A phytochemical investigation of Stemona parviflora roots reveals several compounds with nematocidal activity

Twelve undescribed compounds including six phenanthrene derivatives (parviphenanthrines A-F), two stilbene derivatives (parvistilbines A-B), three esters (parviesters A-C), and one sesquiterpenoid (parvidiol A) were isolated from the roots of Stemona parviflora, together with twenty-two known ones. The structures of the undescribed compounds were elucidated based on the analyses of their spectroscopic data. The absolute configuration of parviphenanthrine A was determined by the quantum ECD calculations. Parviphenanthrines A and E, stemanthrene A, stilbostenin E, 4-hydroxy-benzenepropanol-α-benzoate, and (E)-4-hydroxycinnamic acid methyl ester showed nematocidal activity against Meloidogyne incognita with IC₅₀ values of 14.02 ± 0.32, 2.51 ± 0.13, 17.10 ± 0.65, 2.05 ± 0.07, 4.22 ± 0.31, and 1.07 ± 0.05 μM, respectively.