Anti-Inflammatory Activity of Limonene in Prevention and Control of Injuries in the Respiratory System: A Systematic Review.

The pulmonary inflammatory response results of an injurious factor exposure and is associated with oxidative stress, which intensifies the pathological reaction. In this context, limonene, a monoterpene found in citrus fruits, can be a therapeutic alternative for treatment of this pathology, once it present known anti-inflammatory and antioxidant actions.The purpose of this article is to provide an overview on limonene anti-inflammatory activity and its capacity in preventing and controlling respiratory system injuries.A comprehensive literature search was performed on the Cochrane, Scopus, MEDLINE-PubMed, Web of Science and Lilacs databases using the keywords: "limonene", "lung", "pulmonary", "airway", "trachea", "lung injury", "respiratory system", "respiratory tract diseases".Studies on the use of limonene in disorders of the respiratory system, published until August 2019, were included. Excluding those who did not use limonene alone or treated lesions in different systems other than the respiratory system, without targeting its anti-inflammatory action. In addition, review articles, meta-analyzes, abstracts, conference papers, editorials/letters and case reports were also excluded.Of 561 articles found:64 in Cochrane, 235 in Scopus, 99 in Web of science, 150 in PubMed and 13 in Lilacs. After completing the systematic steps, 25 articles were selected for full reading and 7 papers remained in the review. An article was added after manual literature search, totaling 8 papers, with a high level of agreement on inclusion/exclusion among the researchers who examined the papers (Kappa index > 88%).Limonene has effective anti-inflammatory activity in both preventing and controlling respiratory system injuries.