Homoisoflavanones, Alkaloid, and Norsesquiterpenoid from Polygonatum cyrtonema and Their Immunomodulatory Effects

Abstract

Polygonatum cyrtonema (Huang jing) is widely used in both the food and traditional Chinese medicine industries. A chemical investigation of the rhizome of cultivated P. cyrtonema yielded six previously undescribed compounds─one norsesquiterpenoid (1), one pyridine alkaloid (2), and four homoisoflavanones (3a, 4a, 5a, 6a)─together with 9 known compounds (3b, 4b, 5b, 6b, 7–11). Their structures were established on the basis of extensive spectroscopic data and quantum chemical calculations, including NMR, HRESIMS, and calculated ECD. The enantiomers of the C-6-methylated homoisoflavanones (3a/3b–6a/6b) were successfully isolated via chiral HPLC. All compounds were evaluated for their immunomodulatory activity using RAW264.7 macrophages at concentrations ranging from 3.125 to 25 μM. Only compounds 8 and 11 enhanced the proliferation and phagocytosis of RAW264.7 macrophages and upregulated the secretion of NO, IL-6, and TNF-α.