The Study of Tamanu (Calophyllum inophyllum) OIL Effects on AtopicDermatitis-Related GENE Expression Levels on TNF-α and IFN-γ Incuced HaCaT Cells

Abstract

Atopic dermatitis (AD) is a common chronic inflammatory skin disease affecting almost 2.4% of the population worldwide. Due to the complex interactions of genetic, environmental, and immunological variables, AD is still incurable as the knowledge of this complex disease is still limited. Moreover, current available treatments can only treat its symptoms and stop them from getting worse. The most widely used treatment for AD consists of applying steroid creams on the affected skin area. Prolonged use of these steroid creams carries the risks of side effects. The limited availability of safe and affordable treatments for AD makes the development of new alternative treatments for AD both crucial and urgent. Tamanu oil, which is extracted from Calophyllum inophyllum nuts, has been demonstrated to have anti-inflammatory and wound-healing properties. These properties make tamanu oil an ideal candidate for a natural active ingredient for treating AD as both inflammation and damaged skin barrier functions are hallmark conditions that characterize AD. In this study, HaCaT cells induced with TNF-α and IFN-γ were utilized as AD models for investigating the effects of tamanu oil on the gene expression of AD-related genes: CTACK, IL-25, IL-33, MDC, TARC, and TSLP that are related to inflammation and skin barrier genes FLG and IVL. The investigation revealed that treatments with 5 µg/mL pure tamanu oil were able to restore the expression of IL-33 gene back to normal upon TNF-α and IFN-γ induction. In contrast, 10 µg/mL was recommended for MDC, TSLP, and FLG, making these treatments the most potent concentrations to be used as AD alternative treatment candidates in further studies. However, phytochemical screening should be performed in the future to identify the specific bioactive compound responsible for tamanu oil’s anti-inflammatory and wound-healing properties.