ABSTRACT
Numerous effective anticancer drugs have been developed from botanical sources, and there remains a significant untapped resource in herbal medicines. In this study, we evaluated the chemical composition of extracts from American ginseng after steaming, the antiproliferative effects of the ginsenosides in the extracts on SW-480 human colorectal cancer cells, and their apoptotic mechanisms. American ginseng roots were steamed at 120 degrees C for 2 or 4 h. Representative ginsenosides in the unsteamed and steamed extracts were determined using HPLC. The antiproliferative effects of the ginsenosides Rb1, Rg3 and Rh2 on SW-480 cells were determined by the MTS method. The effect of extract steamed for 4 h on apoptosis of SW-480 cell was assayed by flow cytometry after staining with annexin V/PI. The expression of 84 apoptotic-related genes, including TNF, mitochondria and p53 pathways, was determined using real-time quantitative PCR array analysis. The mitochondrial membrane potential (Deltapsim) was analyzed after staining with FC-1. Steaming of American ginseng increased Rg3 and Rh2 content and antiproliferative activity significantly. The quantitative PCR array data demonstrated that multiple genes in mitochondrial pathway are involved in American ginseng-induced apoptosis of SW-480 cells and the expression profiling was validated by the cellular functional assay. The mitochondrial pathway may play a key role in American ginseng-mediated cancer cell apoptosis.
Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Colonic Neoplasms/pathology , Membrane Potential, Mitochondrial/drug effects , Panax/chemistry , Plant Extracts/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Chromatography, High Pressure Liquid , Colonic Neoplasms/genetics , Colonic Neoplasms/metabolism , Flow Cytometry , Gene Expression/drug effects , Gene Expression Profiling , Ginsenosides/pharmacology , Humans , Plant Extracts/chemistry , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Previous studies showed that both American ginseng root and American ginseng berry extracts possess hypoglycemic properties. In this study, we investigated whether American ginseng leaves also have similar capabilities. We first analyzed the chemical constituents of American ginseng leaf and determined the content of six major ginsenosides, i.e., Rb(1), Rb(2), Rc, Rd, Re, and Rg(1), by high performance liquid chromatography (HPLC). Subsequently, we evaluated the hypoglycemic effect of American ginseng leaf extract (AGLE) in diabetic ob/ob adult mice. Animals received daily intraperitoneal injections of AGLE 50, 150 mg/kg or vehicle for 12 consecutive days. Fasting blood glucose levels, intraperitoneal glucose tolerance test (IPGTT), body weight and temperature were measured. On day 5, the 150 mg/kg AGLE group had significantly lower fasting blood glucose levels compared to vehicle-treated mice (223.0+/-13.9 mg/dl versus 258.0+/-14.0 mg/dl, P<0.05), while the blood glucose levels in 50 mg/kg group did not decrease significantly. On day 12, the glucose levels in both AGLE-treated groups were reduced significantly compared to vehicle group (180.0+/-10.0 mg/dl and 220.2+/-19.3 versus 268.0+/-10.0 mg/dl, P<0.01 and <0.05, respectively). IPGTT data showed that both AGLE 150 and 50 mg/kg groups significantly increased the glucose disposal on day 12 compared to the vehicle group. In addition, body weight decreased in ob/ob mice after AGLE treatment, and these body weight changes were accompanied by significant increases in body temperature (P<0.05). Our results suggest that AGLE possesses a significant anti-hyperglycemic and thermogenic activity and may prove to be beneficial in improving the management of type 2 diabetes.
