Isolation of a novel catechin from Bergenia rhizomes that has pronounced lipase-inhibiting and antioxidative properties Sergey A. Ivanov a , Kenzo Nomura b , Ilya L. Malfanov a , Ilya V. Sklyar a , Leonid R. Ptitsyn a, ⁎ a Ajinomoto-Genetika Research Institute, 1-st Dorozhny pr. 1-1, Moscow 117545, Russia b Research Institute for Health Fundamentals, 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi 210-8681, Japan article info abstract Article history: Received 28 July 2010 Accepted in revised form 23 September 2010 Available online 12 October 2010 An aqueous ethanol extract of Bergenia crassifolia rhizomes strongly inhibited human pancreatic lipase activity and increased scavenging of DPPH free radicals in vitro. Chromatographic separation of this extract led to isolation of the hydrolysable tannins (+)-catechin 3,5-di-O-gallate (1) and (+)-catechin 3-O-gallate (2). This is the first report of the isolation of compound 1 from plant material. This compound strongly inhibited human pancreatic lipase (with an IC 50 value of 0.42 μg/ml) and exhibited a remarkable free radical-scavenging ability (with an SC 50 value of 1.04 μg/ml). The chemical structures of 1 and 2 were elucidated using MS, NMR and chemical approaches. © 2010 Elsevier B.V. All rights reserved. Keywords Human pancreatic lipase (HPL) Antioxidants Inhibition (+)-Catechin 3,5-di-O-gallate 1. Introduction The use of compounds that inhibit the digestion and absorption of nutrients is an important strategy in the treatment of obesity. These compounds help to reduce energy intake through gastrointestinal mechanisms [1–3]. Because dietary lipids represent a major source of unwanted calories, specifically inhibiting human pancreatic lipase (HPL), which is responsible for the hydrolysis of 50–70% of total dietary fats, is an effective approach to reduce fat absorption [1,4,5]. To discover biologically active anti-obesity agents from natural herbal resources, various plants have been screened for their anti-lipase activity. HPL inhibitors include sub- stances belonging to various chemical classes, such as polyphenolics (green-tea and grape-seed polyphenols, fla- vones, flavonols, tannins, and chalcones), saponins, terpenes, and others [6]. In addition to obesity, disrupted lipid metabolism causes a variety of other serious diseases, such as hypertension, functional depression of certain organs, and atherosclerosis [6]. Uncontrolled lipid peroxidation also contributes to the development of atherosclerosis [7]. Natural dietary antioxi- dants, such as vitamin E [8] and plant polyphenolic compounds [9,10], diminish free-radical-dependent lipoperoxidation. Bergenia crassifolia (Siberian tea, elephant ear; Saxifragaceae) is widely used in Russian ethnomedicine [11]. Extracts from the roots and leaves of this plant include antidiarrheal [11,12], anti- inflammatory [13], antioxidant [14,15], antiviral [16], antimicro- bial [17], diuretic [18], and immunostimulating [19,20] com- pounds. A prominent feature of B. crassifolia is the simultaneous presence of both green (young) and black (wintered) leaves on a single plant. Buryats and Mongols use B. crassifolia old blackened wintered leaves as a tea. The tea is popular as a health beverage as it contains no harmful stimulants such as caffeine [11,21]. Black leaves which have passed two winters are used as the adaptogen [22]. The phytochemical constituents of this plant include (+)-catechin 3-O-gallate, polymeric proanthocyanidins [23], the pectic polysaccharide bergenan [19], arbutin [24], gallic acid, and significant amounts of other phenolic compounds, such as flavonoids, phenolic acids, phenols, coumarins, and tannins [25]. The phenolic content varies according to the type of leaf [15,18]. All of the compounds listed above, except for coumarin and bergenin, are capable of scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH · ) free radi- cals. The antioxidant activity of the green-leaf extract is due to a Fitoterapia 82 (2011) 212–218 ⁎ Corresponding author. Tel.: +7 495 315 23 30; fax: +7 495 315 06 40. E-mail address: leonid_ptitsyn@agri.ru (L.R. Ptitsyn). 0367-326X/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.fitote.2010.09.013 Contents lists available at ScienceDirect Fitoterapia journal homepage: www.elsevier.com/locate/fitote