Silibinin improves L-cell mass and function through an estrogen receptor-mediated antioxidative mechanism.

BACKGROUND: Silibinin, a major component of milk thistle extract silymarin, promotes hypoglycemia by activating estrogen receptor (ER) α and ß-mediated pathways in pancreatic ß-cells. Glucagon-like peptide-1 (GLP-1) is the enteroendocrine peptide produced in L-cells, and it controls glucose homeostasis through multiple pathways. The effect of silibinin on L-cell mass and function is still unknown. PURPOSE: The protective effect of silibinin on palmitate (PA)-treated intestinal L-cell line GLUTag cells and the SHRSP•Z-Leprfa/Izm-Dmcr (SP•ZF) diabetic rat model was investigated in current study. METHODS: After pre-incubation with 50 µM silibinin for 4 h, GLUTag cells were treated with 0.125 mM PA. MTT, Annexin V/PI apoptosis, Hoechst 33342 staining, western blot, DCFH-DA, GLP-1 ELISA, qRT-PCR and immunofluorescence analyses were undertaken to determine ER-dependent protection of silibinin against PA-induced cellular damage. The differential protein expression of GLUTag cells under different treatments was examined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). The SP•ZF diabetic rat model was chosen for in vivo study. After 4 weeks of gastric gavage with 100 or 300 mg kg-1 of silibinin, the physiological indexes of the rats were measured. Cells expressing GLP-1, 8­hydroxy-2'-deoxyguanosine (8-OHdG), ERα, and/or ERß in duodenum tissues were detected by immunofluorescence. RESULTS: The current study showed that the GLUTag cells preincubated with silibinin activated the transcription factor nuclear erythroid-2 like factor-2 (Nrf2)-antioxidant pathway, reduced reactive oxygen species (ROS) generation, and improved cell survival and GLP-1 content, while the antioxidative effect of silibinin was blocked by the selective ERα antagonist MPP or ERß antagonist PHTPP in GLUTag cells. Our proteomics data further revealed that ERα or ß inactivation reduced glutathione peroxide and proteins associated with endocytosis and reproduction, thus at least partially reversing the protective effect of silibinin. SP•ZF rats received silibinin treatment showed increased serum GLP-1 content and improved glucose homeostasis. Furthermore, silibinin upregulated ERα and ß levels and reduced the level of 8-OHdG in GLP-1-positive cells. CONCLUSIONS: Our study showed that silibinin improved L-cell mass and function through an ER-mediated antioxidant pathway, and the proteomics analysis revealed for the first time the differential regulation of proteins by PA and silibinin in GLUTag cells.

Dammarane-type leads panaxadiol and protopanaxadiol for drug discovery: Biological activity and structural modification.

Based on the definite therapeutic benefits, such as neuroprotective, cardioprotective, anticancer, anti-diabetic and so on, the Panax genus which contains many valuable plants, including ginseng (Panax ginseng C.A. Meyer), notoginseng (Panax notoginseng) and American ginseng (Panax quinquefolius L.), attracts research focus. Actually, the biological and pharmacological effects of the Panax genus are mainly attributed to the abundant ginsenosides. However, the low membrane permeability and the gastrointestinal tract influence seriously limit the absorption and bioavailability of ginsenosides. The acid or base hydrolysates of ginsenosides, 20 (R,S)-panaxadiol and 20 (R,S)-protopanaxadiol showed improved bioavailability and diverse pharmacological activities. Moreover, relative stable skeletons and active hydroxyl group at C-3 position and other reactive sites are suitable for structural modification to improve biological activities. In this review, the pharmacological activities of panaxadiol, protopanaxadiol and their structurally modified derivatives are comprehensively summarized.

A Novel, Multi-Target Natural Drug Candidate, Matrine, Improves Cognitive Deficits in Alzheimer's Disease Transgenic Mice by Inhibiting Aß Aggregation and Blocking the RAGE/Aß Axis.

The treatment of AD is a topic that has puzzled researchers for many years. Current mainstream theories still consider Aß to be the most important target for the cure of AD. In this study, we attempted to explore multiple targets for AD treatments with the aim of identifying a qualified compound that could both inhibit the aggregation of Aß and block the RAGE/Aß axis. We believed that a compound that targets both Aß and RAGE may be a feasible strategy for AD treatment. A novel and small natural compound, Matrine (Mat), was identified by high-throughput screening of the main components of traditional Chinese herbs used to treat dementia. Various experimental techniques were used to evaluate the effect of Mat on these two targets both in vitro and in AD mouse model. Mat could inhibit Aß42-induced cytotoxicity and suppress the Aß/RAGE signaling pathway in vitro. Additionally, the results of in vivo evaluations of the effects of Mat on the two targets were consistent with the results of our in vitro studies. Furthermore, Mat reduced proinflammatory cytokines and Aß deposition and attenuated the memory deficits of AD transgenic mice. We believe that this novel, multi-target strategy to inhibit both Aß and RAGE, is worthy of further exploration. Therefore, our future studies will focus on identifying even more effective multi-target compounds for the treatment of AD based on the molecular structure of Mat.

Cytotoxic Activity of Compounds from Styrax obassia.

Cancer is a major public health burden in both developed and developing countries. Plant-derived compounds have played an important role in the development of useful anti-cancer agents. The current study was designed to evaluate the cytotoxic activity of chemical compounds from the stem bark of Styrax obassia. Seven known compounds (1-7) were isolated and identified. Compound 2 exhibited cytotoxic activity against the breast cancer cell line MCF-7 with an IC550 of 27.9 µM, followed by the human cervical cancer cell line Hela with an IC50 of 23.3 µM, and the human promyelocytic leukemia cell line HL-60 with an IC50 of 47.8 RM. Compound 7 exhibited cytotoxicity against Hela cells with an ICso of 16.8 pM, followed by MCF-7 cells with an IC50 of 53.5 µM. This is the first study to investigate the significant anti-tumor properties of isolated compounds from the stem bark of S. obassia.

Identification of the protopanaxatriol synthase gene CYP6H for ginsenoside biosynthesis in Panax quinquefolius.

Panax quinquefolius is one of perennial herbs and well known for its outstanding pharmacological activity. Ginsenosides are thought to be the main active ingredients in P. quinquefolius and exist in many kinds of plant genus Panax (ginseng). Protopanaxatriol synthase, which is considered cytochrome P450 (CYP450) in ginsenoside biosynthesis pathway can convert protopanaxadiol into protopanaxatriol. However, the protopanaxatriol synthase gene in P. quinquefolius has not been identified. Here, we cloned and identified a protopanaxatriol synthase gene from P. quinquefolius (CYP6H, GenBank accession no. KC190491) at the first time, reverse transcription-PCR (RT-PCR) analysis showed no obvious transcription change of CYP6H in methyl jasmonate (MeJA)-induced hairy roots. Ectopic expression of CYP6H in Saccharomyces cerevisiae resulted in the production of protopanaxatriol with added exogenous protopanaxadiol and confirmed by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC/APCIMS). Moreover, high-performance liquid chromatography (HPLC) analysis shows that RNA interferences of CYP6H in transgenic hairy roots could increase the accumulation of protopanaxadiol-type ginsenosides and decrease the accumulation of protopanaxatriol-type ginsenosides, whereas the effect of overexpression CYP6H in transgenic hairy roots was contrary. Our study indicated that CYP6H is a gene encoding protopanaxadiol 6-hydroxylase which could convert protopanaxadiol into protopanaxatriol in P. quinquefolius ginsenoside biosynthesis, we also have confirmed the function of CYP6H on effect accumulation of ginsenosides.

The isolation and characterization of dammarenediol synthase gene from Panax quinquefolius and its heterologous co-expression with cytochrome P450 gene PqD12H in yeast.

Panax quinquefolius is one of perennial herbs and well known for its outstanding pharmacological activity. Ginsenosides are thought to be the main active ingredients in Panax quinquefolius and exist in many kinds of plant genus Panax (ginseng). Dammarenediol synthase, which is considered as a key enzyme in ginsenoside biosynthesis pathway can convert 2, 3-oxidosqualene into dammarenediol-II. However, the dammarenediol synthase gene in Panax quinquefolius has not been identified. Here, we cloned and identified a dammarenediol synthase gene from Panax quinquefolius (PqDS, GenBank accession No. KC316048) at the first time, and reverse transcription-PCR (RT-PCR) analysis also showed an obvious transcription increase of PqDS in the methyl jasmonate (MeJA)-induced hairy roots. Ectopic expression of PqDS in yeast resulted in the production of dammarenediol-II was confirmed by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC/APCIMS). Moreover, overexpression of PqDS in transgenic hairy roots could increase the transcription of gene PqDS and another P450 gene PqD12H (encoding protopanaxadiol synthase in Panax quinquefolius), the accumulation of ginsenosides also increased at the same time. In addition, both PqDS and PqD12H gene co-expressed in recombinant yeast result in the production of protopanaxadiol was detected by LC/APCIMS; this result also provides a new strategy for the abundant production of protopanaxadiol in vitro.

Meta-analysis of the clinical value of danshen injection and huangqi injection in liver cirrhosis.

Objective. To evaluate the clinical value of Danshen injection and Huangqi injection for the treatment of liver cirrhosis. Methods. The Chinese Biomedical Literature Database (CBM), Chinese Scientific Journals Full-Text Database (VIP), Wanfang Database, China National Knowledge Infrastructure (CNKI), PubMed, and EMBASE database were searched to collect the literatures about the randomized controlled trials involving the treatment of liver cirrhosis with Danshen injection combined with Huangqi injection, and the data analyses were performed using RevMan 4.2 software. Results. A total of 11 studies involving 1086 patients (trials group: 554 cases, control group: 532 cases) were included in this study. Compared with those in control group, the meta-analysis showed-that the total effectiveness rate and the level of serum albumin increased, while serum total bilirubin, alanine transmninase, type III procollagen, hyaluronic acid, laminin, and type-IV collagen decreased in trials group. The Jadad score ranged from 1 to 2 and the funnel plot analysis suggests that publication bias may occur. Conclusions. Danshen injection combined with Huangqi injection may promote the curative efficacy of liver cirrhosis, which is a promising novel treatment approach. The exact outcome needs to perform rigorously designed, multicenter, and large randomized controlled trials.