The aryl hydrocarbon receptor (AhR) plays an important role in several biological processes such as reproduction, immunity and homoeostasis. However, little is known on the chemical-structural and physicochemical features that influence the activity of AhR antagonistic modulators. In the present report, in vitro AhR antagonistic activity evaluations, based on a chemical-activated luciferase gene expression (AhR-CALUX) bioassay, and an extensive literature review were performed with the aim of constructing a structurally diverse database of contaminants and potentially toxic chemicals. Subsequently, QSAR models based on Linear Discriminant Analysis and Logistic Regression, as well as two toxicophoric hypotheses were proposed to model the AhR antagonistic activity of the built dataset. The QSAR models were rigorously validated yielding satisfactory performance for all classification parameters. Likewise, the toxicophoric hypotheses were validated using a diverse set of 350 decoys, demonstrating adequate robustness and predictive power. Chemical interpretations of both the QSAR and toxicophoric models suggested that hydrophobic constraints, the presence of aromatic rings and electron-acceptor moieties are critical for the AhR antagonism. Therefore, it is hoped that the deductions obtained in the present study will contribute to elucidate further on the structural and physicochemical factors influencing the AhR antagonistic activity of chemical compounds.

Shikonin has been studied as anti-inflammatory [1] and anticancer agent [2]. We previously described the cytotoxic dose-dependent effect on Caco-2 cells of shikonin through the induction of apoptosis by an increase in caspase-3 and the inhibition of the regulating protein Bcl2 [3]. It is known that chronic intestinal inflammation is one of the factors that can trigger a cancerous process. Now, we present the results obtained in a similar experimental method of colorectal cancer (CRC) associated to ulcerative colitis (UC) in C57BL/6 mice. We also evaluated the effect of shikonin on the modulation of IL-17 response.

Numerous studies on intestinal inflammation have established a critical role for the recently discovered Th17 cells, since an amount of this subtype of infiltrating leukocytes and their related cytokines are found in inflamed mucosa of colitic mice and in ulcerative colitis patients, as well. Once we demonstrated that oleuropein acts as an anti-inflammatory agent in such pathological condition, the present study attempts to determine if oleuropein exerts any effect on Th17 cells in a DSS-induced colitis model. Acute colitis was induced to C57BL/6 mice through oral administration of 3% DSS (w/v) in water for 7 days. Animals were randomly assigned to four groups: blank, control, oleuropein (100 mg/kg) and dexamethasone (2.5 mg/kg). After mice were sacrificed at day 8 by cervical dislocation, a piece of 0.5 cm of the distal part of the colon was cut and submitted to cytokine determination by ELISA. Mononuclear cells of lamina propria were isolated and stimulated with ionomycin (500 ng/mL) and phorbol myristate acetate (5 ng/mL). After 4h, cells were collected, incubated with antibodies against CD4, CD3, IL-17A, IFN-γ, and Rorγt, and analysed by FACS.

Shikonin is one of the active principles in the root of Lithospermum erythrorhizon Sieb. & Zucc. (Boraginaceae), widely used in traditional Chinese medicine for its anti-inflammatory and wound-healing properties. Recent research highlights shikonin's anticancer properties as well as its preventive ability in acute ulcerative colitis. To evaluate the potential beneficial effects of shikonin on colorectal cancer, a frequent outcome in ulcerative colitis patients, we studied the antiproliferative effect of this naphthoquinone in human colorectal adenocarcinoma cells (Caco-2). Cytotoxicity of shikonin was evaluated using the colorimetric assay described by Mosmann. Flow cytometry was used to study shikonin's proapoptotic activity and to evaluate its effect on cell cycle. Moreover, the study was complemented with the analysis by Western blot of the expression of proteins that play a key role in the apoptotic process.

The beneficial effects of the secoiridoid oleuropein, mainly found in leaves of olive tree (Olea europaea), are known for a long time. Our studies are focussed on the ability of this polyphenol to protect from inflammation, especially in large intestine. We tested its effect successfully in two intestinal acute and chronic inflammatory models, using dextran sulphate sodium (DSS) [1, 2]. A chronic intestinal inflammation, together with other factors, can trigger a cancerous process, so considering our positive results and its antitumoral properties, could oleuropein prevent the occurrence of colorectal cancer (CRC) using the azoxymethane (AOM)/DSS model in C57BL/6 mice? Mice received a single i.p. injection of AOM at day 0 and three cycles of DSS starting day 7. Each cycle consisted in 7 days of DSS 1.5% followed by 14 days of drinking water. Mice were randomized in 8 treatment groups: Control (drinking water), DSS (DSS cycles), AOM (AOM injection), AOM/DSS (AOM injection and DSS cycles), O50 (50 mg/kg oleuropein in water), O100 (100 mg/kg oleuropein in water), and ASA (75 mg/kg 5-aminosalycilic acid in water). At day 63 mice were sacrificed, colons removed and submitted to macroscopical examinations. Different pathways involved in tumor development were determined by western blot. Statistical significance was determined by analysis of variance (ANOVA) and Dunnet't test. Oleuropein suppressed the growth and multiplicity of colonic tumors (84%, p < 0.01), decreased COX-2 (70%, p < 0.01) expression and reduced nuclear p65 NF-κB subunit (49%, p < 0.01). Moreover, oleuropein regulated apoptotic proteins such as Bax (30%, p < 0.05), reduced the translocation of β-catenin (49%, p < 0.01) to the nucleus and the activation of pathways implicated on growth tumor: AKT/PI3K (40%, p < 0.05) and STAT-3 phosphorylation (35%, p < 0.05). The reference drug 5-ASA was effective in preventing CRC. In conclusion, oleuropein is a promising protective agent against CRC.

Shikonin is the major constituent of the root of Lithospermum erythrorhizon, which has been used in traditional Chinese medicine to treat external wounds, burns, or dermatitis for centuries. Nowadays, this root is commonly used as an herbal medicine against cancer. Studies carried out over the past 30 years have demonstrated that many of the effects historically associated with the use of this root have a scientific basis, with shikonin and its derivatives being responsible for its pharmacological properties. These include both anti-inflammatory and anticancer effects. While previous summaries have focused on the pharmacokinetics and toxicity of shikonin, the aim of this review is to report on the most current findings with regard to shikonin's antitumor activity by summarizing and comparing the various studies published in the last ten years and discussing the pharmacological aspects that make shikonin a promising anticancer agent.

The intestinal barrier is a complex system with a dynamic structure that is designed for the maintenance of homeostasis in healthy individuals. Ulcerative colitis, one of the main manifestations of inflammatory bowel disease, is characterized by an inadequate and delayed wound healing. Shikonin, the active principle in the root of Lithospermum erythrorhizon, has demonstrated its ability to attenuate dextran sulfate sodium-induced ulcerative colitis in mice. Moreover, the root of L. erythrorhizon has been used in traditional Chinese medicine for treatment of burns, anal ulcers, hemorrhoids and skin wounds. However, the effect of shikonin on intestinal wound healing is unknown. Using an in vitro model for wound healing, we observed that shikonin enhances cell migration of intestinal epithelial cells through a mechanism that involves TGF-β1 induction. The combination of shikonin's anti-inflammatory activity together with its wound-healing properties makes it a great potential therapeutic agent for the treatment of injury associated with intestinal inflammation.

This paper compiles the beneficial effects of cocoa polyphenols on human health, especially with regard to cardiovascular and inflammatory diseases, metabolic disorders, and cancer prevention. Their antioxidant properties may be responsible for many of their pharmacological effects, including the inhibition of lipid peroxidation and the protection of LDL-cholesterol against oxidation, and increase resistance to oxidative stress. The phenolics from cocoa also modify the glycemic response and the lipid profile, decreasing platelet function and inflammation along with diastolic and systolic arterial pressures, which, taken together, may reduce the risk of cardiovascular mortality. Cocoa polyphenols can also modulate intestinal inflammation through the reduction of neutrophil infiltration and expression of different transcription factors, which leads to decreases in the production of proinflammatory enzymes and cytokines. The phenolics from cocoa may thus protect against diseases in which oxidative stress is implicated as a causal or contributing factor, such as cancer. They also have antiproliferative, antimutagenic, and chemoprotective effects, in addition to their anticariogenic effects.

Triterpenes have been reported to induce cell death. One relevant group of this family of compounds is cucurbitacins, which have been studied as inducers of apoptosis in various cancer cell lines. The most significant mechanisms with regard to the apoptotic effects of cucurbitacins are their ability to modify transcriptional activities via nuclear factors or genes and their capability to activate or inhibit pro- or anti-apoptotic proteins. Still, while the majority of studies on these compounds have dealt with their apoptotic effects on cancer cell lines, several research groups have also explored their anti-inflammatory activities. In general, cucurbitacins are considered to be selective inhibitors of the JAK/STAT pathways; however, other mechanisms may be implicated in their apoptotic effects, including the MAPK pathway (known to be important for cancer cell proliferation and survival), PARP cleavage, expression of active caspase-3, decreased pSTAT3 and JAK3 levels, as well as decreases in various downstream STAT3 targets such as Mcl-1, Bcl-2, Bcl-xL, and cyclin D3, all of which are implicated in apoptosis and the cell cycle. Taking all these effects into account, cucurbitacins may prove useful in the treatment of different kinds of cancers, especially when used with other cytostatic agents.

Shikonin (Shk) inhibits the development of colorectal dysplasia and the colitis induced in a mouse model of azoxymethane (AOM)/dextran sulfate sodium (DSS), as demonstrated both by macroscopic and biochemical determinations. The oral administration of shikonin prevents weight loss and colorectum shortening. Histological analysis revealed a decrease both in the severity and extent of inflammation, together with an amelioration of the colonic architecture and the protection from the appearance of dysplasia. This was associated reduction in MPO activity together with the inhibition of COX-2 and iNOS expression. A possible mechanism of action which would be responsible for this protection is the inhibition of NF-κB activation, since we demonstrated the inhibition of the translocation of NF-κB-p65 subunit to the nucleus in the colon homogenate. As a positive control we examined the effect of oral administration of sulfasalazine (Ssz).

The implantation of the European Higher Education Area (EHEA) requires an educational system rooted in a competency-based learning approach in which, under professorial supervision, the students become active agents in order to reach a sufficient level of competence, retain more knowledge, and manage and apply this knowledge more efficiently. It implies modifying not only our teaching practices, but also our methods of evaluation, which, as an essential part of the education process, guarantees the acquisition of an ample range of skills and keeps course material up to date while providing students and educators with feed-back, reflection and analysis of the whole process. This, in turn, facilitates the correction of deficiencies and improvement of methodologies. In Pharmacognosy, which is currently taught in the second year of the Pharmacy program and in which ca. 200 students are enrolled, various evaluation strategies coherent with the established learning objectives were introduced to two groups of students. We first administered a questionnaire to ascertain the range of knowledge the students already had in related subjects. Then, two types of test were given: one type emphasizing the acquisition and understanding of knowledge and the other type focussing on more generic, interdisciplinary competence. The former type included: on-line multiple choice questionnaires, which allow for discernment of information and quick feed-back; open answer