Comparison of chemical constitution and bioactivity among different parts of Lonicera japonica Thunb

Abstract BACKGROUND Lonicera japonica Thunb is a common herb in East Asia. The flower buds are usually regarded as the traditional medicinal part, while leaves and stems are considered less valuable and receive little attention. This study compared the chemical constituents and anti‐inflammatory effects of the different tissues in L. japonica Thunb for the first time. RESULTS Thirty compounds were identified by ultra‐performance liquid chromatography‐photodiode detector‐quadrupole / time of flight‐mass spectrometry (UPLC‐PDA‐Q/TOF‐MS/MS) analysis. Hydroxycinnamic acids, flavonoids, and iridoids were identified as the major components. The flower buds (FLJ), leaves (LLJ), and stems (SLJ) of L. japonica Thunb showed strong similarities in chemical components. The LLJ contained higher levels of hydroxycinnamic acids and flavonoids than the FLJ and SLJ. Furthermore, FLJ, LLJ, and SLJ exhibited potent anti‐inflammatory activity in croton oil‐induced ear edema and carrageenan‐induced paw edema assays in mice. Moreover, FLJ, LLJ, and SLJ showed a cytoprotective effect on lipopolysaccharide‐ (LPS‐) stimulated RAW 264.7 macrophages. Lipopolysaccharide‐induced increases in nitric oxide (NO), tumor necrosis factor‐ α (TNF‐ α ), interleukin‐1 β (IL‐1 β ), and interleukin‐6 (IL‐6) were suppressed by treatments of FLJ, LLJ, and SLJ, respectively. The LLJ possessed a stronger anti‐inflammatory effect than the FLJ. CONCLUSION Leaves and stems of L. japonica Thunb have chemical components and anti‐inflammatory properties similar to flower buds, and may become alternative or supplementary sources of flower buds. © 2019 Society of Chemical Industry