Metabolic profiling and anti-neuroinflammatory effects of Liriope platyphylla extract in LPS-stimulated BV2 microglia

초록

Liriope platyphylla F. T. Wang & T. Tang (L. platyphylla) is a perennial member of the Liliaceae family, is predominantly found in East Asian regions such as Korea, Taiwan, and Japan. In this study, we investigated the neuroinflammationmodulating potential of an ethanol-based extract from L. platyphylla (LPE) using BV2 microglial cells activated by lipopolysaccharide (LPS). In addition, we examined which bioactive constituents in LPE contribute to its anti-neuroinflammatory effects by isolating and profiling the major compounds. Notably, treating LPE prior to LPS exposure led to a marked decrease in the synthesis of inflammatory mediators, including cyclooxygenase-2 (COX-2), nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), and pro-inflammatory cytokines such as IL-6, IL-1β, and tumor necrosis factor-α (TNF-α) in the microglia. Mechanistic studies revealed that suppressive effects of LPE are linked to the downregulation of LPS-triggered signaling pathways, specifically those involving Toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), and the p38 and JNK branches of the mitogenactivated protein kinase (MAPK) cascade. Chemical analysis of the extract identified eight distinct compounds, with methylophiopogonone A (2) and methylophiopogonanone B (3) being primarily responsible for the observed anti-neuroinflammatory activity. Quantitative profiling by ultra-performance liquid chromatography coupled with quadrupole time of flight / mass spectrometry (QTOF/MS) indicated that these two bioactive constituents were present in the ethyl acetate fraction of LPE at concentrations of 0.0007 ± 0.0001 mg/g and 0.0197 ± 0.0009 mg/g, respectively. Collectively, these findings highlight the promise of LPE as a source for developing novel functional ingredients or herbal therapeutics targeting neuroinflammatory conditions.

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