Switchgrass (Panicum virgatum) is receiving significant attention as a feedstock for the production of liquid fuels such as ethanol.  In addition, switchgrass may also be a source of value-added products such as antioxidants, and our laboratory recently reported that switchgrass contains policosanols and á-tocopherol. Cave-in-Rock variety switchgrass was obtained from the September-October and the November-December harvests, ground to 4 mm mesh, and extracted with water at 50°C.  The extracts were freeze-dried and then dissolved in DMSO at concentrations ranging from 2.5-25 mg/ml.  The DMSO preparations were tested for Low Density Lipoprotein (LDL) oxidation inhibition activity using the Thiobarbituric Acid Reactive Substances (TBARS) assay.  TBARS results showed that the extracts inhibited LDL oxidation by as much as 37% in comparison to controls without extracts.  Experiments are underway to determine which compounds present in the extracts are responsible for the LDL oxidation inhibition activity. In addition to policosanols and á-tocopherol, the extracts most likely contain flavonoids, as peaks are detected at 360 nm, which is typical for flavonoids.  The liquid chromatography-mass spectrometry analysis of the switchgrass extract indicated the presence of m/z 303 and 449. By combining information on retention time with the mass spectrometry analysis, it can be inferred that switchgrass contains quercetrin.