Ginsenoside Rg3 in methanol extraction of heat-processed ginseng has antioxidative and antitumor effects [8]. Ginsenoside Rh2 is a major active anticancer saponin in ginseng extracts [9]. Ginsenoside Rh2 treatment modulates the protein expression level of p21 and cyclin D, and leads to a marked reduction in the proliferation of MCF-7 human breast cancer cells [10]. It also provokes apoptosis through activating p53 and inducing

the proapoptotic regulator Bax in colorectal cancer cells [11]. In addition, Rh2 markedly reduces the viability of breast cancer cells (MCF-7 and MDA-MB-231) by arresting the G1 phase cell cycle via p15 INK4B and p27 KIP1-dependent inhibition of cyclin-dependent Wnt inhibitor kinases [12]. Many studies on BG have been performed because interest in it has increased IDH cancer recently. The main component of BG is reportedly Rg5 (Fig. 1) [13]. Studies demonstrate it has diverse physiological activity such as anti-inflammatory effects on lipopolysaccharide-stimulated BV2 microglial cells [14], protective effects on scopolamine-induced memory deficits in mice [15], and inhibitory effects in a mouse model with oxazolone-induced chronic

dermatitis [16]. Rg5 reportedly blocks the cell cycle of SK-HEP-1 cells at the Gl/S transition phase by downregulating cyclin E-dependent kinase activity [17]. Breast cancer is a very common cancer in women worldwide. In the United States, it is estimated that breast cancer is the leading cause of all cancers (29%) and the second leading cause of death (14%) [18]. In

Korea, 16,015 new cases of breast cancer were reported in 2011 [19]. Anticancer activity of BG extract in the MCF-1 breast cancer cell line exhibited three-fold cytotoxicity, compared with Red ginseng Cyclin-dependent kinase 3 extract [20]. However, ginseng fine roots contain a higher content of ginseng saponin than ginseng main roots [2]. In the present study, we therefore aimed to investigate anti-breast cancer activity (in the MCF-7 cell line) and the action mechanisms of FBG ethanol extract (EE), FBG butanol fraction (BF; primarily containing saponin), and Rg5 as the major saponin. Fine Black ginseng (Panax ginseng Meyer) for experiments was purchased from Kumsan Town, Chungcheongnam Province, the Republic of Korea in August 2009. All other chemicals were of an analytical reagent grade. Distilled water for high-performance liquid chromatography (HPLC) and acetonitrile were purchased from J.T. Baker SOLUSORB (Philipsburg, NJ, USA). The standards were purchased from Chromadex (Santa Ana, CA, USA) and Ambo Institute (Seoul, South Korea). Proton magnetic resonance, carbon magnetic resonance, heteronuclear multiple quantum coherence and heteronuclear multiple bond coherence spectra were measured with INOVA-500 (500 MHz) (Varian). The mass spectrum was taken on a fast atom bombardment mass spectrometry device (JMS-700; Jeol, Seoul, Korea). For the experiments, Rg3 was purchased from Chromadex.