Dammarane-Type Glycosides from Gynostemma pentaphyllum and Their Effects on IL-4-Induced Eotaxin Expression in Human Bronchial Epithelial Cells Tran Manh Hung, † Cao Van Thu, ‡ To Dao Cuong, † Nguyen Phi Hung, § Seung Jun Kwack, | Jung-Im Huh, 3 Byung Sun Min,* ,† Jae Sue Choi, ⊥ Hyeong Kyu Lee, 4 and KiHwan Bae* ,0 College of Pharmacy, Catholic UniVersity of Daegu, Kyeongbuk 712-702, Korea, Hanoi UniVersity of Pharmacy, 13-15 Le Thanh Tong, Hanoi, Vietnam, College of Pharmacy, Chosun UniVersity, Gwangju 501-759, Korea, National Institute of Toxicological Research, Seoul 122-704, Korea, Korea Institute of Toxicology, Daejeon 305-343, Korea, Faculty of Food Science and Biotechnology, Pukyung National UniVersity, Busan 608-737, Korea, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-600, Korea, and College of Pharmacy, Chungnam National UniVersity, Daejeon 305-764, Korea ReceiVed October 21, 2009 Two new dammarane-type glycosides, 2R,3,12,20S-tetrahydroxydammar-24-ene-3-O-[-D-glucopyranosyl(1f4)-- D-glucopyranosyl]-20-O-[-D-xylopyranosyl-(1f6)--D-glucopyranoside] (1) and 2R,3,12,20S-tetrahydroxydammar- 24-ene-3-O--D-glucopyranosyl-20-O-[-D-6-O-acetylglucopyranosyl-(1f2)--D-glucopyranoside] (2), were isolated from a MeOH extract of the leaves of Gynostemma pentaphyllum. Their structures were elucidated by 1D and 2D NMR spectroscopic interpretation as well as by chemical studies. The isolated compounds showed potential inhibitory effects on eotaxin expression in BEAS-2B bronchial epithelial cells. Asthma is defined as an obstructive disease of the pulmonary airways resulting from spasms of airway muscle, increased mucus secretion, and inflammation. The interaction between bronchial epithelial cells and eosinophils is an important feature of an asthma attack. Most evidence suggests that eosinophilic infiltration and activation may account for the spasmodic and cyclic nature of hyper-reactive airways. 1 The mechanisms underlying the selective recruitment of eosinophils are complex and include multistep processes, probably mediated by the cooperative action between cytokines that cause eosinophil priming and increase survival, interleukin [IL]-3 and IL-5 and granulocyte macrophage colony stimulating factor, and those that activate the endothelium IL-1, tumor necrosis factor (TNF)-R, IL-4, IL-13, and eosinophil-selective chemoattractant molecules, especially C-C chemokines. 2 Eotaxin is a C-C chemokine implicated in the recruitment of eosinophils in a variety of inflammatory disorders and, unlike all other eosinophil chemoattractants, is eosinophil-specific. 3 This character- izes eotaxin as a key mediator in allergic diseases of which eosinophilic infiltration is characteristic. 3,4 Cultured bronchial epithelial cells, including the normal bronchial epithelium, have been observed to produce eotaxin after stimulation with TNF-R and T helper (Th) type 2 cytokines. 5 Gynostemma belongs to the family Cucurbitaceae, and plants in this genus are known in mainland China as “xiancao”, or “herb of immortality”. 6 They have been used in folk medicine to lower cholesterol levels, regulate blood pressure, strengthen the immune system, and reduce inflammation. 7 Gynostemma species taste sweet and aromatic and can be taken either as a tea or with alcohol. Previous investigations of this genus have shown the occurrence of dammarane-type glycosides called the gypenosides, which are structurally related to ginseng saponins 8 and exhibit various biological activities. 9 Certain gypenosides have been reported to inhibit the proliferation of Hep-3B and HA22T cells, by affecting calcium and sodium currents in a dose-dependent manner. 10 In Vietnam, Gynostemma pentaphyllum is used as a traditional tea due to its sweetness, has efficacy in the treatment of elevated cholesterol, and exhibited antitumor, antioxidant, antidiabetes, and hypoglycemic effects, 11 as reported in a number of studies. 9,12 Recently, the effect exerted by G. pentaphyllum extract and its dammarane constituents on PTP1B has been studied. 13 However, no data are available on the influence of the components on eotaxin expression in BEAS-2B bronchial epithelial cells in vitro. In the present study, we report the isolation and structure elucidation of two new dammarane-type glycosides (1 and 2). In addition, the ability of these gypenosides to suppress eotaxin expression stimu- lated by the Th2 cytokine IL-4 alone and/or in combination with TNF-R in BEAS-2B cells was determined. Results and Discussion Repeated column chromatography of the n-BuOH-soluble frac- tion of the 70% EtOH extract of G. pentaphyllum leaves resulted in the purification of 1 and 2. Compound 1 was obtained as an amorphous powder. The molecular weight was determined from * To whom correspondence should be addressed. (M.S.B.) Tel: +82- 53-850-3613. Fax: +82-53-850-3602. E-mail: bsmin@cu.ac.kr. (K.H.B.) Tel: +82-42-821-5925. Fax: +82-42-823-6566. E-mail: baekh@cnu.ac.kr. † Catholic University of Daegu. ‡ Hanoi University of Pharmacy. § Chosun University. | National Institute of Toxicological Research. 3 Korea Institute of Toxicology. ⊥ Pukyung National University. 4 Korea Research Institute of Bioscience and Biotechnology. 0 Chungnam National University. J. Nat. Prod. 2010, 73, 192–196 192 10.1021/np9006712  2010 American Chemical Society and American Society of Pharmacognosy Published on Web 01/27/2010