RESUMEN
Objective: To study the chemical constituents from the stem barks of Aphanamixis polystachya. Methods: The constituents were isolated and purified by silica gel, Sephadex LH-20, ODS column chromatography, and preparative HPLC, and their structures were elucidated on the basis of their physicochemical properties and spectral data. Results: Three diterpenes were obtained from the ethanol extract of the stem bark of A. polystachya and identified as (2Z, 6E, 10E)-methyl 12, 14, 15-trihydroxy-3, 7, 11, 15-tetramethylhexadeca-2, 6, 10-trienoate (1), melidianolic acid A (2), and nemoralisin H (3), respectively. Conclusion: Compound 1 is a new linear diterpene named nemoralisin K, compound 2 is isolated from the plants of Aphanamixis Bl., and compound 3 is obtained from the species for the first time, respectively.