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BioMed Research International
Volume 2018, Article ID 3684845, 8 pages
https://doi.org/10.1155/2018/3684845
Research Article

Inhibitory Effects of Compounds and Extracts from Ampelopsis brevipedunculata on IL-6-Induced STAT3 Activation

Immunoregulatory Material Research Center, Korea Research Institute of Bioscience and Biotechnology, 181 Ipsin-gil, Jeongeup-si, Jeonbuk 56212, Republic of Korea

Correspondence should be addressed to Seung Woong Lee; rk.er.bbirk@codwsl and Mun-Chual Rho; rk.er.bbirk@m-ohr

Received 29 December 2017; Accepted 19 March 2018; Published 10 June 2018

Academic Editor: Fabrizio Montecucco

Copyright © 2018 Hyun-Jae Jang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Ampelopsis brevipedunculata (Maxim.) Trautv. (AB), a traditional East Asian medicine, exhibits protective effects against several inflammatory diseases. Our search for an inhibitor of IL-6-induced JAK2/STAT3 activation revealed that AB ethanolic extract (ABE) had a significant inhibitory effect on IL-6-induced STAT3 expression in Hep3B cells. The isolation and purification of an EtOAc-soluble fraction of ABE (ABEA) using reversed-phase high-performance liquid chromatography (RP-HPLC) afforded 17 compounds. The structures of these compounds (1-17) were elucidated based on 1H and 13C nuclear magnetic resonance (NMR) spectroscopy as well as electrospray-ionization mass spectrometry (ESI-MS) data. ABE and ABEA were screened by a luciferase assay using Hep3B cells transfected with the STAT3 reporter gene. ABEA exhibited potent inhibitory effects on IL-6-induced STAT3 expression; moreover, these effects arose from the inhibition of the phosphorylation of the STAT3, JAK2, and ERK proteins in U266 cells. In addition, the compounds isolated from ABEA were measured for their inhibitory effects on IL-6-stimulated STAT3 expression. Of the compounds isolated, betulin showed the greatest inhibitory effects on IL-6-induced STAT3 activation in the luciferase assay (IC50 value: 3.12 μM). Because of its potential for inhibiting STAT3 activation, A. brevipedunculata could be considered a source of compounds of pharmaceutical interest.