Evaluation of Lavender, Peppermint, and Peony Oils in Reducing Cortisol-Mediated Inflammatory Responses in Brain Glial Cells
Yuna Jung
Branksomehall Asia, Jeju, Republic of Korea
Publication date: July 10, 2026
Branksomehall Asia, Jeju, Republic of Korea
Publication date: July 10, 2026
DOI: http://doi.org/10.34614/JIYRC2026I26
ABSTRACT
Aromatherapy is widely used for relaxation, but its direct biological effects on brain cells remain unclear because reported benefits may be influenced by placebo effects or other components of therapy, such as massage. This study investigated the effects of diphenhydramine and three fragrance-related oils, lavender, peppermint, and peony, on cytotoxicity and inflammation in A172 human glial cells. First, concentration screening was performed to identify treatment ranges that did not cause excessive baseline cytotoxicity. Diphenhydramine showed dose-dependent toxicity, with higher concentrations reducing cell viability, whereas lavender, peppermint, and peony maintained relatively stable viability up to 5 µL. A cortisol-induced inflammation model was then used to examine changes in the inflammatory markers TNF-α, IL-6, and IL-1β. Cortisol increased the expression of all three markers compared with the untreated control. Lavender, peppermint, and peony reduced cortisol-induced inflammatory marker expression, with peony showing the strongest anti-inflammatory effect. In contrast, diphenhydramine further increased inflammatory marker expression. These findings suggest that selected fragrance oils may help attenuate cortisol-mediated inflammation in glial cells, while diphenhydramine may exert a distinct pro-inflammatory effect under these experimental conditions.
Aromatherapy is widely used for relaxation, but its direct biological effects on brain cells remain unclear because reported benefits may be influenced by placebo effects or other components of therapy, such as massage. This study investigated the effects of diphenhydramine and three fragrance-related oils, lavender, peppermint, and peony, on cytotoxicity and inflammation in A172 human glial cells. First, concentration screening was performed to identify treatment ranges that did not cause excessive baseline cytotoxicity. Diphenhydramine showed dose-dependent toxicity, with higher concentrations reducing cell viability, whereas lavender, peppermint, and peony maintained relatively stable viability up to 5 µL. A cortisol-induced inflammation model was then used to examine changes in the inflammatory markers TNF-α, IL-6, and IL-1β. Cortisol increased the expression of all three markers compared with the untreated control. Lavender, peppermint, and peony reduced cortisol-induced inflammatory marker expression, with peony showing the strongest anti-inflammatory effect. In contrast, diphenhydramine further increased inflammatory marker expression. These findings suggest that selected fragrance oils may help attenuate cortisol-mediated inflammation in glial cells, while diphenhydramine may exert a distinct pro-inflammatory effect under these experimental conditions.
