Botanical flavonoids on coronary heart disease

Ischemic heart disease (IHD) is one of the leading causes of death in Western countries. Prevention rather than treatment of heart disease can significantly improve patients' quality of life and reduce health care costs. Flavonoids are widely distributed in vegetables, fruits and herbal medicines. Regularly consuming botanicals, especially those containing flavonoids, has been associated with a reduction in cardiovascualar disease; thus, it is important to investigate how flavonoids improve cardiac resistance to heart disease and their related mechanisms of action. It has been shown that cardiomyocyte injury and death can result from ischemia-reperfusion, which is pathognomonic of ischemic heart disease. Massive reactive oxygen species (ROS) release at the onset of reperfusion produces cell injury and death. "Programming" the heart to either generate less ROS or to increase strategic ROS removal could reduce reperfusion response. Additionally, profuse nitric oxide (NO) release at reperfusion could be protective in "preconditioning" models. Botanical flavonoids induce preconditioning of the heart, thereby protecting against ischemia-reperfusion injury. In this article, we will discuss two herbs containing potent flavonoids, Scutellaria baicalensis and grape seed proanthocyanidin, which can potentially offer cardiac protection against ischemic heart disease.

American ginseng suppresses Western diet-promoted tumorigenesis in model of inflammation-associated colon cancer: role of EGFR

Background

Western diets increase colon cancer risk. Epidemiological evidence and experimental studies suggest that ginseng can inhibit colon cancer development. In this study we asked if ginseng could inhibit Western diet (20% fat) promoted colonic tumorigenesis and if compound K, a microbial metabolite of ginseng could suppress colon cancer xenograft growth.

Methods

Mice were initiated with azoxymethane (AOM) and, two weeks later fed a Western diet (WD, 20% fat) alone, or WD supplemented with 250-ppm ginseng. After 1 wk, mice received 2.5% dextran sulfate sodium (DSS) for 5 days and were sacrificed 12 wks after AOM. Tumors were harvested and cell proliferation measured by Ki67 staining and apoptosis by TUNEL assay. Levels of EGF-related signaling molecules and apoptosis regulators were determined by Western blotting. Anti-tumor effects of intraperitoneal compound K were examined using a tumor xenograft model and compound K absorption measured following oral ginseng gavage by UPLC-mass spectrometry. Effects of dietary ginseng on microbial diversity were measured by analysis of bacterial 16S rRNA.

Results

Ginseng significantly inhibited colonic inflammation and tumorigenesis and concomitantly reduced proliferation and increased apoptosis. The EGFR cascade was up-regulated in colonic tumors and ginseng significantly reduced EGFR and ErbB2 activation and Cox-2 expression. Dietary ginseng altered colonic microbial diversity, and bacterial suppression with metronidazole reduced serum compound K following ginseng gavage. Furthermore, compound K significantly inhibited tumor xenograft growth.

Conclusions

Ginseng inhibited colonic inflammation and tumorigenesis promoted by Western diet. We speculate that the ginseng metabolite compound K contributes to the chemopreventive effects of this agent in colonic tumorigenesis.

Bioactivity of American ginseng by knockout extract preparation using monoclonal antibody

We produced anti-ginsenoside Re (GRe)-4G10 monoclonal antibody that specifically recognizes GRe and used this to prepare an immunoaffinity column to remove GRe from American ginseng berry extract (AGBE) (thus producing GRe knock-out AGBE (GRe-KO-AGBE)). We compared the anti-diabetic and anti-obesity effects of AGBE and GRe-KO-AGBE in adult diabetic C57BL/6J ob/ob mice. Fasting blood glucose levels and body weight were measured in mice receiving daily intraperitoneal injections of 150 mg/kg of either extract for 27 consecutive days. On Day 6, the group taking AGBE had significantly lower fasting blood glucose levels compared to GRe-KO-AGBE-treated mice (70.5 mg/dl vs. 140 mg/dl). On Day 13, the glucose levels in both groups were 201 mg/dl for AGBE-treated group and 169 mg/dl for GRe-KO-AGBE, respectively. GRe (20 mg/kg) had dose-related effects on fasting blood glucose levels (reduced to 188 and 180 mg/dl on Day 5 and Day 12, respectively, compared to 229 and 235 mg/dl, respectively, in the vehicle group). This hypoglycemic effect persisted even after treatment discontinued (blood glucose levels at 3 days post-treatment: 198 and 253 mg/dl with ginsenoside and vehicle treatment, respectively). The monoclonal antibody technique can be used to prepare botanical knockout extracts for bioactivity studies.

Development of monoclonal antibody against isoquinoline alkaloid coptisine and its application for the screening of medicinal plants

In the development of immunoassay technique, the design of hapten containing a functional group suitable for protein conjugate is the key step for the preparation of antibodies against small molecules. Coptisine (MW 320), a bioactive constituent of Berberis and Coptis species, is small as an immunogen. In addition, coptisine has no reactive group in molecule for conjugating with a protein. To overcome this problem, 9-O-carboxymethyl-berberrubine was designed and conjugated with carrier protein. In order to confirm its immunogenicity, the ratio of hapten in the conjugate was determined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). After immunization, hybridomas secreting antibodies against coptisine were produced by fusing splenocytes with mouse myeloma cell line, P3-X63-Ag8-653. Among hybridomas, the clone 2A1 secreting anti-coptisine monoclonal antibody (MAb) 2A1-9E-1 was obtained through the limited dilution method. The MAb-based enzyme-linked immunosorbent assay (ELISA) against coptisine was developed and characterized. The linear range of the assay in this ELISA method was extended from 1.56 to 25 mug ml(-1) possessing the detection limit of 1.56 mug ml(-1). The established ELISA using MAb 2A1-9E-1 was applied for the survey of isoquinoline alkaloids in various medicinal plants.

Ginsenosides from American ginseng: chemical and pharmacological diversity

Ginseng occupies a prominent position in the list of best-selling natural products in the world. Compared to the long history of use and widespread research on Asian ginseng, the study of American ginseng is relatively limited. In the past decade, some promising advances have been achieved in understanding the chemistry, pharmacology and structure-function relationship of American ginseng. To date, there is no systematic review of American ginseng. In this review, the different structures of the ginsenosides in American ginseng are described, including naturally occurring compounds and those resulting from steaming or biotransformation. Preclinical and clinical studies published in the past decade are also discussed. Highlighted are the chemical and pharmacological diversity and potential structural-activity relationship of ginsenosides. The goal is that this article is a useful reference to chemists and biologists researching American ginseng, and will open the door to agents in drug discovery.

Letter to the editor: Panaxadiol's anticancer activity is enhanced by epicatechin

We previously reported the antiproliferative effect of panaxadiol (PD), an active compound in steamed ginseng, on human HCT-116 colorectal cancer cells, and that antioxidants might play a role in this effect. In this study, we observed that PD's antiproliferative effect was significantly enhanced by epicatechin (EC), a strong natural antioxidant in grape seed. Evidence for the synergistic antiproliferative effect was supported by the remarkable increase in the number of apoptotic cells.

Abstract 5435: The potential of ginseng for cancer chemoprevention

The clinical management of cancer invariably involves diverse conventional modalities, including surgery, radiation, and chemotherapy. However, the complexity of human cancer requires some alternative management to improve the therapeutic efficacy of conventional treatment and/or the quality of life of cancer patients. Medicinal botanicals have recently gained more attention for cancer management. Numerous effective anticancer drugs have been developed from botanicals, and identifying new herbal sources to develop ideal chemoprevention remains an essential step in advancing the treatment of colorectal cancer. In this study, potential roles of ginseng herbs, especially American ginseng and notoginseng, in cancer chemoprevention are evaluated. The major pharmacologically active constituents of ginsengs are ginsenosides, which can be mainly classified into protopanaxadiol and protopanaxatriol groups. The recognized active anticancer compounds from American ginseng and notoginseng are ginsenosides Rg3, Rh2, and protopanaxadiol. The structure-activity relationship between their chemical structures and pharmacological activities is discussed. Sugar molecules within a ginsenoside have a high impact on cancer cells. Anticancer activities increase with the decrease of sugar number. In addition, we observed that various steaming temperatures and time treatments of the ginseng herbs can change their ginsenoside profiles and enhance their anticancer activities. This heat treatment process may increase the efficacy of ginseng in cancer chemoprevention. (This work was supported in part by the NIH/NCCAM grants AT003255, AT004418 and AT005362).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5435. doi:10.1158/1538-7445.AM2011-5435

Red notoginseng: higher ginsenoside content and stronger anticancer potential than Asian and American ginseng

A systematic comparison of the ginsenosides and anticancer activities was performed among white (air-dried) and red (steamed) roots of notoginseng (NG, Panax notoginseng), Asian ginseng (AG, P. ginseng), and American ginseng (AmG, P. quinquefolius). Chemical profiles of different ginseng species were characterized, through simultaneous quantification of nineteen major ginsenosides, by HPLC-UV at 202 nm. The antiproliferative and pro-apoptotic effects on human colorectal cancer cells were determined by MTS method and flow cytometry, respectively. Chemical analysis indicated that white NG possessed the most abundant ginsenosides, i.e., two- and five-fold higher than white AmG and AG. During the steaming process, extensive conversion of the original polar ginsenosides in white ginseng to new, less polar, degradation compounds in red ginseng was observed. White ginsengs produced weak antiproliferative effects, while red ginsengs exhibited a significant increase in antiproliferative and pro-apoptotic effects (both P < 0.01 vs. white ginseng). Among the three red ginsengs, red NG showed the best anticancer activity. Due to the low cost of NG and high bioactivity of red NG, the red NG is promising to be a useful botanical product in cancer chemoprevention.

Effects of Triterpenoid Glycosides from Fresh Ginseng Berry on SW480 Human Colorectal Cancer Cell Line

Purpose

The pharmacological activities, notably the anticancer properties, of bioactive constituents fromfresh American ginseng berry have not yet been well studied. In this study, we investigated the antiproliferative effects of fresh American ginseng berry extract (AGBE) and its representative triterpenoid glycosides using the human colorectal cancer cell line SW480.

Materials and Methods

Using high performance liquid chromatography (HPLC), the contents of 8 ginsenosides in AGBE were determined. The cell growth inhibitory effects of AGBE and three triterpenoid glycosides (ginsenosides Rb3, Re, and Rg3) were evaluated by proliferation assay and ³H-thymidine incorporation assay. Cell cycle and apoptotic effects were analyzed by using flow cytometry after staining with propidium iodide and annexin V.

Results

HPLC analysis data showed that AGBE has a distinct ginsenoside profile. AGBE inhibited SW480 cell growth significantly in a time-dependent (24-96 hours) and concentration-dependent (0.1-1.0 mg/mL) manner. Ginsenosides Rb3, Re, and Rg3 also possess significant antiproliferative activities on SW480 cells. ³H-thymidine incorporation assay indicated that AGBE and ginsenosides Rb3, Re, and Rg3 might inhibit the transferring and duplication of DNA in SW480 cells. Flow cytometric assay data suggested that AGBE arrested SW480 cells in S and G2/M phases, and significantly induced cell apoptosis.

Conclusion

AGBE and ginsenosides Rb3, Re, and Rg3 possessed significant antiproliferative effects and induced changes of morphological appearance on SW480 cells. The mechanisms of the antiproliferation of AGBE and tested ginsenosides involved could be cell cycle arrest and induction of apoptosis.

Isolation and analysis of ginseng: advances and challenges

Ginseng occupies a prominent position in the list of best-selling natural products in the world. Because of its complex constituents, multidisciplinary techniques are needed to validate the analytical methods that support ginseng's use worldwide. In the past decade, rapid development of technology has advanced many aspects of ginseng research. The aim of this review is to illustrate the recent advances in the isolation and analysis of ginseng, and to highlight new applications and challenges. Emphasis is placed on recent trends and emerging techniques.

Ginsenoside Rh2 induces apoptosis and paraptosis-like cell death in colorectal cancer cells through activation of p53

Ginsenosides are the main bioactive components in American ginseng, a commonly used herb. In this study, we showed that the ginsenoside Rh2 exhibited significantly more potent cell death activity than the ginsenoside Rg3 in HCT116 and SW480 colorectal cancer cells. Cell death induced by Rh2 is mediated in part by the caspase-dependent apoptosis and in part by the caspase-independent paraptosis, a type of cell death that is characterized by the accumulation of cytoplasmic vacuoles. Treatment of cells with Rh2 activated the p53 pathway and significantly increased the levels of the pro-apoptotic regulator, Bax, while decreasing the levels of anti-apoptosis regulator Bcl-2. Removal of p53 significantly blocked Rh2-induced cell death as well as vacuole formation, suggesting that both types of cell death induced by Rh2 are mediated by p53 activity. Furthermore, we show that Rh2 increased ROS levels and activated the NF-κB survival pathway. Blockage of ROS by NAC or catalase inhibited the activation of NF-κB signaling and enhanced Rh2-induced cell death, suggesting that the anti-cancer effect of Rh2 can be enhanced by antioxidants.

Ginsenoside Rg3 inhibits colorectal tumor growth through the down-regulation of Wnt/ß-catenin signaling

Colorectal cancer (CRC) is one of the most common and deadly malignancies in the world. Most CRCs are initiated by aberrant activation of the Wnt/ß-catenin signaling pathway. Despite the advances in its early diagnosis, optimized surgical approaches, and chemotherapies, the clinical management of advanced CRC requires effective adjuvant agents. Ginsenoside Rg3 is a single compound isolated from American ginseng (Panax quinquefolius L., Araliaceae) and Asian ginseng (Panax ginseng C. A. Meyer). We investigated the anticancer activity of Rg3 on colon cancer cells and its potential molecular mechanism behind Rg3's anticancer activity. We found that Rg3 inhibits cell proliferation and viability of cancer cells in vitro. This inhibitory effect of Rg3 is, at least in part, mediated by blocking nuclear translocation of the ß-catenin protein and hence inhibiting ß-catenin/Tcf transcriptional activity. Allelic deletion of the oncogenic ß-catenin in HCT116 cells renders the cells more sensitive to Rg3-induced growth inhibition. Using the xenograft tumor model of human colon cancer, we have demonstrated that Rg3 effectively inhibits the growth of tumors derived from the human colon cancer cell line HCT116. Histologic examination revealed that Rg3 inhibits cancer cell proliferation, decreases PNCA expression and diminishes nuclear staining intensity of ß-catenin. Taken together, our results strongly suggest that the anticancer activity of Rg3 may be in part caused by blocking the nuclear translocation of ß-catenin in colon cancer cells. This line of investigation may lead to the development of novel therapies in which Rg3 can be used as an effective adjuvant agent for the clinical management of colorectal cancers.

Abstract B69: Potential cancer chemopreventive compounds from Oplopanax horridus, a native North American plant

Distributed throughout the west of North America, the plant Oplopanax horridus, or devil's club, belongs to the genus Oplopanax, which consists of three species (O. elatus, O. japonicus and O. horridus). Although many studies on the other two species have been performed, phytochemical and pharmacological investigations on O. horridus have been limited, especially cancer chemopreventive studies. After comparing differences of antiproliferative potentials among different plant parts of O. horridus, the root bark was selected to perform further phytochemical isolation to prepare active anticancer fractionations and compounds. The hydrophobic fractions showed potent antiproliferative effects on human HCT-116 and SW-480 colorectal cancer cells. Subsequent isolation of the hydrophobic fractions gave six polyynes and one polyene; in which two novel compounds, Oplopantriol A and Oplopantriol B, were obtained and their absolute structures were elucidated by detailed spectroscopic analyses, including 1D and 2D NMR techniques and chemical methods. The content of these seven compounds in the O. horridus root bark was determined using an on-line SPE-HPLC method. Pharmacological studies showed that two polyynes, including a novel compound (Oplopantriol A), possessed strong cancer cell inhibitory activities (P &lt; 0.001). The IC50 of these two polyynes were observed at 1-5 µM on the colorectal cancer cells. Treatment with active fraction and compounds noticeably induced apoptosis, and distinctly induced the G2/M phase arrest of the cell cycle in a time- and concentration-dependent manner. The trend of increasing cyclin A and cyclin B1 were similar to the increase of G2/M phase cells in all treated groups. These results suggested that active O. horridus fraction and selected polyynes had potential antiproliferative activities on human colorectal cancer cells. The observed cancer chemopreventive effects could be related to the induction of apoptosis and regulation of cell cycle transition. (This work was supported in part by the NIH/NCCAM grants AT003255, AT004418 and AT005362).

Citation Information: Cancer Prev Res 2010;3(12 Suppl):B69.

Hydrophobic constituents and their potential anticancer activities from Devil's Club (Oplopanax horridus Miq.)

ETHNOPHARMACOLOGICAL RELEVANCE

Devil's Club (Oplopanax horridus) is one of the most important spiritual and medicinal plants to many indigenous peoples of Alaska and the Pacific Northwest. It is widely used for external and internal infections as well as arthritis, respiratory ailments, digestive tract ailments, broken bones, fever, headaches, and cancer.

AIM OF THE STUDY

To investigate hydrophobic constituents and their potential anticancer activity from Devil's Club, Oplopanax horridus.

MATERIALS AND METHODS

The root bark extract of Oplopanax horridus was isolated by chromatographic techniques. Structures of isolated compounds were identified by spectroscopic methods and comparison with published data. The anti-proliferation of isolated hydrophobic constituents in human breast cancer MCF-7 cells, human colon cancer SW-480 and HCT-116 cells were tested. The potential mechanism of anti-proliferation was also investigated using cell cycle and apoptosis assays.

RESULTS AND DISCUSSION

Six compounds were isolated and structurally identified as 9,17-octadecadiene-12,14-diyne-1,11,16-triol, 1-acetate (1), oplopandiol acetate (2), falcarindiol (3), oplopandiol (4), trans-nerolidol (5) and t-cadinol (6). These compounds showed potential anticancer activities on human breast cancer and colon cancer cells, of which compound 3 possesses the strongest activity. Further cell cycle and apoptosis tests by flow cytometry showed the polyacetylenes 1-4 induced HCT-116 cell arresting in G2/M phase and inhibited proliferation by the induction of apoptosis at both earlier and later stages.

CONCLUSION

These results provide promising baseline information for the potential use of Oplopanax horridus, as well as some of the isolated compounds in the treatment of cancer.

Improving anticancer activities of Oplopanax horridus root bark extract by removing water-soluble components

O. horridus is used as a folk medicine by natives in the Northern Pacific coast of North America. This experiment studied the antiproliferative effects of the extract of O. horridus root bark and its fractions chromatographed from Dianion HP20 resin column with water, 30, 50, 70 and 100% ethanol on human breast cancer MCF-7 cells and non-small cell lung cancer (NSCLC) cells. The role of O. horridus in the cell cycle and apoptosis of MCF-7 cells was also investigated. The results showed that the 70% and 100% ethanol fractions demonstrated more potent antiproliferative effects than the total extract on both cell lines. The antiproliferative effects may result from the enrichment of active constituents detected by high performance liquid chromatography (HPLC). The IC(50) of the total extract, 50, 70, and 100% ethanol fractions for antiproliferation on MCF-7 cells were 248.4, 123.1, 44.0, and 31.5 microg/mL, respectively, and on NSCLC cells were 125.3, 271.1, 17.6, and 23.2 microg/mL, respectively. On the other hand, the water and 30% ethanol fractions significantly promoted cell proliferation on MCF-7 cells at concentrations > 100 microg/mL, suggesting that the hydrophilic fractions should be removed from the extract when used for cancer chemoprevention in order to achieve desirable activities. The effects of the total extract on cell cycle and apoptosis were similar to that of the 100% ethanol fraction because of the similarity of their chemical composition. At higher concentrations, the apoptotic effects of the 70% ethanol fraction are more significant. Data from this study suggested that the 70% and 100% ethanol fractions are active antiproliferative fractions and that induction of apoptosis is the mechanism involved in the antiproliferative effect observed.

American ginseng: potential structure-function relationship in cancer chemoprevention

Ginseng has a prominent position on the list of best-selling herbal products in the world, and its main active constituents are thought to be ginsenosides. Compared with the long history of use and widespread research on Asian ginseng, studies of American ginseng are relatively limited, especially regarding cancer chemoprevention. In recent studies of American ginseng, steaming or heating altered the ginsenoside profile and thereby increased anticancer effects. Yet the ginsenoside structures and their activities have not been systematically elucidated. In this commentary, we introduce the different ginsenosides in American ginseng, both the naturally occurring compounds and those resulting from steaming or biotransformation. We briefly review American ginseng's reported anticancer effects and their mechanisms of action, and explore the possible structural-function relationship with a focus on sugar molecules, hydroxyl groups and stereoselectivity in ginsenosides. Understanding these relationships may produce insights into chemical and pharmacological approaches for enhancing the chemopreventive effects of ginsenoside and for developing novel anticancer agents.

In vitro and in vivo anticancer effects of American ginseng berry: exploring representative compounds

Panax ginseng roots, including the steamed roots, have been demonstrated to possess anticancer properties. However, there have been limited published studies on the cancer preventive effects of American ginseng. In this study, the in vitro and in vivo anti-colorectal cancer effects of American ginseng berry extracts, and their representative bioactive compounds were evaluated. The ginsenoside content in unsteamed American ginseng berry extract (AGE) and steamed berry extract (S-AGE) were determined by HPLC. In comparison to AGE, S-AGE showed significantly stronger antiproliferative effects on HCT-116, SW-480 and HT-29 human colorectal cancer cells. Antiproliferative effects of representative constituents in AGE and S-AGE, ginsenosides Rb3 and Rg3, were also evaluated, showing that Rg3 had a positive effect. Using flow cytometric analyses, we found that S-AGE arrests cancer cells in G1-phase and significantly induces cell apoptosis. Using xenograft mice, we conducted an in vivo antitumor study using S-AGE after HCT-116 cell inoculation. We observed that 50 mg/kg of S-AGE showed significant antitumor effects. Our results suggested that S-AGE inhibited the colorectal cancer growth both in vitro and in vivo, and this inhibition might be achieved through cell cycle arrest and induced apoptosis in the cells.

High performance liquid chromatographic analysis and anticancer potential of Oplopanax horridus: comparison of stem and berry extracts

Oplopanax horridus or devil's club is a herbal medicine distributed in North America. The constituents and pharmacological activities of O. horridus (OPH) are largely unknown. In this study, we assayed OPH stem and berry extracts using high performance liquid chromatography (HPLC). The anticancer potentials of extracts on different human cancer cell lines (SW-480, HCT-116, HT-29, MCF-7 and NSCLC) were determined by MTS method. The effect of stem extract on cancer cell cycle, expression of cyclin A, and apoptosis were assayed using flow cytometry. HPLC data showed that the composition of OPH stem extract is more complicated than the berry extract. The wavelength of maximum absorption of the major constituent in stem and berry is 196.0 nm and 201.9 nm, respectively. Compared to the berry extract, the stem extract showed significant potent antiproliferative effect on all the studied cell lines. The stem extract at 0.1 mg/ml arrested cancer cells in S- and G2/M-phases, and significantly induced expression of cyclin A. After treatment with 0.1 mg/ml of stem extract for 72 h, apoptotic cells were increased to 45.2%, while control was 9.6%. The cell cycle arrest and induction of apoptosis may play a critical role in cancer chemoprevention by Oplopanax horridus stem extract.

Isolation and identification of two new polyynes from a North American ethnic medicinal plant--Oplopanax horridus (Smith) Miq

Two new polyynes, named oplopantriol A (5) and oplopantriol B (6), were isolated from the root bark of Oplopanax horridus (Smith) Miq, an ethnic medicinal plant of North America, along with four known polyynes: (3S,8S)-falcarindiol (1), oplopandiol (2), (11S,16S,9Z)-9,17-octadecadiene-12,14-diyne-1,11,16-triol, 1-acetate (3) and oplopandiol acetate (4). The structures of the new compounds were elucidated by detailed spectroscopic analyses, including 1D and 2D NMR techniques and chemical methods. The absolute configurations of the new compounds 5 and 6 were determined by comparing their optical rotation values with the hydrolysis products of the known compounds 3 and 4, respectively, derived from the same plant. On the basis of an analysis of their physical and chemical properties we show that the alkaline hydrolysis of 3 and 4 afforded the new compounds 5 and 6, respectively.

Effects of Oplopanax horridus on human colorectal cancer cells

AIM

In this study, we investigated the inhibitive effects of Oplopanax horridus extract (OhE) and its fractions (OhF1, OhF2, OhF3, OhF4 and OhF5) on the growth of human colorectal cancer cells and the possible mechanisms involved were investigated.

MATERIALS AND METHODS

The antiproliferative effects were evaluated by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) cell proliferation assay. Apoptotic effects and cell cycle distribution were analyzed by flow cytometry after staining with Annexin V/PI or PI/RNase.

RESULTS

After treatment for 48 h, OhE, OhF4 and OhF5 (10-100 microg/ml) inhibited proliferation of HCT-116, SW-480 and HT-29 cell lines, and cell growth decreased most with the treatment of OhF4. On the other hand, OhF1, OhF2 and OhF3 were not observed to have obvious suppressive effects on these cell lines at concentrations of 10-100 microg/ml. OhE, OhF4 and OhF5 (1-10 microg/ml) noticeably induced apoptosis time- and concentration-dependently compared to the control at the same time point. Treatment with OhE, OhF4 or OhF5 (1-10 microg/ml) for 24 h distinctly induced a G(2)/M-phase arrest of the cell cycle in a dose-dependent manner. The trend of increasing cyclin A and cyclin B1 were similar to the increase of G(2)/M phase cells in all treated groups.

CONCLUSION

These results showed that OhE had potential antiproliferative effects on human colorectal cancer cells, and the active components are enriched in the OhF4 and OhF5 fractions. The anticancer mechanism of OhE, OhF4 and OhF5 might be attributed to the induction of apoptosis and the regulation of cell cycle transition.