Chunhao Yu

Epigallocatechin Gallate (EGCG) Is the Most Effective Cancer Chemopreventive Polyphenol in Green Tea

Green tea is a popular drink consumed daily by millions of people around the world. Previous studies have shown that some polyphenol compounds from green tea possess anticancer activities. However, systemic evaluation was limited. In this study, we determined the cancer chemopreventive potentials of 10 representative polyphenols (caffeic acid, CA; gallic acid, GA; catechin, C; epicatechin, EC; gallocatechin, GC; catechin gallate, CG; gallocatechin gallate, GCG; epicatechin gallate, ECG; epigallocatechin, EGC; and epigallocatechin gallate, EGCG), and explored their structure-activity relationship. The effect of the 10 polyphenol compounds on the proliferation of HCT-116 and SW-480 human colorectal cancer cells was evaluated using an MTS assay. Cell cycle distribution and apoptotic effects were analyzed by flow cytometry after staining with propidium iodide (PI)/RNase or annexin V/PI. Among the 10 polyphenols, EGCG showed the most potent antiproliferative effects, and significantly induced cell cycle arrest in the G1 phase and cell apoptosis. When the relationship between chemical structure and anticancer activity was examined, C and EC did not show antiproliferative effects, and GA showed some antiproliferative effects. When C and EC esterified with GA to produce CG and ECG, the antiproliferative effects were increased significantly. A similar relationship was found between EGC and EGCG. The gallic acid group significantly enhanced catechin’s anticancer potential. This property could be utilized in future semi-synthesis of flavonoid derivatives to develop novel anticancer agents.

Hydrophobic flavonoids from Scutellaria baicalensis induce colorectal cancer cell apoptosis through a mitochondrial-mediated pathway

Scutellaria baicalensis extract (SbE) has been shown to exert chemopreventive effects on several types of cancer. Baicalin, a hydrophilic flavonoid found in SbE, may have opposing effects that decrease the antitumor potential of SbE against colorectal cancer. In this study, after removing baicalin, we prepared an aglycone-rich fraction (ARF) of SbE and evaluated its anti-proliferative activity and mechanisms of action. The flavonoids found in ARF, baicalin fraction (BF) and SbE were determined by high-performance liquid chromatography (HPLC). The effects of ARF, BF, SbE and representative flavonoids on the proliferation of HCT-116 and HT-29 human colorectal cancer cells were determined by an MTS assay. The cell cycle, the expression of cyclins A and B1 and cell apoptosis were assayed using flow cytometry. Apoptosis-related gene expression was visualized by quantitative real-time polymerase chain reaction (PCR), and mitochondrial membrane potential was estimated following staining with JC-1. HPLC analysis showed that ARF contained two hydrophobic flavonoids, baicalein and wogonin, and that BF contained only baicalin. SbE had little anti-proliferative effect on the colorectal cancer cells; cancer cell growth was even observed at certain concentrations. ARF exerted potent anti-proliferative effects on the cancer cells. By contrast, BF increased cancer cell growth. ARF arrested cells in the S and G2/M phases, increased the expression of cyclins A and B1, and significantly induced cell apoptosis. Multiple genes in the mitochondrial pathway are involved in ARF-induced apoptosis, and subsequent cellular functional analysis validated the involvement of this pathway. These results suggest that removing baicalin from SbE produces an ARF that significantly inhibits the growth of colorectal cancer cells, and that the mitochondrial apoptotic pathway plays a role in hydrophobic flavonoid-induced apoptosis.

Chinese herbal medicine Tianqi reduces progression from impaired glucose tolerance to diabetes: a double-blind, randomized, placebo-controlled, multicenter trial.

CONTEXT Living in a prediabetes state significantly increases a patients risk for both diabetes and cardiovascular disease. Tianqi capsule, containing 10 Chinese herbal medicines, is used in China for the treatment of type 2 diabetes mellitus (T2DM). OBJECTIVE The purpose of this study was to assess whether Tianqi prevented T2DM in subjects with impaired glucose tolerance (IGT) over the course of a 12-month treatment. METHODS Individuals with IGT were randomly allocated in a double-blind manner to receive Tianqi (n = 210) or a placebo (n = 210) for 12 months. Oral glucose tolerance tests were conducted every 3 months to assess the development of diabetes or restoration to normal glucose tolerance. All subjects received the same lifestyle education. The primary endpoint was the conversion of IGT to T2DM. Body weight and body mass index were observed. Adverse effects were monitored. RESULTS Of the 420 enrolled subjects with IGT, 389 completed the trial (198 in the Tianqi group and 191 in the placebo group). At the end of the 12-month trial, 36 subjects in the Tianqi group (18.18%) and 56 in the placebo group (29.32%) had developed diabetes (P = .01). There was a significant difference in the number of subjects who had normal glucose tolerance at the end of the study between the Tianqi and placebo groups (n = 125, 63.13%, and n = 89, 46.60%, respectively; P = .001). Coxs proportional hazards model analysis showed that Tianqi reduced the risk of diabetes by 32.1% compared with the placebo. No severe adverse events occurred in the trial. There were no statistical differences in body weight and body mass index changes between the Tianqi group and the placebo group during the 12-month trial. CONCLUSIONS Treatment with a Tianqi capsule for 12 months significantly decreased the incidence of T2DM in subjects with IGT, and this herbal drug was safe to use.

Salvia miltiorrhiza (Dan Shen) Significantly Ameliorates Colon Inflammation in Dextran Sulfate Sodium Induced Colitis

Inflammatory bowel disease increases the risks of human colorectal cancer. In this study, the effects of Salvia miltiorrhiza extract (SME) on chemically-induced colitis in a mouse model were evaluated. Chemical composition of SME was determined by HPLC analysis. A/J mice received a single injection of AOM 7.5 mg/kg. After one week, these mice received 2.5% DSS for eight days, or DSS plus SME (25 or 50 mg/kg). DSS-induced colitis was scored with the disease activity index (DAI). Body weight and colon length were also measured. The severity of inflammatory lesions was further evaluated by colon tissue histological assessment. HPLC assay showed that the major constituents in the tested SME were danshensu, protocatechuic aldehyde, salvianolic acid D, and salvianolic acid B. In the model group, the DAI score reached its highest level on Day 8, while the SME group on both doses showed a significantly reduced DAI score (both p < 0.01). As an objective index of the severity of inflammation, colon length was significantly shorter in the model group than the vehicle group. Treatment with 25 and 50 mg/kg of SME inhibited the shortening of colon in a dose-related manner (p < 0.05 and p < 0.01, respectively). SME groups also significantly reduced weight reduction (p < 0.05). Colitis histological data supported the pharmacological observations. Thus, Salvia miltiorrhiza could be a promising candidate in preventing and treating colitis and in reducing the risks of inflammation-associated colorectal cancer.

Pretreatment of baicalin and wogonoside with glycoside hydrolase: A promising approach to enhance anticancer potential

Previous phytochemical studies showed that the major flavonoids in Scutellaria baicalensis are baicalin, baicalein, wogonoside and wogonin. The two glycosides (baicalin and wogonoside) can be transformed into their aglycons (baicalein and wogonin), which possess positive anticancer potential. In this study, we used glycosidase to catalyze flavonoids in S. baicalensis to enhance the herb’s anticancer activities. Our HPLC data showed that, using the optimized conditions obtained in our experiments (20 U/g of cellulase, 50ºC, pH 4.8 and treatment for 8 h), there was a marked transformation from the two glycosides to their aglycons. The anticancer activity was subsequently evaluated using a series of S. baicalensis extracts in which variable lengths of glycosidase treatment time were used. Combining analytical and bioassay results, we observed that the higher the aglycon content, the stronger the antiproliferation effects. Compared to the untransformed control, 8 h of glycosidase catalyzing significantly increased antiproliferative activity on human colorectal and breast cancer cells, and its cancer cell growth inhibition is, in part, mediated by cell cycle arrest at the S-phase and induction of apoptosis. Data from this study suggest that using glycosidase to catalyze S. baicalensis offers a promising approach to increase its anticancer activity.

Identification of potential anticancer compounds from Oplopanax horridus

Oplopanax horridus is a plant native to North America. Previous reports have demonstrated that this herb has antiproliferative effects on cancer cells but study mostly focused on its extract or fractions. Because there has been limited phytochemical study on this herb, its bioactive compounds are largely unknown. We recently isolated and identified 13 compounds, including six polyynes, three sesquiterpenes, two steroids, and two phenolic acids, of which five are novel compounds. In this study, we systemically evaluated the anticancer effects of compounds isolated from O. horridus. Their antiproliferative effects on a panel of human colorectal and breast cancer cells were determined using the MTS assay. Cell cycle distribution and apoptotic effects were analyzed by flow cytometry. The in vivo antitumor effect was examined using a xenograft tumor model. Among the 13 compounds, strong antiproliferative effects were observed from falcarindiol and a novel compound oplopantriol A. Falcarindiol showed the most potent antiproliferative effects, significantly inducing pro-apoptosis and cell cycle arrest in the S and G2/M phases. The anticancer potential of falcarindiol was further verified in vivo, significantly inhibiting HCT-116 tumor growth in an athymic nude mouse model at 15 mg/kg. We also analyzed the relationship between polyyne structures and their pharmacological activities. We observed that both the terminal hydroxyl group and double bond obviously affected their anticancer potential. Results from this study supplied valuable information for future semi-synthesis of polyyne derivatives to develop novel cancer chemopreventive agents.

Adulteration and cultivation region identification of American ginseng using HPLC coupled with multivariate analysis.

American ginseng (Panax quinquefolius) is originally grown in North America. Due to price difference and supply shortage, American ginseng recently has been cultivated in northern China. Further, in the market, some Asian ginsengs are labeled as American ginseng. In this study, forty-three American ginseng samples cultivated in the USA, Canada or China were collected and 14 ginseng saponins were determined using HPLC. HPLC coupled with hierarchical cluster analysis and principal component analysis was developed to identify the species. Subsequently, an HPLC-linear discriminant analysis was established to discriminate cultivation regions of American ginseng. This method was successfully applied to identify the sources of 6 commercial American ginseng samples. Two of them were identified as Asian ginseng, while 4 others were identified as American ginseng, which were cultivated in the USA (3) and China (1). Our newly developed method can be used to identify American ginseng with different cultivation regions.

Paraptosis and NF-κB activation are associated with protopanaxadiol-induced cancer chemoprevention

BackgroundProtopanaxadiol (PPD) is a triterpenoid that can be prepared from steamed ginseng. PPD possesses anticancer potential via caspase-dependent apoptosis. Whether paraptosis, a type of the caspase-independent cell death, is also induced by PPD has not been evaluated.MethodsCell death, the cell cycle and intracellular reactive oxygen species (ROS) were analyzed by flow cytometry after staining with annexin V/PI, PI/RNase or H2DCFDA. We observed morphological changes by crystal violet staining assay. Mitochondrial swelling was measured by ultraviolet–visible spectrophotometry. The activation of NF-κB was measured by luciferase reporter assay.ResultsAt comparable concentrations of 5-fluorouracil, PPD induced more cell death in human colorectal cancer cell lines HCT-116 and SW-480. We demonstrated that PPD induced paraptosis in these cancer cells. PPD treatment significantly increased the percentage of cancer cells with cytoplasmic vacuoles. After the cells were treated with PPD and cycloheximides, cytoplasmic vacuole generation was inhibited. The paraptotic induction effect of PPD was also supported by the results of the mitochondrial swelling assay. PPD induced ROS production in cancer cells, which activated the NF-κB pathway. Blockage of ROS by NAC or PS-1145 inhibited the activation of NF-κB signaling.ConclusionsPPD induces colorectal cancer cell death in part by induction of paraptosis. The anticancer activity of PPD may be enhanced by antioxidants such as green tea, which also inhibit the activation of NF-κB signaling.

Protopanaxadiol, an active ginseng metabolite, significantly enhances the effects of fluorouracil on colon cancer.

In this study, we evaluated the effects of protopanaxadiol (PPD), a gut microbiome induced ginseng metabolite, in increasing the anticancer effects of a chemotherapeutic agent fluorouracil (5-FU) on colorectal cancer. An in vitro HCT-116 colorectal cancer cell proliferation test was conducted to observe the effects of PPD, 5-FU and their co-administration and the related mechanisms of action. Then, an in vivo xenografted athymic mouse model was used to confirm the in vitro data. Our results showed that the human gut microbiome converted ginsenoside compound K to PPD as a metabolite. PPD and 5-FU significantly inhibited HCT-116 cell proliferation in a concentration-dependent manner (both p < 0.01), and the effects of 5-FU were very significantly enhanced by combined treatment with PPD (p < 0.01). Cell cycle evaluation demonstrated that 5-FU markedly induced the cancer cell S phase arrest, while PPD increased arrest in G1 phase. Compared to the control, 5-FU and PPD increased apoptosis, and their co-administration significantly increased the number of apoptotic cells (p < 0.01). Using bioluminescence imaging, in vivo data revealed that 5-FU significantly reduced the tumor growth up to Day 20 (p < 0.05). PPD and 5-FU co-administration very significantly reduced the tumor size in a dose-related manner (p < 0.01 compared to the 5-FU alone). The quantification of the tumor size and weight changes for 43 days supported the in vivo imaging data. Our results demonstrated that the co-administration of PPD and 5-FU significantly inhibited the tumor growth, indicating that PPD significantly enhanced the anticancer action of 5-FU, a commonly used chemotherapeutic agent. PPD may have a clinical value in 5-FU’s cancer therapeutics.

Antioxidant effects of Genkwa flos flavonoids on Freund׳s adjuvant-induced rheumatoid arthritis in rats.

ETHNOPHARMACOLOGICAL RELEVANCE Genkwa flos (Daphne genkwa Sieb. et Zucc.), a Chinese herbal medicine, has been traditionally used for over two thousand years in China for inflammation related symptoms, including joint pain. To evaluate the antioxidative effects of flavonoid aglycones (FA) isolated from Genkwa flos on adjuvant arthritis in rats and to identify the relationship between antioxidant potential and whole blood viscosity (WBV). MATERIALS AND METHODS FA compounds were identified using LC-MS and the content was assayed by HPLC. Arthritis was induced by an intradermal injection of Freund׳s complete adjuvant in the footpad. The effects of FA on paw volumes, secondary arthritis scores, histopathology of joints, and body and organ weights were measured. The antioxidant effects of FA and WBV were determined. RESULTS LC-MS analysis showed that the FA contained four major compounds: luteolin, apigenin, hydroxygenkwanin and genkwanin. FA significantly decreased paw edema, arthritis scores, and weight loss. These observations were consistent with the reduction of oxidative stress and the improvement of the WBV. CONCLUSION FA significantly decreased arthritis in a rat model through antioxidant and hemorheological modulatory mechanisms. The Genkwa flos flavonoids may have clinical potential for the treatment of rheumatoid arthritis.