Anti-Inflammatory and Antioxidant Properties of Bauhinia thailandica Leaf Extract in Microglial Cells

Neuroinflammation is pivotal in the development of numerous neurodegenerative disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Microglial cells, the principal immune cells of the central nervous system (CNS), are essential mediators of this process. Upon exposure to pathogenic stimuli such as lipopolysaccharide (LPS), microglia activate and release pro-inflammatory mediators, leading to heightened oxidative stress and neuronal damage. Therefore, targeting microglial activation is a promising therapeutic approach to prevent or slow neurodegeneration. This study aimed to investigate the antioxidant and anti-inflammatory effects of the leaf extract of the newly identified species Bauhinia thailandica on LPS-activated BV2 microglia. The phytochemical compound of the B. thailandica leaf extract was also investigated. BV2 cells were treated with LPS (1 μg/mL) for 24 h in the presence or absence of B. thailandica leaf extract (12.5 and 25 µg/mL). The levels of reactive oxygen species (ROS), nitric oxide (NO), and interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-alpha (TNF-α) were quantified with CM-H2DCFDA, Griess reagent assay, and ELISA, respectively. Treatment with LPS resulted in significant increases in ROS, NO, IL-6, IL-1, and TNF levels compared to untreated cells (p < 0.01). However, co-treatment with B. thailandica leaf extract significantly suppressed the production of these inflammatory markers (p < 0.01 for 25 µg/mL across all parameters, except TNF-α; p < 0.05). The results also showed that B. thailandica leaf extract possessed significant levels of total phenolic content (TPC; 70.55 mg GAE/g dry extract), total flavonoid content (TFC; 249.47 mg QE/g dry extract), and tannins (397.50 mg TAE/g dry extract). Phytochemical screening also revealed the presence of saponins and cardiac glycosides in the extract. In conclusion, the leaf extract of B. thailandica is a potent source of phytochemicals exhibiting antioxidant capabilities and has shown both antioxidant and anti-inflammatory actions in LPS-activated BV2 microglial cells. The findings indicate that B. thailandica leaf extract shows significant promise as a novel herbal treatment for neuroinflammatory disorders mediated by microglia. Further research is necessary to clarify the underlying mechanisms of action and to investigate the active substances responsible for these effects.