LSF, a chiral metabolite of pentoxifylline, acts as a potent anti-inflammatory agent. (R)-LSF is the biologically active isomer of LSF. It is a potent inhibitor of the generation of phosphatidic acid (IC50 = 0.6 µM) from cytokine-activated lysophosphatidic acyl transferase (LPAAT), which has been shown to protect mice from endotoxic shock. (R)-LSF suppresses the production of the proinflammatory cytokine IFN-γ, inhibits interleukin 12-mediated STAT-4 activation, and enhances glucose-stimulated β-cell insulin secretion, reducing the onset of diabetes in a non-obese diabetic murine model.