Isolation and identification of the alkaloids from rhizomes of Stephania macrantha

Abstract

To study the alkaloids in the rhizomes of Stephania macrantha. The total alkaloids of S. macrantha were extracted by acid extraction and alkali precipitation method. Eleven alkaloids have been isolated and purified by silica gel column chromatography and preparative high performance liquid chromatography (HPLC). The structures of compounds were identified by spectroscopic methods (NMR and MS). The results were as follows: (1) Eleven compounds were designated as sinomenine (1), sinoactine (2), stepharine (3), reticuline (4), isocorydine (5), corydalmine (6), asimilobine (7), sukhodianine (8), dicentrine (9), 7-oxocrebanine (10) and palmatine (11). (2) The total alkaloids of S. macrantha and sinomenine had inhibitory activities on human lung cancer cells (A549), with IC50 values of 7.5×10-4 g·mL-1 and 6.59×10-9 g·mL-1, respectively. Compounds 2, 3, 4, 7, 8, 9 and 10 were isolated for the first time from S. macrantha. The chemical constituents from S. macrantha belong to five types of alkaloids such as morphanes, proaporphines, aporphines, benzyltetrahydroi soquinolines and protoberberines.

Keywords

• stephania macrantha
• alkaloids
• chemical constituents
• isolation and purification
• structural identification
• cytotoxicity