Isolation of new flavan-3-ol and lignan glucoside from Loropetalum chinense and their antimicrobial activities Qinghua Zhang, Dan Fan, Bingjian Xiong, Lingbao Kong, Xiangdong Zhu ⁎ College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, PR China article info abstract Article history: Received 12 May 2013 Accepted in revised form 2 August 2013 Available online 14 August 2013 Phytochemical and antimicrobial activity study on the ethanol extract of the leaves and stems of Loropetalum chinense led to the isolation of a new flavan-3-ol compounds, 8-[1-(3,4-dihydroxyphenyl)- 3-methoxy-3-oxopropyl]-catechin (loropetaliside A) (1) and a new lignan glucoside, 1-(5-hydroxy- 3-methoxyphenyl)-2-(2-β-glucopyranosyl-4-hydroxy-5-(1-(E)propen-3-ol)-phenyl)-propane-3-ol (loropetaliside B) (3) and several known compounds manglieside D (2), quercetin (4), kaempferol- 3-O-D-glucopyranoside (5), quercetin-3-O-β-L-rhamnoside (6) and tiliroside (7). Their structures were elucidated on the basis of extensive spectroscopic analysis. © 2013 Elsevier B.V. All rights reserved. Keywords: Loropetalum chinense Loropetaliside A Loropetaliside B Antimicrobial activity 1. Introduction Loropetalum chinense, a constant green shrub or small arbor, is widely grown in south of China and east of India. It belongs to the genus Loropetalum of Hamamelidaceae. Its leaves, flowers and roots are traditional medicines in China, which has been used to treat diarrhea, coughs, hemorrhaging, burn and various women's diseases [1]. The ethnopharmacology research of it showed that the medicinal effects are attributable to the tannins in this plant. Some oligomeric hydrolysable tannin such as loropetalins A–C, camelliin B and rougosins D, E, and G, have been isolated from the leaf of this plant [2,3]. In addition, some flavonids and related polyphenols have also been found from it [4]. However, little is known about the antimicrobial activities of the ethanolic extracts from the plant. As part of further phytochemical and antimicrobial activities investigations of the plant, the stems and leaves of L. chinense were collected from the suburb of Nanchang in Jiangxi province. In the present study, the antimicrobial activities of the extracts and the isolated compounds were investigated, meanwhile the structure of a new flavan-3-ol and lignan glucoside isolated from this plant was also elucidated (Fig 1). 2. Experimental 2.1. General Optical rotations were obtained on a Horiba SEPA-300 polarimeter. UV spectra were obtained on a Shimadzu 210A double-beam spectrophotometer, λ max in nm. IR spectra were taken on a Bio-Rad FTS-135 infrared spectrophotometer with KBr pellets. 1D and 2D- NMR spectra were recorded on Bruker AM-400 and DRX-500 instruments with TMS as internal standard, δ in ppm, J in Hz. EI-MS, ESI-MS and HR-ESI-MS were measured on Finnigan-MAT 90 and API QSTAR Pulsarimass spectrometers, respectively. Silica gel 200–300 mesh (Qingdao Marine Chemical Inc., China) and Sephadex LH-20 (Amersham Biosciences, Sweden) were used for column chromatography. Fractions were monitored by TLC (Qingdao Marine Chemical Inc., China). TLC spots were detected by spraying with 10% H 2 SO 4 in EtOH followed by heating. Fitoterapia 90 (2013) 228–232 ⁎ Corresponding author. Tel.:+86 791 3813459. E-mail address: zhuxdau@qq.com (X. Zhu). 0367-326X/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fitote.2013.08.003 Contents lists available at ScienceDirect Fitoterapia journal homepage: www.elsevier.com/locate/fitote