Two undescribed biphenyl cyclooctene lignans with anti-inflammatory and anti-oxidant activities from the fruits of <i>Schisandra grandiflora</i>

Two undescribed biphenyl cyclooctene lignans, Schisandrin H (<b>1</b>) and Schisandrin S (<b>2</b>), and two known compounds (<b>3</b>) and (<b>4</b>), were extracted from fruits of <i>Schisandra grandiflora</i>. Structural elucidation was achieved through integrated UV, HRESIMS, NMR, ECD and ORD data analysis. At 1 μmol/L, inhibition of LPS-induced NO production in RAW264.7 macrophages was 28.85 ± 4.60% (compound <b>2</b>), 8.36 ± 5.33% (<b>3</b>), 16.72 ± 4.42% (<b>4</b>) and 38.25 ± 2.54% for dexamethasone (positive control), relative to the model group. Additionally, all compounds were evaluated for <i>in vitro</i> anti-oxidant activity using DPPH and ABTS⁺ radical scavenging methods. Compounds <b>2</b> and <b>4</b> showed appreciable ABTS⁺ scavenging activity, with activity levels comparable to VC at higher concentrations.