[Two new indole alkaloids from Nelumbinis Folium and their hypolipidemic activities]

Using modern chromatographic separation techniques such as silica gel, Sephadex LH-20, Toyopearl HW-40C column chromatography, and semi-preparative high-performance liquid chromatography, this study isolated 15 compounds from the 90% ethanol extract of Nelumbinis Folium. Their structures were identified by spectroscopic methods including ultraviolet(UV) spectroscopy, infrared(IR) spectroscopy, high-resolution electrospray ionization mass spectrometry(HR-ESI-MS), and nuclear magnetic resonance(NMR) spectroscopy. These compounds were identified as 1-(13,14-dimethoxybenzoyl)-3-[(8″E)-3″,4″,5″-trimethoxyphenylacetyl]-5-(1'-O-β-D-glucopyranosyl)-indole alkaloid(1), 2-(13-N-methyl-16,17-dimethoxyphenylacetyl)-3-(1'-O-β-D-glucopyranosyl)-7-methoxyindole alkaloid(2), isatindigoside A(3), isatindigoside B(4), wuzhuyuluckid A(5), wuzhuyuluckid B(6), wuzhuyuluckid C(7), talatensindoid B(8), talatensindoid C(9), isatisindigoticanine L(10), isatindigoside M(11), isatisindigoticanine M(12), isatisindigoticanine N(13), 1-methoxy-2-indoleacetonitrile(14), and 1-hydroxy-3-indoleacetonitrile(15). Among them, compounds 1-2 were determined as novel compounds, while compounds 3-15 were isolated from this plant for the first time. The novel compounds 1-2(50 μmol·L~(-1)) exhibited inhibitory effects on pancreatic lipase activity with inhibition rates of 68.38%±1.15% and 66.59%±1.13%, respectively. The novel compounds 1-2(50 μmol·L~(-1)) also suppressed the accumulation of triglycerides and neutral lipids in HepG2 cells with accumulation rates of 44.25%±0.95%, 52.81%±1.65% and 53.27%±0.97%, 67.08%±1.49%, respectively. Therefore, the novel compounds 1-2 demonstrated certain hypolipidemic activities.