Anti-inflammatory butanolides and lignanoids from the root of Machilus zuihoensis var. mushaensis

From the anti-inflammatory screening of Formosan Lauraceous plants, the methanolic extract of the root of Machilus zuihoensis var. mushaensis stood out for its potent inhibitory activity toward superoxide anion and elastase release in human neutrophils. Bioassay-guided fractionation of the root of M. zuihoensis var. mushaensis led to eight new compounds, including two butanolides (1-2), five lignanoids (3-7), and one sesquiterpenoid (8), along with 50 known compounds (9-58). Structures of these compounds were elucidated by NMR, UV, IR, CD, and MS analyses. Thirty-two isolates were evaluated for their anti-inflammatory activity. Among them, 9, 20, 27, 28, 30, 31, 35, and 40 exhibited significant superoxide anion generation inhibition selectively (IC₅₀ value < 7.4 μM), 15 and 19 showed selective inhibition toward elastase release (IC₅₀ value < 8.0 μM). Moreover, 3, 16, 21, and 22 simultaneously displayed superoxide anion generation and elastase release inhibition. It is worth mentioning that 21 and 22 showed more potent inhibitory activities (IC₅₀ < 1.0 μM) on superoxide anion than the positive control, LY294002. Further quantitative HPLC analysis indicated the content of 21 and 22 were 0.90 and 3.04 mg/g (w/w) in the ethyl-acetate layer of the root of M. zuihoensis var. mushaensis, respectively. Altogether, M. zuihoensis var. mushaensis revealed a potential for developing the botanical new drug against inflammation-related disease.