Anti-inflammatory Activity of Total Alkaloids in Nelumbo nucifera and Simultaneous Determination of Major Bisbenzylisoquinolines

Plumula nelumbinis , the green embryo of the mature seeds of Nelumbo nucifera Gaertn., Nelumbonaceae, is widely used in traditional Chinese medicine and possesses antioxidant and anti-inflammatory activities. However, few reports are available on the anti-inflammatory activity of alkaloids and main contents of alkaloids in P. nelumbinis . This study aims to systematically investigate the anti-inflammatory of total alkaloids fraction and determine the contents of three major alkaloids (liensinine, isoliensinine, and neferine) in P. nelumbinis collected from 13 habitats by ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry. Lipopolysaccharide-induced RAW 264.7 cells and 12- O -tetradecanoylphorbol-13-acetate-induced ear edema inflammatory model were used to evaluate in vitro and in vivo anti-inflammatory activities, respectively. Histopathological and immunohistochemical analyses were performed to determine histological morphology and related inflammatory factors. The total alkaloids exhibited the best anti-inflammatory activity, thereby significantly inhibiting the nitric oxide release in RAW 264.7 cells. In addition, liensinine (IC 50 5.02 μM), isoliensinine (IC 50 4.36 μM), and neferine (IC 50 4.13 μM) showed excellent anti-inflammatory activity. The total alkaloids reduced ear edema and significantly reduced the expression levels of interleukin 6, interleukin 1β, tumor necrosis factor α, and nuclear factor-kappa B in a dose-dependent manner. Total alkaloids in P. nelumbinis exhibited good anti-inflammatory activity, suggesting that they might act as anti-inflammatory agents. Graphical Abstract