Chemical Constituents of the Leaves of (Korean Bellflower) and Their Inhibitory Effects on LPS-induced PGE Production.

Nakai (Campanulaceae; Korean bellflower) is one of the endemic herbs of Korea. The plant has been used as traditional medicines for treating asthma, tonsillitis, and sore throat in Korea. A hot water extract of the leaves of exhibited a significant inhibitory effect on lipopolysaccharide (LPS)-stimulated prostaglandin E (PGE) production. Repetitive chromatographic separation of the hot water extract led to the isolation of three new neolignan glucosides, campanulalignans A-C (-), with 15 known compounds (-). The structures of new compounds - were elucidated by analyzing nuclear magnetic resonance (NMR) spectroscopic data, along with high resolution quadrupole time of flight mass (HR-Q-TOF-MS) spectrometric data. Among the isolates, simplidin (), 5-hydroxyconiferaldehyde (), icariside F (), benzyl--l-arabinopyranosyl-(1″→6')--d-glucopyranoside (), and kaempferol 3---d-apiosyl (1→2)--d-glucopyranoside () were isolated from the Campanulaceae family for the first time. The isolates (, , and -) were assessed for their anti-inflammatory effects on LPS-stimulated PGE production on RAW 264.7 cells. 7,8-Dihydrodehydrodiconiferyl alcohol (), 3',4--dimethylcedrusin 9---glucopyranoside (), pinoresinol di---d-glucoside (), ferulic acid (), 5-hydroxyconiferaldehyde (), and quercetin () showed significant inhibitory effects on LPS-stimulated PGE production.