Lignans and neolignans from the twigs and leaves of Wikstroemia indica (L.) C.A. Mey. with their effects on LPS-induced IL-1β and IL-10 secretion in RAW 264.7 macrophages

Eight compounds were isolated from the water-soluble fraction of Wikstroemia indica (L.) C.A. Mey., including two new neolignans (isonitidanin-4-O-β-D-glucoside (3) and threo-citrusin B (6)), four known neolignans (1, 2, 4, and 5), along with two previously reported lignans (7 and 8). Spectral analysis (1D, 2D NMR, and HR-ESI-MS/MS) was used to identify their chemical structures. Except for compound 3, which was not evaluated due to limited sample availability, the influence of the remaining compounds on IL-1β and IL-10 secretion in LPS-stimulated RAW 264.7 macrophages was assessed using ELISA. Among these, compound 8 significantly reduced IL-1β secretion, with an IC₅₀ value of 9.73 ± 1.26 µM. These results not only expand the known chemical diversity of lignans from W. indica but also suggest that certain lignans possess promising anti-inflammatory activity and may serve as valuable lead compounds for the development of new immunomodulatory agents.