Objective To systematically investigate the chemical constituents of 70% acetone extract of Polygonatum cyrtonema processed by nine cycles of steaming and sun-drying. Method Compounds were isolated and purified by MCI gel, silica gel, Toyopearl HW-40C, ODS and semi-preparative HPLC. Their chemical structures were comprehensively elucidated by spectroscopic methods, such as HRESIMS, NMR, IR, UV and ECD. Results A total of 14 nitrogen-containing compounds were finally isolated and identified as 6-[(8R,9S)-8,9,10-trihydroxybutyl]-3,4-dimethylpyridazine (1), 6-ethyl-3-(hydroxymethyl)-1H-pyridin-2-one (2), (+)-(1R,3R)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (3), 1H-indole-3-carboxaldehyde (4), cyclo-(L-Leu-L-Phe) (5), cyclo-(L-Phe-L-Ile) (6), cyclo-(L-Asn-L-Phe) (7), (3S,6S)-3-benzyl-6-(1-hydroxyethyl)-2,5-piperazinedione (8), cyclo-(D-Phe-Gly) (9), cyclo-(L-Tyr-L-Tyr) (10), cyclo-(L-Val-L-Tyr) (11), pedatisectine L (12), cyclo-(Ala-Tyr) (13), and (2S,5S)-5-[(1S)-1-methylpropyl]-3,6-dioxo-2-piperazinepropanoic acid (14). Conclusion Compounds 1 and 2 were characterized as two new compounds named cyrtoneine J and cyrtoneine K, while compounds 3 and 5—14 were isolated from the genus Polygonatum for the first time.

Polygonatum cyrtonema Hua.  /  processing  /  nitrogen-containing  /  cyclo-(L-Leu-L-Phe)  /  cyrtoneine J  /  cyrtoneine K