Suitability of the MTT-based cytotoxicity assay to detect okadaic acid contamination of mussels

Discovery of N-(phenylsulfonyl)thiazole-2-carboxamides as potent α-glucosidase inhibitors

In a search for novel nonsugar α-glucosidase inhibitors for diabetes treatment, a series of N-(phenylsulfonyl)thiazole-2-carboxamide derivatives were designed and synthesized, the α-glucosidase inhibitory activities were then evaluated. Several compounds with promising α-glucosidase inhibitory effects were identified. Among these, compound W24 which shows low cytotoxicity and good α-glucosidase inhibitory activity with an IC50 value of 53.0 ± 7.7 μM, is more competitive compared with the commercially available drug acarbose (IC50  = 228.3 ± 9.2 μM). W24 was identified as a promising candidate in the development of α-glucosidase inhibitors. Molecular docking studies and molecular dynamics simulation were also performed to reveal the binding pattern of the active compound to α-glucosidase, and the binding free energy of the best compound W24 was 36.3403 ± 3.91 kcal/mol.

A Review of In Situ Methods-Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) for the Collection and Concentration of Marine Biotoxins and Pharmaceuticals in Environmental Waters

Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) are in situ methods that have been applied to pre-concentrate a range of marine toxins, pesticides and pharmaceutical compounds that occur at low levels in marine and environmental waters. Recent research has identified the widespread distribution of biotoxins and pharmaceuticals in environmental waters (marine, brackish and freshwater) highlighting the need for the development of effective techniques to generate accurate quantitative water system profiles. In this manuscript, we reviewed in situ methods known as Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) for the collection and concentration of marine biotoxins, freshwater cyanotoxins and pharmaceuticals in environmental waters since the 1980s to present. Twelve different adsorption substrates in SPATT and 18 different sorbents in POCIS were reviewed for their ability to absorb a range of lipophilic and hydrophilic marine biotoxins, pharmaceuticals, pesticides, antibiotics and microcystins in marine water, freshwater and wastewater. This review suggests the gaps in reported studies, outlines future research possibilities and guides researchers who wish to work on water contaminates using Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) technologies.

Anti-proliferative and anti-inflammatory prenylated isoflavones and coumaronochromones from the fruits of Ficus altissima

Ficus altissima, an evergreen arbor belonging to the Moraceae family, is mainly cultivated in the tropics and subtropics of South and Southeast Asia with the characteristic of exuberant vitality and luxuriant foliage. In this article, four new prenylated isoflavones (1-4), along with ten previously described isoflavones (5-14) and two known prenylated coumaronochromones (15 and 16) were firstly obtained from the fruits of F. altissima. Their structures were identified by various spectroscopic techniques including specific optical rotation, HR-ESI-MS and NMR. The isolated products were evaluated for their anti-proliferative activities against three human tumor cell lines (HepG2, MCF-7 and MDA-MB-231) through MTT assay. Compounds 2, 3 and 16 exhibited obvious anti-proliferative activities against MDA-MB-231 cell line and compounds 3, 13 and 16 showed effective cytotoxic effects on HepG2 cell line in a concentration-dependent manner, as verified by the colony formation assay, cell and nucleus morphological assessment and apoptosis assay. Meanwhile, compounds 5 and 12 exhibited significant inhibition activities on NO production in LPS-stimulated RAW 264.7 cell line compared with positive control indometacin. The phytochemical investigation of the fruits of F. altissima in this study could provide the evidence for the discovery of lead compounds.

A pH and UCST thermo-responsive tri-block copolymer (PAA-b-PDMA-b-P(AM-co-AN)) with micellization and gelatinization in aqueous media for drug release

A brand new pH and thermo-responsive amphiphilic ABC triblock copolymer of poly(acrylic acid)-block-poly(N,N-dimethyl acrylamide)-block-poly(acrylamide-co-acrylonitrile) (PAA-b-PDMA-b-P(AM-co-AN)) was applied as drug carrier systems.

Marine Toxins Detection by Biosensors Based on Aptamers

Marine toxins cause great harm to human health through seafood, therefore, it is urgent to exploit new marine toxins detection methods with the merits of high sensitivity and specificity, low detection limit, convenience, and high efficiency. Aptasensors have emerged to replace classical detection methods for marine toxins detection. The rapid development of molecular biological approaches, sequencing technology, material science, electronics and chemical science boost the preparation and application of aptasensors. Taken together, the aptamer-based biosensors would be the best candidate for detection of the marine toxins with the merits of high sensitivity and specificity, convenience, time-saving, relatively low cost, extremely low detection limit, and high throughput, which have reduced the detection limit of marine toxins from nM to fM. This article reviews the detection of marine toxins by aptamer-based biosensors, as well as the selection approach for the systematic evolution of ligands by exponential enrichment (SELEX), the aptamer sequences. Moreover, the newest aptasensors and the future prospective are also discussed, which would provide thereotical basis for the future development of marine toxins detection by aptasensors.

Bioassays as one of the Green Chemistry tools for assessing environmental quality: A review

For centuries, mankind has contributed to irreversible environmental changes, but due to the modern science of recent decades, scientists are able to assess the scale of this impact. The introduction of laws and standards to ensure environmental cleanliness requires comprehensive environmental monitoring, which should also meet the requirements of Green Chemistry. The broad spectrum of Green Chemistry principle applications should also include all of the techniques and methods of pollutant analysis and environmental monitoring. The classical methods of chemical analyses do not always match the twelve principles of Green Chemistry, and they are often expensive and employ toxic and environmentally unfriendly solvents in large quantities. These solvents can generate hazardous and toxic waste while consuming large volumes of resources. Therefore, there is a need to develop reliable techniques that would not only meet the requirements of Green Analytical Chemistry, but they could also complement and sometimes provide an alternative to conventional classical analytical methods. These alternatives may be found in bioassays. Commercially available certified bioassays often come in the form of ready-to-use toxkits, and they are easy to use and relatively inexpensive in comparison with certain conventional analytical methods. The aim of this study is to provide evidence that bioassays can be a complementary alternative to classical methods of analysis and can fulfil Green Analytical Chemistry criteria. The test organisms discussed in this work include single-celled organisms, such as cell lines, fungi (yeast), and bacteria, and multicellular organisms, such as invertebrate and vertebrate animals and plants.

Graphene oxide-assisted non-immobilized SELEX of okdaic acid aptamer and the analytical application of aptasensor

Okadaic acid (OA) is a low-molecular-weight marine toxin from shellfish that causes abdominal pain, vomiting and diarrhea, i.e., diarrheic shellfish poisoning. In this study, a ssDNA aptamer that specifically binds to OA with high affinity was obtained via Systematic Evolution of Ligands by Exponential Enrichment (SELEX) assisted by graphene oxide (GO). This aptamer was then applied to fabricate a novel direct competitive enzyme-linked aptamer assay (ELAA). At the optimized conditions, this ELAA method showed a low detection limit (LOD of 0.01 ng/mL), wide linear range (from 0.025 to 10 ng/mL), good recovery rate (92.86–103.34% in OA-spiked clam samples) and repeatability (RSD of 2.28–4.53%). The proposed method can be used to detect OA in seafood products with high sensitivity and can potentially be adapted for the determination of other small molecular analytes.

Antioxidant, antimicrobial and antiproliferative activities of Anthemis palestina essential oil

Background

Anthemis palestina (Asteraceae) extends across the Mediterranean region, southwest Asia and eastern Africa. Although traditionally used for several applications, in vitro investigation of biological functions associated with Anthemis palestina essential oil had never been reported.

Methods

The air-dried flowers of Anthemis palestina were subjected to hydrodistillation to yield the oil. The antioxidant activity of the hydrodistilled oil was characterized using various in vitro model systems such as DPPH, ferric-reducing antioxidant power and hydroxyl radical scavenging activity. Antibacterial activity was tested against six bacterial species, representing both Gram positive and Gram negative bacteria. Antifungal activity was evaluated using three Candida species. The minimum inhibitory concentration (MIC) for each examined microorganism was determined using the microdilution method. The oil’s antiproliferative effects against eight human cancer cell lines were also studied and the lethal doses that resulted in 50% reduction of cell viability (LD₅₀) were determined.

Results

The results indicate that the essential oil of Anthemis palestina exhibited substantial antioxidant activities as demonstrated with DPPH, ferric reducing antioxidant power, and hydroxyl radical scavenging activity. In addition, a broad-spectrum antibacterial activity of the oil was revealed with better susceptibility of Gram positive bacteria towards the oil. The MIC values ranged between 6–75 μg/ml. Besides, the oil demonstrated a moderate inhibitory effect on the three Candida species examined; with MIC values ranging between 48–95 μg/ml. Potent cytotoxic activities, especially against HeLa cell line; with LD₅₀ of 32 μg/ml, BJAB cell line; with LD₅₀ of 57 μg/ml, and Caco-2 cell line; with LD₅₀ of 61 μg/ml, were observed.

Conclusion

The results obtained indicate high potential of Anthemis palestina essential oil as bioactive oil, for nutraceutical and medical applications, possessing antioxidant, antimicrobial and antiproliferative activities.

Antioxidant and Anti-inflammatory Activities of Butanol Extract of Melaleuca leucadendron L

Melaleuca leucadendron L. has been used as a tranquilizing, sedating, evil-dispelling and pain-relieving agent. We examined the effects of M. leucadendron L. extracts on oxidative stress and inflammation. M. leucadendron L. was extracted with methanol (MeOH) and then fractionated with chloroform (CHCl3) and butanol (BuOH). Antioxidant activity of the MeOH extract and BuOH fraction were higher than that of both α-tocopherol and butyrated hydroxytoluene (BHT). Total phenol content in the extracts of M. leucadendron L., especially the BuOH fraction, well correlated with the antioxidant activity. The anti-inflammatory activity of BuOH extracts were investigated by lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production, and cyclooxygenase-2 (COX-2) expression in RAW 264.7 macrophages. The BuOH fraction significantly inhibited LPS-induced NO and PGE2 production. Furthermore, BuOH extract of M. leucadendron L. inhibited the expression of COX-2 and iNOS protein without an appreciable cytotoxic effect on RAW264.7 cells. The extract of M. leucadendron L. also suppressed the phosphorylation of inhibitor κBα (IκBα) and its degradation associated with nuclear factor-κB (NF-κB) activation. Furthermore, BuOH fraction inhibited LPS-induced NF-κB transcriptional activity in a dose-dependent manner. These results suggested that M. leucadendron L. could be useful as a natural anti-oxidant and anti-inflammatory resource.

Dinophysis toxins: causative organisms, distribution and fate in shellfish

Several Dinophysis species produce diarrhoetic toxins (okadaic acid and dinophysistoxins) and pectenotoxins, and cause gastointestinal illness, Diarrhetic Shellfish Poisoning (DSP), even at low cell densities (<103 cells·L⁻¹). They are the main threat, in terms of days of harvesting bans, to aquaculture in Northern Japan, Chile, and Europe. Toxicity and toxin profiles are very variable, more between strains than species. The distribution of DSP events mirrors that of shellfish production areas that have implemented toxin regulations, otherwise misinterpreted as bacterial or viral contamination. Field observations and laboratory experiments have shown that most of the toxins produced by Dinophysis are released into the medium, raising questions about the ecological role of extracelular toxins and their potential uptake by shellfish. Shellfish contamination results from a complex balance between food selection, adsorption, species-specific enzymatic transformations, and allometric processes. Highest risk areas are those combining Dinophysis strains with high cell content of okadaates, aquaculture with predominance of mytilids (good accumulators of toxins), and consumers who frequently include mussels in their diet. Regions including pectenotoxins in their regulated phycotoxins will suffer from much longer harvesting bans and from disloyal competition with production areas where these toxins have been deregulated.

Cytotoxicity, fractionation and dereplication of extracts of the dinoflagellate Vulcanodinium rugosum, a producer of pinnatoxin G

Pinnatoxin G (PnTX-G) is a marine toxin belonging to the class of cyclic imines and produced by the dinoflagellate Vulcanodinium rugosum. In spite of its strong toxicity to mice, leading to the classification of pinnatoxins into the class of “fast-acting toxins”, its hazard for human health has never been demonstrated. In this study, crude extracts of V. rugosum exhibited significant cytotoxicity against Neuro2A and KB cells. IC₅₀ values of 0.38 µg mL⁻¹ and 0.19 µg mL⁻¹ were estimated on Neuro2A cells after only 24 h of incubation and on KB cells after 72 h of incubation, respectively. In the case of Caco-2 cells 48 h after exposure, the crude extract of V. rugosum induced cell cycle arrest accompanied by a dramatic increase in double strand DNA breaks, although only 40% cytotoxicity was observed at the highest concentration tested (5 µg mL⁻¹). However, PnTX-G was not a potent cytotoxic compound as no reduction of the cell viability was observed on the different cell lines. Moreover, no effects on the cell cycle or DNA damage were observed following treatment of undifferentiated Caco-2 cells with PnTX-G. The crude extract of V. rugosum was thus partially purified using liquid-liquid partitioning and SPE clean-up. In vitro assays revealed strong activity of some fractions containing no PnTX-G. The crude extract and the most potent fraction were evaluated using full scan and tandem high resolution mass spectrometry. The dereplication revealed the presence of a major compound that could be putatively annotated as nakijiquinone A, N-carboxy-methyl-smenospongine or stachybotrin A, using the MarinLit™ database. Further investigations will be necessary to confirm the identity of the compounds responsible for the cytotoxicity and genotoxicity of the extracts of V. rugosum.

Okadaic acid meet and greet: an insight into detection methods, response strategies and genotoxic effects in marine invertebrates

Harmful Algal Blooms (HABs) constitute one of the most important sources of contamination in the oceans, producing high concentrations of potentially harmful biotoxins that are accumulated across the food chains. One such biotoxin, Okadaic Acid (OA), is produced by marine dinoflagellates and subsequently accumulated within the tissues of filtering marine organisms feeding on HABs, rapidly spreading to their predators in the food chain and eventually reaching human consumers causing Diarrhetic Shellfish Poisoning (DSP) syndrome. While numerous studies have thoroughly evaluated the effects of OA in mammals, the attention drawn to marine organisms in this regard has been scarce, even though they constitute primary targets for this biotoxin. With this in mind, the present work aimed to provide a timely and comprehensive insight into the current literature on the effect of OA in marine invertebrates, along with the strategies developed by these organisms to respond to its toxic effect together with the most important methods and techniques used for OA detection and evaluation.

In vitro acylation of okadaic acid in the presence of various bivalves' extracts

The dinoflagellate Dinophysis spp. is responsible for diarrhetic shellfish poisoning (DSP). In the bivalves exposed to the toxic bloom of the dinoflagellate, dinophysistoxin 3 (DTX3), the 7-OH acylated form of either okadaic acid (OA) or DTX1, is produced. We demonstrated in vitro acylation of OA with palmitoyl CoA in the presence of protein extract from the digestive gland, but not other tissues of the bivalve Mizuhopecten yessoensis. The yield of 7-O-palmitoyl OA reached its maximum within 2 h, was the highest at 37 °C followed by 28 °C, 16 °C and 4 °C and was the highest at pH 8 in comparison with the yields at pH 6 and pH 4. The transformation also proceeded when the protein extract was prepared from the bivalves Corbicula japonica and Crassostrea gigas. The OA binding protein OABP2 identified in the sponge Halichondria okadai was not detected in the bivalve M. yessoensis, the bivalve Mytilus galloprovincialis and the ascidian Halocynthia roretzi, though they are known to accumulate diarrhetic shellfish poisoning toxins. Since DTX3 does not bind to protein phosphatases 1 and 2A, the physiological target for OA and DTXs in mammalian cells, the acylation of DSP toxins would be related to a detoxification mechanism for the bivalve species.

Evaluation of cytotoxic compounds in different organs of the sea bream Sarpa salpa as related to phytoplankton consumption: an in vitro study in human liver cell lines HepG2 and WRL68

The present study was aimed to assess the cytotoxic effects of not-yet identified compounds present in organ extracts of Sarpa salpa, collected in autumn, the period with a peak in health problems. In addition, we studied the cytotoxicity of extracts of epiphytes found in the stomach content of S. salpa collected in summer and of epiphytes collected from the sea in the Sfax area at the end of spring. We tested these fractions in two human hepatic cell lines: HepG2 and WRL68. We observed a significant loss of viable cells when HepG2 cells were exposed for 72 h to acetone extracts of livers of S. salpa at a concentration of 2.5 mg/ml protein. Proteins extracted from brain or muscle did not significantly induce cell death at the studied concentrations (≤10 mg/ml). There was a significant loss of viable cells when treated with liver extract of S. salpa dissolved in DMSO. Extracts of epiphytes collected in late spring showed a cytotoxic effect in a concentration-dependent manner. Moreover, we observed a significantly decreased cell viability of HepG2 at a dilution (1/40) of epiphyte extracts from stomach contents of two fish we had collected. The cytotoxic effect of the observed epiphyte extracts confirms the transfer of toxins originating from toxic dinoflagellates which live in epiphyte on the Posidonia oceanica leaves to fish organs by grazing. Hence, the liver of this fish can cause a threat to human health and consumption should for this reason be dissuaded.

Evaluation of phototoxic potential of aerial components of the fig tree against human melanoma

OBJECTIVES

To date, Ficus carica L. cultivar Dottato (F. carica) has not been studied from a phototoxic point of view. In the present work, aerial components of F. carica from Italy, were examined to assess their antioxidant and phototoxic activity on human melanoma cells. A relationship between antioxidant, phototoxic activities and chemical composition has also been investigated.

MATERIALS AND METHODS

Coumarin and fatty acid content in F. carica leaves, bark and woody parts were examined and compared by capillary GC and GC/MS. Polyphenolic content was also determined. Linoleic acid peroxidation and DPPH test were used to assess antioxidant activities, and MTT assay was used to evaluate anti-proliferative activity, on C32 human melanoma cells, after irradiation with a UVA dose of 1.08 J/cm(2).

RESULTS

Leaves demonstrated the best antioxidant and anti-proliferative activity in comparison to bark and wood. In particular, leaves were shown to possess the highest anti-radical activity and inhibition of peroxidation, with IC(50) values of 64 and 1.48 μg/ml respectively. The leaves had highest anti-proliferative activity with IC(50) value of 3.92 μg/ml. The phytochemical investigation revealed different composition between the coumarins, psoralen and bergapten, fatty acids, polyphenols and flavonoid content among plant parts.

CONCLUSIONS

Data obtained indicate that this type of fig tree may constitute an excellent source of bioactive compounds, such as phenolics, coumarins and fatty acids. This study offers a new perspective in developing others formulations potentially useful in photodynamic therapy for treatment of non-melanoma skin cancers.

Anthemis wiedemanniana essential oil prevents LPS-induced production of NO in RAW 264.7 macrophages and exerts antiproliferative and antibacterial activities in vitro

Anthemis wiedemanniana is known in folk medicine for the treatment of microbial infections, cancer and also urinary and pulmonary problems. In this study, the chemical composition of the essential oil from A. wiedemanniana was evaluated and its antibacterial activity was tested against 10 bacterial strains. The oil was also tested for its potentiality to inhibit nitric oxide production in RAW 264.7 macrophages and for its cytotoxicity against four human cancer cell lines. A. wiedemanniana oil, rich of oxygenated monoterpenes (25.4%), showed a good antibacterial activity against Gram-positive bacteria and a good activity against the two Gram-negative bacteria, Escherichia coli and Proteus vulgaris. Besides that, it exhibited a high inhibitory effect on the LPS-induced nitrite production and a strong cytotoxic activity, especially against amelanotic melanoma (C32) and large lung cell carcinoma (COR-L23) cell lines.

Chemical composition and protective effect of oregano (Origanum heracleoticum L.) ethanolic extract on oxidative damage and on inhibition of NO in LPS-stimulated RAW 264.7 macrophages

The present study shows the chemical profile and the in vitro properties (antioxidant and inhibition of nitric oxide production) of the Origanum heracleoticum L. (Lamiaceae). The ethanolic extract of the aerial parts is characterized by terpenes and fatty acids. The extract, with high total phenol and flavonoid content, showed a significant radical-scavenging activity (IC(50) value of 12.8 μg/mL) using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test and an interesting antioxidant activity with the β-carotene bleaching test (IC(50) values of 12.9 and 14.1 μg/mL at 30 and 60 min of incubation, respectively). The test for the inhibition of NO production, performed using the murine monocytic macrophage RAW 264.7 cell line, showed that the extract had significant activity with an IC(50) value of 108.5 μg/mL. The cytotoxic effect of O. heracleoticum extract in presence of lipopolysaccharide (LPS) (1 μg/mL) was evaluated but found to be negligible.

The Influence of Collection Zone on Glucosinolates, Polyphenols and Flavonoids Contents and Biological Profiles of Capparis sicula ssp. sicula

This study aimed to evaluate the influence of collection zone on total phenol, flavonoid and glucosinolate contents and antioxidant and anti-inflammatory activities of caper ( Capparis sicula ssp. sicula). This species has been characterized through the detection, isolation and quantitative evaluation of chemical markers (polyphenols, flavonoids and glucosinolates). The chemical investigation showed a different composition between the two collection zones. While the total amounts of phenolics and flavonoids of the two samples were quite the same, their high-performance liquid chromatography profiles were very different. In both samples, the most abundant aglycone was quercetin which accounted for 60% of total flavonoids. Nuclear magnetic resonance data analysis allowed the identification of two compounds: 3,5-dicaffeoylquinic and 4,5-dicaffeoylquinic acids which represented 6.67% and 15.94%, respectively, of the total amount of flavonoids in sample 1. In sample 2, these two acids were still present, but their percentages were much less (2.20% and 1.71%, respectively). As far as we know, this is the first report about the presence of dicaffeoylquinic acids in Capparis. With regard to glucosinolate content, sample 1 showed a higher content of glucosinolates. In both samples, glucocapparin was the most abundant compound. Antioxidant activity of the methanolic C. sicula extracts using diphenyl picrylhydrazyl, β-carotene bleaching test and oxygen radical absorbance capacity showed that the sample 2 was more active than 1. As regards the inhibition of NO production, the extracts from sample 2 were more active than those from sample 1.

Naturally contaminated shellfish samples: quantification of diarrhetic shellfish poisoning toxins in unhydrolysed and hydrolysed extracts and cytotoxicity assessment

Contamination of shellfish from the Portuguese coast with diarrhetic shellfish poisoning (DSP) toxins is a recurrent event, with most of the commercial bivalves contaminated with high percentages of esters of okadaic acid (OA) and dinophysistoxin-2 (DTX2). This report describes the quantification of DSP toxins in unhydrolysed and hydrolysed extracts of several cockle and mussel samples naturally contaminated and the evaluation of their cytotoxicity profiles in V79 cells. The quantification of the acyl esters in the shellfish samples involved the cleavage of the ester bond through alkaline hydrolysis and the release of the parent toxins OA and DTX2. Unhydrolysed and hydrolysed extracts were then analyzed by liquid chromatography (LC) coupled with mass spectrometry (MS) for the detection and quantification of DSP toxins. The cytotoxicity of the analysed extracts was evaluated using the MTT reduction assay and compared with the cytotoxicity presented by different concentrations of OA standard (1-100 nM). OA exhibited marked cytotoxic effects and decreased cell viability in a dose dependent mode, with an IC₅₀ of 27 nM. The cytotoxicity pattern of unhydrolysed extracts was clearly dependent on the concentration of free toxins. Moreover, the cytotoxicity of the esterified toxins present was revealed after their conversion into free toxins by alkaline hydrolysis. For the hydrolysed extracts of cockles and mussels, the cytotoxicity presented was mainly related to the concentration of OA and DTX2.

Chemical composition and bioactivity of Citrus medica L. cv. Diamante essential oil obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction

The chemical composition of the essential oil of Citrus medica L. cv. Diamante peel obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction techniques was determined by GC/MS analysis. Forty-six components were fully characterised. Limonene and γ-terpinene were the major components of the oils obtained by hydrodistillation (HD) and cold-pressing (CP), while citropten was the major constituent in the oil obtained by supercritical carbon dioxide extraction (SFE). Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities were evaluated. The essential oil obtained by hydrodistillation exerted the highest inhibitory activity against BChE (IC₅₀ value of 154.6 µg mL⁻¹) and AChE (IC₅₀ value of 171.3 µg mL⁻¹. Interestingly, the oil obtained by cold-pressing exhibited a selective inhibitory activity against AChE. The essential oils have also been evaluated for the inhibition of NO production in LPS induced RAW 264.7 macrophages. The oil obtained by hydrodistillation exerted a significant inhibition of NO production with an IC₅₀ value of 17 µg mL⁻¹ (IC₅₀ of positive control 53 µg mL⁻¹).

Update on methodologies available for ciguatoxin determination: perspectives to confront the onset of ciguatera fish poisoning in Europe

Ciguatera fish poisoning (CFP) occurs mainly when humans ingest finfish contaminated with ciguatoxins (CTXs). The complexity and variability of such toxins have made it difficult to develop reliable methods to routinely monitor CFP with specificity and sensitivity. This review aims to describe the methodologies available for CTX detection, including those based on the toxicological, biochemical, chemical, and pharmaceutical properties of CTXs. Selecting any of these methodological approaches for routine monitoring of ciguatera may be dependent upon the applicability of the method. However, identifying a reference validation method for CTXs is a critical and urgent issue, and is dependent upon the availability of certified CTX standards and the coordinated action of laboratories. Reports of CFP cases in European hospitals have been described in several countries, and are mostly due to travel to CFP endemic areas. Additionally, the recent detection of the CTX-producing tropical genus Gambierdiscus in the eastern Atlantic Ocean of the northern hemisphere and in the Mediterranean Sea, as well as the confirmation of CFP in the Canary Islands and possibly in Madeira, constitute other reasons to study the onset of CFP in Europe [1]. The question of the possible contribution of climate change to the distribution of toxin-producing microalgae and ciguateric fish is raised. The impact of ciguatera onset on European Union (EU) policies will be discussed with respect to EU regulations on marine toxins in seafood. Critical analysis and availability of methodologies for CTX determination is required for a rapid response to suspected CFP cases and to conduct sound CFP risk analysis.

Biological methods for marine toxin detection

The presence of marine toxins in seafood poses a health risk to human consumers which has prompted the regulation of the maximum content of marine toxins in seafood in the legislations of many countries. Most marine toxin groups are detected by animal bioassays worldwide. Although this method has well known ethical and technical drawbacks, it is the official detection method for all regulated phycotoxins except domoic acid. Much effort by the scientific and regulatory communities has been focused on the development of alternative techniques that enable the substitution or reduction of bioassays; some of these have recently been included in the official detection method list. During the last two decades several biological methods including use of biosensors have been adapted for detection of marine toxins. The main advances in marine toxin detection using this kind of technique are reviewed. Biological methods offer interesting possibilities for reduction of the number of biosassays and a very promising future of new developments.

Metabolite profile and in vitro activities of Phagnalon saxatile (L.) Cass. relevant to treatment of Alzheimer's disease

The present study describes for the first time the in vitro properties (inhibition of NO production and anticholinesterase) of Phagnalon saxatile (L.) Cass. (Asteraceae). The methanolic extract showed antioxidant activity that was measured by DPPH assay and beta-carotene bleaching test. The same extract inhibited NO production in the murine monocytic macrophage cell line RAW 264.7. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition was assessed by modifications of Ellman's method. Purification of the MeOH extract of P. saxatile allowed the isolation of phenolic compounds. Among them, the compounds that most effectively inhibited lipopolysaccharide-induced NO production were caffeic acid and methylchlorogenic acid, with IC50 values of 7 microg/mL and 12 microg/mL, respectively. Luteolin and 3,5-dicaffeoylquinic acid exhibited the most promising activity against AChE with an IC50 of 25.2 and 54.5 microg/mL, respectively, while caffeic acid and luteolin exhibited higher activity against BChE with an IC50 of 32.2 and 37.2 microg/mL, respectively.

Synthesis, inhibition of NO production and antiproliferative activities of some indole derivatives

The synthesis and the biological evaluation of pyrano[3,2-e]indoles and their reaction intermediates are described. The compounds prepared were evaluated for their inhibition of NO production, antioxidant activity and also for their ability to inhibit in vitro the growth of four human tumor cell lines: large lung carcinoma (COR-L23), alveolar basal epithelial carcinoma (A549), amelanotic melanoma (C32) and melanoma (A375). The two reaction intermediates, 5a and 5b, showed the highest inhibition of NO production in murine monocytic macrophage (IC(50) = 1.1 microM and IC(50) = 2.3 microM respectively). Compound 5a was the most active against melanotic melanoma (IC(50) = 11.8 microM) while the other compounds exhibited weak cytotoxicity with IC(50) values >50 microM on all cell lines.

Use of biosensors as alternatives to current regulatory methods for marine biotoxins

Marine toxins are currently monitored by means of a bioassay that requires the use of many mice, which poses a technical and ethical problem in many countries. With the exception of domoic acid, there is a legal requirement for the presence of other toxins (yessotoxin, saxitoxin and analogs, okadaic acid and analogs, pectenotoxins and azaspiracids) in seafood to be controlled by bioassay, but other toxins, such as palytoxin, cyclic imines, ciguatera and tetrodotoxin are potentially present in European food and there are no legal requirements or technical approaches available to identify their presence. The need for alternative methods to the bioassay is clearly important, and biosensors have become in recent years a feasible alternative to animal sacrifice. This review will discuss the advantages and disadvantages of using biosensors as alternatives to animal assays for marine toxins, with particular focus on surface plasmon resonance (SPR) technology.

NG108-15 cell-based and protein phosphatase inhibition assays as alternative semiquantitative tools for the screening of lipophilic toxins in mussels. Okadaic acid detection

We report the application of a cell-based assay (CBA) using NG108-15 a hybridoma cell strain and a protein phosphatase inhibition-based assay (PPIA) as alternative toxicological or functional semiquantitative tools, respectively, for the screening of lipophilic toxins in mussels (Mytilusgalloprovincialis). Acetonic extracts were directly tested by CBA and PPIA but severe matrix effects were observed. As a solution, a simple 17-fraction protocol with solid-phase extraction (SPE) cartridges was optimised and applied as a previous step to the CBA or the PPIA. LC-MS/MS analyses were performed in parallel to determine the lipophilic toxins content in mussel extracts. Evaluation of the SPE protocol by LC-MS/MS showed okadaic acid (OA) recovery above 90% and negligible effects of mussel matrix on the SPE performance. The whole methods provided limits of detection of 47 and 45mug OA equivalents/kg for CBA and PPIA, respectively. The combined strategy permitted the identification of OA toxicity in two fractions, and allowed us to clearly distinguish between negative and positive samples, the latter being either OA-spiked or naturally-contaminated samples at levels equal or above the regulatory limit. The combination of fractioning with CBA or PPIA allows the quantification of the toxic and functional effects of samples above these concentrations.

Cytotoxic activity and inhibitory effect on nitric oxide production of triterpene saponins from the roots of Physospermum verticillatum (Waldst & Kit) (Apiaceae)

Three triterpene saponins isolated from the roots of Physospermum verticillatum and identified as saikosaponin a (1), buddlejasaponin IV (2), and songarosaponin D (3) were investigated in vitro for their cytotoxic activity against a panel of seven different cancer cell lines including ACHN, C32, Caco-2, COR-L23, A375, A549, and Huh-7D12 cell lines. The hydrolysis of sugar unit was performed on saikosaponin a (1) to obtain saikosapogenin a (4). All isolated saponins exhibited strong cytotoxic activity against COR-L23 cell line with IC(50) values ranged from 0.4 to 0.6 microM. A similar activity was recorded for saikogenin a (4). None of the tested compounds affected the proliferation of skin fibroblasts 142BR suggesting a selective action against cancer cells. Moreover, buddlejasaponin IV (2) and songarosaponin D (3) exerted significant inhibition of NO production in LPS induced RAW 264.7 macrophages with IC(50) of 4.2 and 10.4 microM, respectively.

Down-regulatory effect of usnic acid on nuclear factor-kappaB-dependent tumor necrosis factor-alpha and inducible nitric oxide synthase expression in lipopolysaccharide-stimulated macrophages RAW 264.7

The purpose of this study was to investigate the molecular mechanisms that are responsible for the antiinflammatory effect of usnic acid (UA). UA is one of the most common and abundant lichen metabolites. The present study examined the effects of UA on the tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages and the underlying molecular mechanisms. UA decreased the TNF-alpha level in LPS-stimulated RAW264.7 macrophages in dose-dependent manner, the IC(50) value was 12.8 microM. RT-PCR analysis indicated that it inhibited TNF-alpha mRNA expression. Furthermore, it inhibited NO production in LPS-activated RAW264.7 macrophages, the IC(50) value was 4.7 microM. Western blot analysis showed that UA attenuated LPS-induced synthesis of iNOS protein and nuclear translocation of NF-kappaB p65 in the macrophages, in parallel. UA also inhibited LPS-mediated I-kappaBalpha degradation. Taken together, this suggests that UA has an antiinflammatory effect by inhibiting TNF-alpha and iNOS expression, possibly through suppression of nuclear translocation of NF-kappaB p65 and I-kappaBalpha degradation.

Suitability of the Neuro-2a cell line for the detection of palytoxin and analogues (neurotoxic phycotoxins)

Palytoxin and related compounds are neurotoxic phycotoxins produced by benthic microalgae belonging to the genus Ostreopsis. For several years this family of phycotoxins has been posing a threat to human health since they can bioaccumulate in shellfish. With the aim of replacing current biological assays, such as the mouse or hemolytic assays, we investigated using the Neuro-2a neuroblastoma cell line to detect palytoxin and related compounds. Cell death induced by the effects of PlTX and analogues on Na+, K+-ATPase were measured using the 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT) assay for mitochondrial reductase activity as a surrogate for cell number. The specificity of the Neuro-2a cell-based assay for palytoxin detection was confirmed by using ouabain, which also acts on Na+, K+-ATPase. Pre-treatment of the Neuro-2a cells with ouabain minimizes the effects of palytoxin. The specificity of the Neuro-2a assay was confirmed by the finding that cell death was not detected when Neuro-2a cells were exposed to other phycotoxins with unrelated cellular targets. When the Neuro-2a assay was used to detect palytoxin in mussel extracts spiked with levels of palytoxin around the proposed regulatory value of 250 microg palytoxin/kg shellfish, a good correlation was observed between the levels found and the expected values. We conclude by proposing an experimental design for functional assays using the Neuro-2a cell line for the specific detection of four neurotoxic phycotoxin families: saxitoxins, brevetoxins, ciguatoxins and palytoxins.

Methanolic Extract of Cynara Cardunculus L. Inhibits Cell Proliferation and Bcr/Abl Expression in K562 Cell Line

Introduction: Chronic myeloid leukaemia (CML) is a myeloid neoplasm defined by the Bcr/Abl oncoprotein that is considered essential for leukaemogenesis and accumulation of neoplastic cells. Evidence exists showing that extracts of antichoke Cynara cardunculus L. (CCE) are able to inhibit cancer cell growth in vitro (1). In the present study we have investigated the antiproliferative effect of methanolic extract of CEE on K562 Bcr-Abl positive leukemia cell line. In addition we evaluated whether the extract of CEE also affects the mRNA levels of Bcr-Abl and p210 expression in this cell line.

Materials and Methods: Preparation of methanolic extract of CEE. The aerial parts of CEE were air dried until dryness at room temperature, cut into small pieces and then extracted with methanol through maceration (48 h for 3 times). The resultant total extracts were dried under reduced pressure and their weight was determined.

Cell culture. The K562 cells were grown in RPMI 1640 with L-glutamine supplemented with 10% (v/v) heat-inactivated FBS, 1% penicillin/streptomycin in humidified atmosphere of 5% CO2 at 37°C. In all experiments growing cells at optimal concentration were placed in 24 or 96 well plate and then treated with vehicle or 5–100–200 μg/ml methanolic extract of CEE. 48h after the treatment cultures were tested for proliferative activity, mRNA level of Bcr-Abl by RT-PCR and p210 protein expression by western blotting analysis.

Proliferative activity. Proliferative activity was determined using the MTT technique according to the method described by Tubaro et al. (1996). The assay was performed in triplicate and absorbance values at 550 nm were measured using a microplate reader.

RT-PCR Analysis. The total cellular mRNA was isolated from treated and control cells using an silica coloumns. Using equal amounts of the RNA from each sample, the cDNA was synthesized by Superscript VILO™ cDNA kit. PCR was performed using Platinum® Taq DNA polymerase and specific primers for t(9;22) p210 transcripts (b3a2): GAAGTGTTTCAGAAGCTTTCC (sense) and GTTTGGGCT-TCACACCATTCC (antisense). 35 amplification cycles were performed at 94°C for 30s, 55°C for 30s and 72°C for 1min. Gel electrophoresis and ethidium bromide staining was used to visualize the PCR products.

Western Blot Analysis. Cell pellets from control and treated cultures were lysed using lysis buffer with protease and phosphatase inhibitors. The proteins were then quantified and equal amounts (30 ug) were separated by SDS-PAGE and electro-blotted to nitrocellulose. After blocking procedure the blots were incubated with specific primary antibody against p210 protein and then challenged with specific horseradish peroxidase-conjugated secondary antibody. The reactive protein was visualized using an enhanced chemiluminescence detection system.

Results: The results have shown that treatment of K562 cell line with methanolic extract of CEE reduced cell viability in a dose-dependent fashion (IC50=41.7 μg/ml) as demonstrated by MTT assay. PCR and Western blot analysis revealed that the cell growth inhibition was associated to a dramatic decrease of mRNA levels of Bcr-Abl and to a significant reduction of p210 protein expression suggesting that the antiproliferative effect of methanolic extract of CEE likely due to the inhibition at transcriptional level of Bcr-Abl oncoprotein. Further studies are needed to better elucidate this mechanisms and to identify the compound of crude extract which is responsible of cancer growth suppression.

Immunomodulating activity of arabinogalactan and fucoidan in vitro

Many polysaccharides obtained from natural sources are considered to be biological response modifiers and have been shown to enhance various immune responses. Here, we investigated the immunomodulating effects of arabinogalactan (AG) and fucoidan (FU) in vitro. Mouse spleen lymphocytes became cytotoxic to tumor cells after culture with AG and FU at concentrations of 10-100 microg/mL. Also, AG and FU were mitogenic in spleen lymphocytes and peripheral macrophages. Macrophages treated with AG and FU (10-100 microg/mL) exhibited induced tumoricidal activity and increased phagocytosis, lysosomal enzyme activity, and production of nitrite, H2O2, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6. However, AG and FU had little effect on the level of IL-1beta. Thus, the tumoricidal effect of AG- and FU-activated macrophages appeared to be mainly mediated by production of free radicals (NO and H2O2) and cytokines (TNF-alpha and IL-6). These data suggest that AG and FU are activators of lymphocytes and macrophages. This property may contribute to their effectiveness in the immunoprevention of cancer.

Induction of apoptosis and cell cycle arrest by a chalcone panduratin A isolated from Kaempferia pandurata in androgen-independent human prostate cancer cells PC3 and DU145

Because of unsatisfactory treatment options for prostate cancer (CaP) there is a need to develop novel preventive approaches for this malignancy. One such strategy is through chemoprevention by the use of non-toxic dietary substances and botanical products. We have shown previously that panduratin A isolated from the extract of Kaempferia pandurata (Zingiberaceae) is a strong inhibitor of cyclooxygenase-2 in RAW264.7 cells and induces apoptosis in HT-29 cells. In the present study, we provide evidence that panduratin A treatment to androgen-independent human CaP cells PC3 and DU145 result in a time and dose-dependent inhibition of cell growth with an IC50 of 13.5-14 microM and no to little effect on normal human prostate epithelial cells. To define the mechanism of these anti-proliferative effects of panduratin A, we determined its effect on critical molecular events known to regulate the cell cycle and the apoptotic machinery. Annexin V/propidium iodide staining provided the evidence for the induction of apoptosis which was further confirmed by the observation of cleavage of poly (ADP-ribose) polymerase and degradation of acinus. Panduratin A treatment to cells was found to result in inhibition of procaspases 9, 8, 6 and 3 with significant increase in the ratio of Bax:Bcl-2, suggesting the involvement of a mitochondrial-dependent apoptotic pathway. Panduratin A-mediated apoptosis was accompanied with upregulation of Fas death receptor and TNF-related apoptosis-inducing ligand (TRAIL). Furthermore, cell cycle analysis using flow cytometry showed that panduratin A treatment of cells resulted in a G2/M arrest in a dose-dependent manner. The immunoblot analysis data revealed that in both cell lines panduratin A treatment resulted in a dose-dependent (i) induction of p21WAF1/Cip1 and p27Kip1, (ii) downregulation of cdks 2, 4 and 6 and (iii) decrease in cyclins D1 and E. These findings suggest that panduratin A may be an effective chemopreventive or therapeutic agent against CaP.

New Stilbenoids from Pholidota yunnanensis and Their Inhibitory Effects on Nitric Oxide Production

Six new stilbenoids, a (bibenzyldihydrophenanthrene) ether designated phoyunnanin D (1), a bis(dihydrophenanthrene) ether designated phoyunnanin E (2), and four stilbenes designated phoyunbene A-D (3-6), were isolated from the air-dried whole plant of Pholidota yunnanensis ROLFE. The new compounds were identified as 7-[2-(3-hydroxyphenethyl)-4-hydroxy-6-methoxyphenoxy]-4-hydroxy-2-methoxy-9,10-dihydrophenanthrene (1), 1-[(9,10-dihydro-4-hydroxy-2-methoxy-7-phenanthrenyl)oxy]-4,7-dihydroxy-2-methoxy-9,10-dihydrophenanthrene (2), trans-3,3'-dihydroxy-2',4',5-trimethoxystilbene (3), trans-3,4'-dihydroxy-2',3',5-trimethoxystilbene (4), trans-3,3'-dihydroxy-2',5-dimethoxystilbene (5), and trans-3-hydroxy-2',3',5-trimethoxystilbene (6) based on spectroscopic evidence. Furthermore, the inhibitory effects of compounds 1-6 on nitric oxide production in a murine macrophage-like cell line (RAW 264.7) activated by lipopolysaccharide and interferon-gamma were examined.

Effects of Morus alba leaf extract on the production of nitric oxide, prostaglandin E2 and cytokines in RAW264.7 macrophages

Morus alba leaf methanolic extract and its fractions (chloroform, butanol, and aqueous fractions) were found to inhibit NO production in LPS-activated RAW264.7 macrophages without an appreciable cytotoxic effect at concentration from 4 to 100 microg/ml. LPS-induced PGE2 production was significantly reduced only by butanol fraction. In addition, M. alba leaf extract and its fractions significantly decreased the production of TNF-alpha. These findings suggest that M. alba leaf extract seems to be able in suppressing inflammatory mediators. Moreover, the inhibitory activities on COX-2 and iNOS of its butanol fraction are warranted for further elucidation of active principles for development of new antiinflammatory agents.

Screening of Indonesian medicinal plants for inhibitor activity on nitric oxide production of RAW264.7 cells and antioxidant activity

Traditional Indonesian medicinal plants were screened for their inhibitory effects on the nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and for the antioxidant activity through the evaluation of free radical scavenging effect and reducing power. The results of screening indicated that 50 methanolic extracts inhibited (>50%) lipopolysaccharides (LPS)-induced NO release from RAW264.7 cells at 50 microg/ml, with 18 having greater than 100% inhibition. At 200 microg/ml, 61 methanol extracts exhibited inhibitory activity (>50%), with 45 showing greater than 100% inhibition. In addition, the free radical scavenging effects of 6 methanolic extracts were found to be more than 50% for extract concentration of 0.5 mug/ml. The results indicate that the extracts contain active compounds that inhibit NO release and scavenge free radical.

Cytotoxic and cytoskeletal effects of azaspiracid-1 on mammalian cell lines

Azaspiracid-1 (AZA-1) is a newly identified phycotoxin reported to accumulate in molluscs from several northern European countries and documented to have caused severe human intoxications. The mechanism of action of AZA-1 is unknown. Our initial investigations have shown that AZA-1 is cytotoxic to a range of cell types. Cytotoxicity was evident in all seven cell types tested, suggesting a broad-spectrum mode of action, and was both time- and concentration-dependent. However, AZA-1 took an unusually long time (>24 h) to cause complete cytotoxicity in most cell types, with the exception of the rat pituitary GH(4)C(1). Extended exposure times did not always lower the EC(50) value for a given cell line, but always resulted in more complete cytotoxicity over a very narrow concentration range. The Jurkat cell line (human lymphocyte T) appeared to be very sensitive to AZA-1, although the EC(50) values (24-72 h) for all the cell types were in the low nanomolar range (0.9-16.8 nM). The effect of AZA-1 on membrane integrity was tested on Jurkat cells and these data confirm our visual observations of cytotoxicity and necrotic cell lysis following exposure of Jurkat cells to AZA-1 and suggest that AZA-1 has some properties unique among marine algal toxins. Additionally, there were dramatic effects of AZA-1 on the arrangement of F-actin with the concurrent loss of pseudopodia, cytoplasmic extensions that function in mobility and chemotaxis. Although these phycotoxin-specific effects of AZA-1 suggest a possible site of action, further work using cell-based approaches is needed to determine the precise mode of action of AZA-1.

Functional assays in marine biotoxin detection

The contamination of seafood by algal toxins regularly affects animals living in several areas of the world, and the number of toxic phycotoxins which are being characterized is steadily increasing. The extreme dynamics characterizing the field of algal toxins has stimulated the development of tools to be implemented in the monitoring of contamination of seafood by individual toxin classes. Under these circumstances, functional assays which can encompass the analytical potential of chemical methods and the predictive features of biological tests are sought. A variety of functional assays for the detection of phycotoxins has been developed in the last 20 years, and the analysis of their features reveals that their specificity is related to the hierarchical level of the biological response to the toxin that has been exploited for its detection. Ideally, analytical methods which could allow accurate estimates of the overall toxicity of multiple classes of toxins in a single procedure would provide the best means for the highest standards in consumer protection and the most rational and economical tools in the management of risks posed by phycotoxins in a wider scale. The achievement of a "systemic functional assay for marine biotoxins" does not appear to be at hand, but its inclusion among the foreseeable events is fully justified by the new research tools and approaches which have become available for the high throughput analysis of entire molecular domains at the cellular level.