Structurally diverse neolignans from the root bark of Magnolia officinalis Rehd. et Wils with their bioactivities

Phytochemical analysis of the root bark of Magnolia officinalis Rehd. et Wils led to the isolation of six undescribed meroterpenoids (1-6) and eight novel magnolol analogues (7-14), together with eight known compounds (15-22). Their structures were elucidated by extensive analyses of NMR, HRESIMS and electronic circular dichroism (ECD) calculations. Bioactivity evaluation demonstrated that 7, 12 and 15 showed significant hepatoprotective activities in both APAP and H₂O₂ induced liver injury models, while 2, 4 and 12 displayed remarkable nephroprotective effects in a dose-dependent manner. Compound 15 was enriched and confirmed to exhibit significant anti-ulcer activity. Further investigation revealed that 15 preserved the integrity of the gastric mucus layer and enhanced the expression of gastric mucin proteins MUC6, as well as gastric mucosal proteins CFTR and SLC26A3, thereby strengthening the protective function of the gastric mucosal barrier in rats. Additionally, 15 inhibited apoptosis in gastric mucosal cells, further mitigating ethanol-induced gastric ulcer damage.