Journal of Chromatography A, 1151 (2007) 175–179 Isolation and purification of antioxidative isomeric polyphenols from the roots of Parthenocissus laetevirens by counter-current chromatography Shan He, Yanbin Lu, Bin Wu, Yuanjiang Pan ∗ Department of Chemistry, Zhejiang University, Hangzhou 310027, China Available online 4 March 2007 Abstract Upright counter-current chromatography (CCC) with a two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (1:2:1:2, v/v/v/v) was applied to the isolation and purification of polyphenols from the roots of Parthenocissus laetevirens. Two cis-trans isomeric resveratrol dimers – quadrangularin A and parthenocissin A – were obtained from the crude sample in a one-step separation, with purities of 95.4 and 97.6%, respectively, as determined by HPLC. The structures of these two compounds were identified by 1 H NMR and 13 C NMR. Furthermore, their antioxidant activities were determined by -carotene bleaching assay. The antioxidant activities of quadrangularin A and parthenocissin A were higher than that of vitamin C in this model. © 2007 Elsevier B.V. All rights reserved. Keywords: Parthenocissus laetevirens; Counter-current chromatography; Polyphenol; Antioxidant 1. Introduction Recently, attention has been drawn to stilbene and its oligomers because of their various biological properties such as antioxidant [1], hepatoprotective [2], anti-tumor [3] and cancer chemopreventive activities [4]. In addition, polyphenols from red wine, mainly stilbene derivatives, were reported to be linked with the so-called “French paradox”—despite a high fat intake, mortality from coronary heart disease is lower in some regions of France due to the regular consumption of red wine [5]. The genus Parthenocissus (Vitaceae family) is known to be a rich source of stilbene derivatives, nevertheless, phytochemical stud- ies on these plants are scarce [6]. Parthenocissus laetevirens Rehd. is usually planted as a cover crop in east China and tradi- tionally used as folk medicine for the treatment of rheumatism. So far, no phytochemical or pharmacological investigation on P. laetevirens has been reported. Generally, some conventional methods including silica gel, polyamide and preparative reversed-phase liquid chromatog- raphy are often used to isolate pure products from medicinal plants, but they are tedious, time consuming, requiring multi- ple chromatographic steps [7]. Counter-current chromatography (CCC) is an unique liquid–liquid partition chromatography with- ∗ Corresponding author. Tel.: +86 571 87951264; fax: +86 571 87951629. E-mail address: panyuanjiang@zju.edu.cn (Y. Pan). out use of solid support matrix [8]. Therefore, it eliminates the complications resulting from the solid support matrix, such as irreversible adsorptive sample loss and deactivation, tailing of solute peaks and contamination [9]. Recently, the method has been successfully applied to the analysis and separation of various polyphenols from plant extracts [7,10–13]. Herein, upright counter-current chromatography with two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water was developed and applied to the separation and purification of polyphenols from the crude sample of P. laetevirens. Two cis-trans isomeric resveratrol dimers, quadrangularin A [14] and parthenocissin A [6], were obtained in a one-step separation. The chemical structures of these polyphenols are shown in Fig. 1. Furthermore, their antioxidant activities were assayed. 2. Experimental 2.1. Apparatus The CCC isolation and purification of two polyphenols from the roots of P. laetevirens was performed by upright coil planet centrifuge with four multilayer coils connected in series. Its design principle and dimensions were described in a previ- ous communication [15]. The upright CCC apparatus holds four identical multilayer coil columns in symmetrical posi- tions around the rotary frame at a distance of 9 cm from the 0021-9673/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2007.02.102