Sinhyotaklisan alleviates inflammation in LPS-activated macrophages by modulating the heme oxygenase pathway.

Ethnopharmacological Relevance: Shinhyotaklisan (SHTLS) is a time-honored traditional Korean herbal formula composed of four key herbs: Lonicerae Flos, Astragali Radix, Angelicae Gigantis Radix, and Glycyrrhizae Radix et Rhizoma. It has been extensively used to treat inflammatory diseases by expelling excessive heat, detoxifying the body, and promoting the drainage of pus from abscesses.

Aim Of The Study: This study examines the therapeutic effects of SHTLS and elucidates its mechanisms of action in alleviating lipopolysaccharide (LPS)-induced inflammation in vitro.

Materials And Methods: SHTLS was prepared by boiling four herbs in 30% ethanol, and its antioxidant and antimicrobial effects were assessed. Furthermore, SHTLS was applied to LPS-exposed RAW 264.7 cells, and its anti-inflammatory effects were evaluated using an MTT assay, nitric oxide (NO) and reactive oxygen species (ROS) assays, enzyme-linked immunosorbent assay, and western blotting.

Results: SHTLS demonstrated potent antioxidant and antimicrobial effects. It effectively suppressed LPS-induced inflammatory cascades, resulting in a significant reduction in pro-inflammatory cytokines, including IL-6 and TNF-α, in murine macrophage cells. Moreover, SHTLS decreased COX-2 and iNOS expression levels, primarily through the inhibition of NF-κB and MAPK signaling pathways. Additionally, SHTLS significantly reduced intracellular ROS and reactive nitrogen species levels by upregulating heme oxygenase-1 (HO-1) expression. The anti-inflammatory effects of SHTLS were diminished by the addition of an HO-1 inhibitor, underscoring its strong association with intracellular antioxidant mechanisms.

Conclusion: Our results suggest that SHTLS exhibits strong antioxidant and anti-inflammatory effects, primarily by upregulating HO-1 and inhibiting the NF-κB and MAPK pathways, highlighting its potential as a therapeutic agent for inflammation-related conditions.