Objective To study the alkaloids from the fruit of Lycium chinense and their hepatoprotective activity. Methods The compounds were isolated and purified by silica gel column chromatography, D101 macroporous resin column chromatography, ODS column chromatography, and semi-preparative HPLC. Their structures were identified by¹H-NMR, ¹³C-NMR and mass spectrometry. The acetaminophen (APAP)-induced injury of human liver cancer HepG2 cells model was used to evaluate the hepatoprotective activity of these compounds. Results Sixteen alkaloids were isolated from the ethanol extract of fruit of L. chinense. Their structures were identified as lyciumamide P (1), lyciumamide Q (2), lyciumamide R (3), N-cis-grossamide (4), cannabisin E (5), cannabisin F (6), cannabisin G (7), cannabisin H (8), heliotropamide (9), N-malonyl-tryptophan (10), N-acetyltryptophan methyl ester (11), equisetinine A (12), nicotinamide (13), methyl-5-hydroxy-2-pyridinecarboxylate (14), thymidine (15), N¹,N¹⁰-di-dihydrocaffeoylspermidine (16). Conclusion Compounds 1—16 were isolated from L. chinense for the first time. Compounds 12, 13, 15 and 16 were isolated from Lycium for the first time. Compounds 5—7 and 10—16 showed significant hepatoprotective activity against APAP-induced injury of human liver cancer HepG2 cells at 10 μmol/L.

Lycium chinense Mill.  /  alkaloids  /  hepatoprotective activity  /  cannabisin G  /  nicotinamide  /  methyl-5-hydroxy-2-pyridine-carboxylate