Characterization and quantification of the phytochemical constituents and anti-inflammatory properties of Lindera aggregata.

The dry roots of Lindera aggregata (Sims) Kosterm have a long-standing history in traditional Chinese medicine, renowned for their ability to regulate vital energy, relieve pain, warm the kidney, and dissipate cold. Recently, L. aggregata has been approved as a new food resource. To gain insights into the bioactive phytochemicals in L. aggregata, an ultrahigh-performance liquid chromatography coupled with high-resolution electrospray ionization quadrupole orbitrap spectrometry method was developed to investigate the chemical profiles of the ethanol extract of L. aggregata. This approach identified 80 compounds, predominantly alkaloids and sesquiterpenoids. Furthermore, 16 selected compounds were simultaneously quantified using the parallel reaction monitoring mode. The quantification method was validated and showed good linearity, sensitivity, and accuracy. The anti-inflammatory activities of the ethanol extract and selected compounds were assessed in vitro using lipopolysaccharide-stimulated RAW 264.7 macrophages. The results revealed that the ethanol extract of L. aggregata and norisoboldine, isolinderalactone, methyllinderone, and linderin B inhibited the production or expression of nitric oxide, inducible nitric oxide synthase (iNOS), tumor necrosis factor-α, and interleukin-6. Molecular docking of iNOS with isolinderalactone, methyllinderone, and linderin B showed that hydrogen bonds, π-π interactions, and hydrophobic interactions contributed to their iNOS inhibitory effects. The results offer insights that may be instrumental in enhancing the quality control for L. aggregata.