A new neolignan and a new phenolic acid from the heartwood of Mansonia gagei J.R. Drumm.

One new neolignan ( 1 ) and one new phenolic compound ( 2 ), together with four known compounds ( 3 - 6) were isolated from the heartwood of Mansonia gagei . Their structures were elucidated by extensive spectroscopic analyses, including 1D and 2D NMR and HRESIMS. The absolute configuration of 2 was established based on the DP4+ protocol and by comparison of experimental and calculated ECD spectra. All isolated compounds were evaluated by DPPH assay for antioxidant activity, while compounds 3 - 6 were assayed using the MTT-based colorimetric assay for cytotoxicity against lung cancer cell line A549. In terms of antioxidant activity, 1 and 3 exhibited stronger activity (IC 50 14.91 ± 1.10 and 17.46 ± 0.16 μM, respectively) than the positive control, ascorbic acid (IC 50 30.20 ± 0.47 μM). Among the compounds tested for cytotoxicity, compound 3 showed the highest activity, with an IC 50 value of 26.04 ± 2.95 µM.