[Applications of ion chromatography for the analysis of Chinese herbal medicine components].

Ion chromatography (IC) is a novel high performance liquid chromatographic technique that is suitable for the separation and analysis of ionic substances in different matrix samples. Since 1975, it has been widely used in many fields, such as the environment, energy, food, and medicine. IC compensates for the separation limitations of traditional gas chromatography and high performance liquid chromatography and can realize the qualitative analysis and quantitative detection of strongly polar components. This chromatographic technique features not only simple operations but also rapid analysis. The sensors used in IC are characterized by high sensitivity and selectivity, and the technique can simultaneously separate and determine multiple components. Several advances in IC instrumentation and chromatographic theories have been developed in recent years. IC can analyze various types of samples, including ions, sugars, amino acids, and organic acids (bases). Chinese herbal medicines are typically characterized by highly complex chemical compositions and may contain carbohydrates, proteins, alkaloids, and other active components. They also contain toxic residues such as sulfur dioxide, which may be produced during the processing of medicinal materials. Therefore, the analysis and elucidation of the precise chemical constituents of Chinese herbal medicines present key problems that must be resolved in modern Chinese herbal medicine research. In this context, IC has become an important method for analyzing and identifying the complex components of Chinese herbal medicines because this method is suitable for detecting a single active ingredients among complex components. This paper introduces the different types and principles of IC as well as research progress in this technique. As the applications of IC-based methods in pharmaceutical science, cell biology, and microbiology increase, further development is necessary to expand the applications of this technique. The development of innovative techniques has enabled IC technologies to achieve higher analytical sensitivity, better selectivity, and wider application. The components of Chinese herbal medicines can be divided into endogenous and exogenous components according to their source: endogenous components include glycosides, amino acids, and organic acids, while exogenous components include toxic residues such as sulfur dioxide. Next, the applications of IC to the complex components of Chinese herbal medicines in recent decades are summarized. The most commonly used IC technologies and methods include ion exchange chromatography and conductivity detection. The advantages of IC for the analysis of alkaloids have been demonstrated. This method exhibits better characteristics than traditional analytical methods. However, the applications of IC for the speciation analysis of inorganic anions are limited. Moreover, few reports on the direct application of the technique for the determination of the main active substances in Chinese herbal medicines, including flavonoids, phenylpropanoids, and steroids, have been reported. Finally, this paper reviews new IC technologies and their application progress in Chinese herbal medicine, focusing on their prospects for the effective separation and analysis of complex components. In particular, we discuss the available sample (on-line) pretreatment technologies and explore possible technologies for the selective and efficient enrichment and separation of different components. Next, we assess innovative research on solid-phase materials that can improve the separation effect and analytical sensitivity of IC. We also describe the features of multidimensional chromatography, which combines the advantages of various chromatographic techniques. This review provides a theoretical reference for the further development of IC technology for the analysis of the complex chemical components of Chinese herbal medicines.

Assay of selenol species in biological samples by the fluorescent probe Sel-green.

Selenium (Se) is an essential trace element for diverse cellular functions. The biological significance of Se is predominantly dependent on its incorporation into the selenocysteine (Sec) for synthesis of selenoproteins (SePs), such as thioredoxin reductase family enzymes and glutathione peroxidase family enzymes. In general, the hyperactivity of the selenol group in Sec confers the Sec residue critical for functions of SePs. The Sec is much less abundant than its sulfur analog cysteine (Cys), and it remains a high challenge to detect Sec, especially in complex biological samples. We recently reported a selective fluorescent probe Sel-green for selenols and summarized the principles for design of selenol (and thiophenol) probes. Sel-green discriminates selenols from other biological species, especially thiols, under physiological conditions, and has been applied to detect both endogenous and exogenous selenol species in live cells. In this chapter, we describe a protocol and guideline for the selective detection of Sec by applying the Sel-green. This protocol is also suitable for detection of other selenol species. This practical and convenient assay would assist scientists to better understand the pivotal roles of Sec as well as SePs.

Fusaricide is a Novel Iron Chelator that Induces Apoptosis through Activating Caspase-3.

Nonsmall cell lung cancer (NSCLC) has been a fatal and refractory disease worldwide. Novel therapeutic developments based on fundamental investigations of anticancer mechanisms underlie substantial foundations to win the fight against cancer diseases. In this study, we isolated a natural product fusaricide (FCD) from an endophytic fungus of Lycium barbarum, identified as Epicoccum sp. For the first time, we discovered that FCD potently inhibited proliferation in a variety of human NSCLC cell lines, with relatively less toxicity to normal cells. Our study exhibited that FCD induced apoptosis, caused DNA damage and cell cycle arrest in G0/G1 phase, and activated caspase-3 as well as other apoptosis-related factors in human NSCLC NCI-H460 cells. FCD was proven to be an iron chelator that actively decreased levels of cellular labile iron pool in NCI-H460 cells in our study. FeCl3 supplement reversed FCD-induced apoptosis. The upregulation of transferrin receptor 1 (TfR1) and downregulation of ferritin heavy chain (FTH) expression were observed after FCD treatment. In summary, our study highlighted the potential anticancer effects of FCD against human NSCLCs and demonstrated that the FCD-mediated apoptosis depended on binding to intracellular iron.

Combined administration on You-Gui Yin and low-dose Raloxifene partially attenuates the bone loss in ovariectomized mice through the proliferation and osteogenic differentiation of bone marrow stromal cells.

BACKGROUND: Osteoporosis is a systemic skeletal disease of fragility fractures due to the loss of mass and deterioration of the microarchitecture of bone. PURPOSE: The aim of the study was to assess the osteogenic effects and the underlying mechanisms of the combined administration of You-Gui Yin (YGY) and Raloxifene hydrochloride (RLX) in ovariectomized (OVX) mice. METHODS: First, a classic animal model was used to mimic postmenopausal osteoporosis through the removal of the ovary of mice. Second, the OVX mice were administered YGY, RLX, and YGY + RLX for 12 weeks. Next, the bone microtomographic histomorphometry and bone mineral density (BMD) were assessed by micro-CT, and the biochemical markers of procollagen type I N-terminal propeptide (P1NP) and beta-isomerized C-telopeptide (ß-CTX) in serum were assessed. Finally, primary bone marrow stromal cells (BMSCs) were isolated from the tibia and cultured to evaluate cell proliferation and osteogenic differentiation. RESULTS: The results showed that BMD on the YGY + RLX group was higher than that on the RLX group (p < 0.05) and did not have a significant difference when compared with the sham group. Notably, the YGY + RLX group had a dramatically increased trabecular number (Tb.N) compared with that of the YGY group (p < 0.05). Moreover, the BV/TV (bone volume/total volume) and Tb.N in the YGY + RLX group were higher than that in the RLX group (p < 0.05), and the Tb.Sp (trabecular separation) was lower than that in the RLX group (p < 0.05). Moreover, the serum level of P1NP from the YGY + RLX group dramatically increased when compared with that from the YGY and RLX groups (YGY group: p < 0.05; RLX groups: p < 0.01). Notably, there was no significant difference between the YGY and YGY + RLX groups. In addition, cell proliferation from the co-administration of YGY and RLX was clearly higher than a single use of YGY and RLX (p < 0.01, respectively). The ALP/BCA (alkaline phosphatase/bicinchoninic acid) in the YGY + RLX group was higher than that in the RLX group (p < 0.01). CONCLUSION: Overall, co-administered YGY and RLX could partially attenuate bone loss and were more effective than individually using either one; this outcome might be associated with the proliferation and osteogenic differentiation of BMSCs.

Xanthohumol, a polyphenol chalcone present in hops, activating Nrf2 enzymes to confer protection against oxidative damage in PC12 cells.

Xanthohumol (2',4',4-trihydroxy-6'-methoxy-3'-prenylchalcone, Xn), a polyphenol chalcone from hops (Humulus lupulus), has received increasing attention due to its multiple pharmacological activities. As an active component in beers, its presence has been suggested to be linked to the epidemiological observation of the beneficial effect of regular beer drinking. In this work, we synthesized Xn with a total yield of 5.0% in seven steps and studied its neuroprotective function against oxidative-stress-induced neuronal cell damage in the neuronlike rat pheochromocytoma cell line PC12. Xn displays moderate free-radical-scavenging capacity in vitro. More importantly, pretreatment of PC12 cells with Xn at submicromolar concentrations significantly upregulates a panel of phase II cytoprotective genes as well as the corresponding gene products, such as glutathione, heme oxygenase, NAD(P)H: quinone oxidoreductase, thioredoxin, and thioredoxin reductase. A mechanistic study indicates that the α,ß-unsaturated ketone structure in Xn and activation of the transcription factor Nrf2 are key determinants for the cytoprotection of Xn. Targeting the Nrf2 by Xn discloses a previously unrecognized mechanism underlying the biological action of Xn. Our results demonstrate that Xn is a novel small-molecule activator of Nrf2 in neuronal cells and suggest that Xn might be a potential candidate for the prevention of neurodegenerative disorders.

Shikonin targets cytosolic thioredoxin reductase to induce ROS-mediated apoptosis in human promyelocytic leukemia HL-60 cells.

Shikonin, a major active component of the Chinese herbal plant Lithospermum erythrorhizon, has been applied for centuries in traditional Chinese medicine. Although shikonin demonstrates potent anticancer efficacy in numerous types of human cancer cells, the cellular targets of shikonin have not been fully defined. We report here that shikonin may interact with the cytosolic thioredoxin reductase (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme with a C-terminal -Gly-Cys-Sec-Gly active site, to induce reactive oxygen species (ROS)-mediated apoptosis in human promyelocytic leukemia HL-60 cells. Shikonin primarily targets the Sec residue in TrxR1 to inhibit its physiological function, but further shifts the enzyme to an NADPH oxidase to generate superoxide anions, which leads to accumulation of ROS and collapse of the intracellular redox balance. Importantly, overexpression of functional TrxR1 attenuates the cytotoxicity of shikonin, whereas knockdown of TrxR1 sensitizes cells to shikonin treatment. Targeting TrxR1 with shikonin thus discloses a previously unrecognized mechanism underlying the biological activity of shikonin and provides an in-depth insight into the action of shikonin in the treatment of cancer.

Gambogic acid induces apoptosis in hepatocellular carcinoma SMMC-7721 cells by targeting cytosolic thioredoxin reductase.

The thioredoxin reductase (TrxR) isoenzymes, TrxR1 in cytosol or nucleus and TrxR2 in mitochondria, are essential mammalian selenocysteine (Sec)-containing flavoenzymes with a unique C-terminal -Gly-Cys-Sec-Gly active site. TrxRs are often overexpressed in a number of human tumors, and the reduction of their expression in malignant cells reverses tumor growth, making the enzymes attractive targets for anticancer drug development. Gambogic acid (GA), a natural product that has been used in traditional Chinese medicine for centuries, demonstrates potent anticancer activity in numerous types of human cancer cells and has entered phase II clinical trials. We discovered that GA may interact with TrxR1 to elicit oxidative stress and eventually induce apoptosis in human hepatocellular carcinoma SMMC-7721 cells. GA primarily targets the Sec residue in the antioxidant enzyme TrxR1 to inhibit its Trx-reduction activity, leading to accumulation of reactive oxygen species and collapse of the intracellular redox balance. Importantly, overexpression of functional TrxR1 in cells attenuates the cytotoxicity of GA, whereas knockdown of TrxR1 sensitizes cells to GA. Targeting of TrxR1 by GA thus discloses a previously unrecognized mechanism underlying the biological action of GA and provides useful information for further development of GA as a potential agent in the treatment of cancer.

Curcumin targeting the thioredoxin system elevates oxidative stress in HeLa cells.

The thioredoxin system, composed of thioredoxin reductase (TrxR), thioredoxin (Trx), and NADPH, is ubiquitous in all cells and involved in many redox-dependent signaling pathways. Curcumin, a naturally occurring pigment that gives a specific yellow color in curry food, is consumed in normal diet up to 100mg per day. This molecule has also been used in traditional medicine for the treatment of a variety of diseases. Curcumin has numerous biological functions, and many of these functions are related to induction of oxidative stress. However, how curcumin elicits oxidative stress in cells is unclear. Our previous work has demonstrated the way by which curcumin interacts with recombinant TrxR1 and alters the antioxidant enzyme into a reactive oxygen species (ROS) generator in vitro. Herein we reported that curcumin can target the cytosolic/nuclear thioredoxin system to eventually elevate oxidative stress in HeLa cells. Curcumin-modified TrxR1 dose-dependently and quantitatively transfers electrons from NADPH to oxygen with the production of ROS. Also, curcumin can drastically down-regulate Trx1 protein level as well as its enzyme activity in HeLa cells, which in turn remarkably decreases intracellular free thiols, shifting the intracellular redox balance to a more oxidative state, and subsequently induces DNA oxidative damage. Furthermore, curcumin-pretreated HeLa cells are more sensitive to oxidative stress. Knockdown of TrxR1 sensitizes HeLa cells to curcumin cytotoxicity, highlighting the physiological significance of targeting TrxR1 by curcumin. Taken together, our data disclose a previously unrecognized prooxidant mechanism of curcumin in cells, and provide a deep insight in understanding how curcumin works in vivo.

Paris saponin I induces G2/M cell cycle arrest and apoptosis in human gastric carcinoma SGC7901 cells.

The aim of this study was to investigate the effect of Paris saponin I (PS I) on human gastric carcinoma cell growth and apoptosis and to explore the potential mechanisms. The proliferation of SGC7901 cells was monitored by the MTT cell viability assay, while the nuclear morphology of apoptotic cells was assessed by Hoechst 33258 staining. Flow cytometry was performed to analyze the cell cycle progression of propidium iodide (PI)-stained SGC7901 cells and the apoptotic rate of annexin V/PI-stained cells. Western blotting was used to examine the expression of several cell cycle proteins, including cyclin B1 and Cdk1, and the apoptosis-regulated proteins Bcl-2, Bax, cytochrome c, procaspase-9, and procaspase-3. The MTT assay demonstrated that PS I could induce significant dose- and time-dependent inhibition of SGC7901 cell proliferation. Marked morphological changes, including condensation of chromatin, nuclear fragmentation and apoptotic bodies were clearly shown on Hoechst 33258 staining. PSI treatment also resulted in the disruption of the cell cycle at G2/M and the induction of apoptosis. Following PSI treatment, the cell cycle-related proteins cyclin B1 and Cdk1 were down-regulated. Expression of the pro-apoptotic protein Bax was increased, while anti-apoptotic protein Bcl-2 decreased. PSI treatment resulted in elevated cytoplasmic cytochrome c and activation of the apoptotic proteases caspase-9 and caspase-3. These data indicate that PS acts as an inhibitor of proli I feration in SGC7901 cells by inducing cell cycle arrest and mitochondria-dependent apoptosis. PSI is a potential therapeutic agent against human gastric carcinoma.

Protective effect of Acanthopanax gracilistylus-extracted Acankoreanogenin A on mice with fulminant hepatitis.

The release of pro-inflammatory cytokines in both acute (IL-1ß and TNF-α) and chronic [high mobility group box 1 protein (HMGB1)] phases, is thought to play important roles in the development of fulminant hepatitis (FH). Triterpenoid Acankoreanogenin A (AA) which is extracted from the leaves of the Acanthopanax gracilistylus W.W. Smith (AGS) has shown its inhibiting effect on TNF-α, IL-1ß and HMGB1 release in vitro in our preliminary experiments. In present study, we investigated the effect of AA on mice with fulminant hepatitis in vivo. Fulminant hepatitis mice model was established by intraperitoneally injecting galactosamine (GalN) and lipopolysaccharide (LPS). The levels of serum of TNF-α, IL-1ß, ALT, AST and HMGB1 from AA-treated mice were measured at different time points. Our results demonstrated that pre-treatment of mice with AA markedly reduced the serum levels of TNF-α, IL-1ß, HMGB1, ALT and AST with the improvement in histological features. And the survival rate from AA-treated fulminant hepatitis mice was increased. Furthermore, delayed administration of AA after peak occurrence of the early pro-inflammatory cytokines still endowed significant protection against GalN/LPS-induced lethality. The post-treatment of AA could significantly attenuate the release of HMGB1, but not the TNF-α and IL-1ß. These results indicate that AA inhibits the systemic release of pro-inflammatory cytokine HMGB1, and dose-dependently rescue the mice from lethal GalN/LPS-induced fulminant hepatitis, which suggests this component as a candidate therapy for fulminant hepatitis.