15-Lipoxygenase Inhibitor I is a heterocyclic pyrimidobenzothiazine compound which inhibits 15-LO with an IC50 value of 18 μM. Studies indicate that 15-Lipoxygenase has biological significance as a mediator of inflammation, thrombosis, and cancer via the oxidation products of the enzyme. It is believed that 15-Lipoxygenase Inhibitor I functions as an inhibitor by interfering with the redox cycle of 15-Lipoxygenase. Furthermore, 15-Lipoxygenase Inhibitor I acts as a catalyzing agent in the oxidation of polyunsaturated fatty acids.