsor: Cynthia Strong
Additional Authors: Juan M. Martinez, Ji Hye Chun, Leah Villegas, MyPhuong Le