Prostaglandins and leukotrienes derive enzymatically from the Arachidonic acid cascade. Cyclooxygenase (Cox-1 or -2) pathways produce prostaglandins, while lipooxygenase pathways synthesize leukotrienes. PGE synthase converts prostaglandin (PG) H2 into PGE2, which is involved in several pathologies such as periodontal disease and promoting tumor cell survival. 5-lipoxygenase catalyses the conversion of Arachidonic acid into 5-HPETE (5-hydroperoxyeicosatetraenoic acid) and then into LTA4. While the addition of glutathione to LTA4 produces LTC4, LTA4-hydrolase converts LTA4 into LTB4. Leukotrienes are very important agents in inflammation pathways, and are involved in asthmatic and allergic reactions.