Topical Application of <i>Citrus limon</i> Peel Essential Oil Increased Pro-Inflammatory Cytokines Expression on Type IV Hypersensitivity Reaction

Introduction: Citrus limon peels essential oil has the potential to be developed as a topical medicine due to its active components. The essential oil has been demonstrated in numerous studies to have anti-inflammatory, anti-microbial, antifungal, and antioxidant properties. A study is required to determine whether Citrus limon peel essential oil can cause a type IV hypersensitivity reaction by examining the expression of the cytokines TNF-, IL-1, and IL-6 as well as the clinical manifestations on an animal skin. In this study, the effect of topically applying the essential oil of Citrus limon peel on the expression of TNF-α, IL-1, and IL-6 as well as on type IV hypersensitivity reaction symptoms was examined. Methods: This study is based on the guinea-pig maximisation test method in NADFC RI Regulation Number 7 of 2014, with two groups (control group and treatment group) for each set of ten samples. Citrus limon peels essential oil was administered to the treatment group, whereas CMC-Na was given to the control group. Animal models were euthanized after which the tissues were prepared as specimens for immunohistochemical staining. The expression of cytokines was computed and examined using a light microscope. Results: There were no clinical signs of type IV hypersensitivity in either group, and the expression of TNF-α, IL-1 and IL-6 in the treatment group was found higher than in the control group. Conclusion: After topical administration of Citrus limon peels essential oil, there was an increase in the expression of TNF-α, IL-1 and IL-6 without any clinical symptoms of type IV hypersensitivity.