arachidonate 5-lipoxygenase inhibitor arachidonate 5-lipoxygenase inhibitor arachidonate 5-lipoxygenase inhibitors are compounds that slow or stop the action of the arachidonate 5-lipoxygenase (5-lipoxygenase or 5-lox) enzyme, which is responsible for the production of inflammatory leukotrienes. the overproduction of leukotrienes is a major cause of inflammation in asthma, allergic rhinitis, and osteoarthritis. examples of 5-lox inhibitors include the pharmaceutical drugs meclofenamate sodium, zileuton and the natural products myxochelins/pseudochelin as well as nordihydroguaiaretic acid (ndga). some chemicals found in trace amounts in food, as well as some dietary supplements, have been shown to inhibit 5-lox; these include baicalein, caffeic acid, curcumin, hyperforin and st john's wort. acetyl-keto-beta-boswellic acid (akba), one of the bioactive boswellic acids found in boswellia serrata (indian frankincense) has been found to inhibit 5-lipoxygenase strongly as an allosteric inhibitor. boswellia administration has been shown to reduce brain edema in patients irradiated for brain tumor and it's believed to be due to 5-lipoxygenase inhibition.