Anti-Inflammatory Effects of <i>Ajuga decumbens</i> Extract under Blue Light Stimulation

We investigated the potential of <i>Ajuga decumbens</i> Thunb. as an anti-inflammatory agent by utilizing plant resources to develop materials through the application of tissue culture and light-emitting diode (LED) cultivation technologies. To compare the changes between <i>A. decumbens</i> callus extract (ADCB) cultivated under blue monochromatic LED light and ADC (the negative control) cultivated under dark conditions, their morphological characteristics were tested and LC/MS analyses were conducted. ADCB exhibited a greenish hue compared with ADC and contained increased levels of specific compounds. The anti-inflammatory activities of the two samples were evaluated using LPS-stimulated macrophages. None of the samples exhibited cytotoxicity at any tested concentration. However, ADCB demonstrated a greater ability to reduce nitric oxide and key pro-inflammatory cytokines including interleukin-1β, interleukin-6, and tumor necrosis factor-α compared to the control. Furthermore, ADCB effectively suppressed the expression of inducible nitric oxide synthase and cyclooxygenase-2. It inhibited the phosphorylation of mitogen-activated protein kinase family proteins, including extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38, in a concentration-dependent manner. Tissue culture and LED cultivation technologies are significant methods for addressing plant supply challenges and enhancing the content of bioactive compounds, thereby increasing the applicability of plant materials. Moreover, ADCB produced using these technologies exhibited anti-inflammatory activity without causing irritation to human skin at active concentrations, suggesting its potential as a novel anti-inflammatory material.