Sesquiterpenes and alkaloids from the roots of Alangium chinense.
Four new sesquiterpenes (1-4), four new alkaloids (5a, 6a, 6b, and 7), and nine known compounds (5b and 8-15) were isolated from an ethanolic extract of roots of Alangium chinense. The structure of 1 was confirmed by X-ray crystallography. The configurations of 5 and 6 were assigned by chiral HPLC analysis and CD spectra. Compounds 3, 4, 8-13, and 15 exhibited antiviral activity against Coxsackie virus B3 with IC50 values of 1.4-15.4 μM. Compounds 2-4, 7, and 9-13 showed antioxidant activities against Fe(2+)-cysteine-induced rat liver microsomal lipid peroxidation, with IC50 values of 3.8-45.7 μM. Compound 5b displayed neuritis inhibitory activity against microglial inflammation factor, with an IC50 value of 6.7 μM. None of the compounds exhibited detectable cytotoxic activity toward any of five tumor cell lines (A549, Be-17402, BGC-823, HCT-8, and A2780) in the MTT assay.