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Dibenzylbutyrolactone-type lignans are phenolic compounds of medical importance. The purpose of the study was to determine the effects of two such lignans, arctigenin and trachelogenin on the motility of isolated rat ileum and obtain indications on their mechanism of action. They were isolated from Arctium lappa and Cirsium arvense, respectively, which have been used traditionally to treat gastrointestinal disorders. 1–1.5 cm long segments of distal ileum were obtained from adult male Wistar rats. The intestinal segments were suspended vertically in a well-aerated organ-bath according to Magnus mounting method. The intestinal motility was monitored for 30 min before treatment to obtain the baseline, followed by treatment with 1 µM, 10 µM, 20 µM and 40 µM concentrations of arctigenin and 0.5 µM, 1 µM, 10 µM and 20 µM of trachelogenin concentrations. The amplitude, tone, and period of spontaneous contractions were measured after 15 and 30 min of treatment. To investigate their mechanism of action, cholinergic, glutamatergic, adrenergic antagonists and compounds inhibiting nitric oxide synthase and L-type calcium channels were also tested. Arctigenin and trachelogenin decreased the frequency of contractions in a dose-dependent manner. At the concentration of 20 µM and 40 µM of trachelogenin and arctigenin, respectively, there was a marked alteration in spontaneous contraction pattern with an observable increase in the period time. This activity was comparable to 0.5 µM nifedipine (L-type calcium channel blocker) treatment. Our results demonstrate relaxant effect of arctigenin and trachelogenin on the ileum motility that may be mediated by L-type calcium ion channel blockade.

The molecular constituents of Cirsium brachycephalum fruits were identified, quantified and isolated for the first time. The lignan glycoside tracheloside was the main compound, which was transformed quantitatively into its aglycone trachelogenin by endogenous enzymatic treatment of the fruit. Following this transformation by high performance liquid chromatography (HPLC) hyphenated with UV and mass spectrometry (MS) detections on a quantitative basis, the enzyme-hydrolyzed fruit was found to be the richest raw material containing trachelogenin (17.2mg/g) reported to date. Thus, the enzyme-hydrolyzed fruit was used to isolate trachelogenin using preparative HPLC in order to (1) unambiguously confirm its identity by gas chromatography-MS, nuclear magnetic resonance spectroscopy and optical rotation, and (2) investigate its in vitro antiproliferative activities against the SW480 colon adenocarcinoma cell line. Trachelogenin significantly affected the phosphorylation of key proteins such as β-Catenin, c-Myc and GSK3 in the β-Catenin signaling pathway in a concentration-dependent manner. These changes account for the antiproliferative effects of trachelogenin., (Copyright © 2014 Elsevier B.V. All rights reserved.)