Removal of cadmium or lead from polluted water by biological amphiphiles

Tannic Acid and Tea Prevents the Accumulation of Lead and Cadmium in the Lungs, Heart and Brain of Adolescent Male Wistar Rats—Possible Therapeutic Option

The protective effect of tannic acid and tea solutions on the lungs, hearts and brains of adolescent Wistar rats exposed to Pb and Cd was studied. Metals were administered with feed (7 mg Cd and 50 mg Pb/kg). Two experiments were carried. Experiment 1 aimed to determine the level of tannic acid (TA), most effectively reducing the adverse impact of Pb and Cd on the organs of adolescent rats (aged 5 weeks, weighing 169.3 ± 14.7 g) during combined exposure. TA was administered with drink (0, 0.5, 1, 1.5, 2 or 2.5% solutions). In Experiment 2, adolescent rats (aged 6 weeks, weighing 210.6 ± 12.1 g) received an aqueous solutions of black, green, red or white teas. TA and teas had a positive effect on reducing the accumulation of Cd in the organs. The results obtained suggest that long-term continuing administration of TA increases its effectiveness as a chelator for Pb. A 2% TA and white tea solution proved to be the most effective. In the analyzed tissues, increased activity of SOD and CAT was recorded as a result of the use of the TA and teas; thus, they can efficiently prevent the prooxidant effect of toxic metals.

Removal of hazardous ions from aqueous solutions: Current methods, with a focus on green ion flotation

Hazardous ions, like those of heavy metals, cause significant health and environmental problems when they are discharged into water resources naturally or through various industrial processes. Removing these ions from water is of significant importance in the provision of high-quality water for drinking and agricultural usage. This work discusses current techniques that are frequently used for the removal of heavy-metal ions from aqueous solutions by absorption, particularly the use of biodegradable surfactants in ion flotation. Certain new surfactants promise high efficiency in their use in the ion-flotation process and in their application in industrial-water treatment to remove heavy metals. As an example, this work demonstrates the high efficiency of surfactants based on an amino-acid (L-cysteine) in removing a range of heavy-metal ions in a simple, single-stage ion-flotation process. High foaming ability, the ability to operate in various temperatures and pHs, decomposing into natural products and high binding affinity for heavy-metal ions make the cysteine-based surfactants a highly suitable compound to replace current commercial surfactants in ion- and froth-flotation processes. Removal of particular ions can also be achieved in ion flotation; a suitable choice of parameters, such as pH and surfactant concentration, favours the surfactant binding to those ions. Further intensive work is required to develop an optimal process to recover valuable elements from waste solutions.

Production of spiculisporic acid by Talaromyces trachyspermus in fed-batch bioreactor culture

Spiculisporic acid (SA) is a fatty acid-type biosurfactant with one lactone ring and two carboxyl groups. It has been used in metal removers and cosmetics, because of its low propensity to cause irritation to the skin, its anti-bacterial properties, and high surface activity. In the present study, we report an effective method for producing SA by selecting a high-producing strain and investigating the effective medium components, conditions, and environments for its culture. Among the 11 kinds of Talaromyces species, T. trachyspermus NBRC 32238 showed the highest production of a crystalline substance, which was determined to be SA using NMR. The strain was able to produce SA under acidic conditions from hexoses, pentoses, and disaccharides, with glucose and sucrose serving as the most appropriate substrates. Investigation of nitrogen sources and trace metal ions revealed meat extract and FeCl3 as components that promoted SA production. Upon comparing the two types of cultures with glucose in a baffle flask or aeration bioreactor, SA production was found to be slightly higher in the flask than in the reactor. In the bioreactor culture, sucrose was found to be an appropriate substrate for SA production, as compared to glucose, because with sucrose, the lag time until the start of SA production was shortened. Finally, fed-batch culture with sucrose resulted in 60 g/L of SA, with a total yield of 0.22 g SA/g sucrose and a productivity of 6.6 g/L/day.

Use of Dietary Components to Reduce the Bioaccessibility and Bioavailability of Cadmium in Rice

Reducing Cd bioavailability in the systemic circulation is an alternative strategy to reduce Cd exposure. The influence of 39 dietary components on Cd bioaccessibility in water or rice was determined using an in vitro gastrointestinal model, following which an in vivo bioassay was used to determine the most effective components on Cd bioavailability in rice. The results showed that several components significantly reduced the solubility of Cd (10-98%) in the intestinal phase. Tannic acid, TiO₂, zinc gluconate, CaCl₂, and proanthocyanidins were the most effective in decreasing Cd bioaccessibility in rice, with reductions of 93-97, 54-61, 32-49, 24-32, and 11-14%, respectively. Upon adding the dietary components, the reduction rates of the Cd-relative bioavailability (Cd-RBA) were 20-58 and 10-31% in the kidneys and the liver, respectively. The results may have important implications for reducing health risks associated with Cd exposure via consumption of rice.

The effect of tannic acid on bone mechanical and geometric properties, bone density, and trabecular histomorphometry as well as the morphology of articular and growth cartilages in rats co-exposed to cadmium and lead is dose dependent

Cadmium (Cd) and lead (Pb) are toxic elements that accumulate to the largest extent in bones. Rats were used to investigate whether tannic acid (TA; 0.5%, 1.0%, 1.5%. 2.0%, or 2.5%) would have a protective effect on the structure and properties of bones in the case of exposure to Cd and Pb (diet: 7 mg Cd/kg and 50 mg Pb/kg) for 6 weeks. The effects of administration of TA in Cd- and Pb-poisoned rats on bone characteristics and the morphology of articular and growth cartilages were determined. All the rats administered Cd and Pb had an enhanced Cd and Pb concentration in blood plasma and bone and reduced bone Ca content irrespective of the TA administration. Cd and Pb alone reduced the mechanical endurance and histomorphometric parameters of trabecular bone and the thickness of the growth plate and articular cartilage. Tannic acid improved cancellous bone parameters in the rat exposed to Cd and Pb. A diet rich in TA improved articular cartilage constituents in heavy metal-poisoned rats. These results suggest that alimentary TA supplementation can counteract in a dose-dependent manner some of the destructive changes evoked by Cd and Pb possibly by reducing the exposure.

Micelles as Soil and Water Decontamination Agents

Contaminated soil and water pose a serious threat to human health and ecosystem. For the treatment of industrial effluents or minimizing their detrimental effects, preventive and remedial approaches must be adopted prior to the occurrence of any severe environmental, health, or safety hazard. Conventional treatment methods of wastewater are insufficient, complicated, and expensive. Therefore, a method that could use environmentally friendly surfactants for the simultaneous removal of both organic and inorganic contaminants from wastewater is deemed a smart approach. Surfactants containing potential donor ligands can coordinate with metal ions, and thus such compounds can be used for the removal of toxic metals and organometallic compounds from aqueous systems. Surfactants form host-guest complexes with the hydrophobic contaminants of water and soil by a mechanism involving the encapsulation of hydrophobes into the self-assembled aggregates (micelles) of surfactants. However, because undefined amounts of surfactants may be released into the aqueous systems, attention must be paid to their own environmental risks as well. Moreover, surfactant remediation methods must be carefully analyzed in the laboratory before field implementation. The use of biosurfactants is the best choice for the removal of water toxins as such surfactants are associated with the characteristics of biodegradability, versatility, recovery, and reuse. This Review is focused on the currently employed surfactant-based soil and wastewater treatment technologies owing to their critical role in the implementation of certain solutions for controlling pollution level, which is necessary to protect human health and ensure the quality standard of the aquatic environment.

Dietary Strategies To Reduce the Bioaccessibility of Arsenic from Food Matrices

The main route of exposure to arsenic (As) is the consumption of water and foods, in which the forms with greatest toxicity are inorganic As and dimethylarsinic acid, DMA(V). The objective of this study was to search for dietary components that reduce the bioaccessibility of As from food and water, in order to reduce the amount of As available for absorption. For this purpose, 35 compounds were assayed by use of a static in vitro model of gastrointestinal digestion. Sulfates of Fe(II) and Fe(III) reduced the solubility of inorganic As (86-99%) and DMA(V) in aqueous solution (40-66%). This reduction was also observed in rice (100%) and seaweed (60%). Aluminum, titanium, and tannic acid also reduced the bioaccessibility of As from food (42-70%). These data show that the use of dietary components may be a good strategy to reduce the entry of As into systemic circulation.

Protective effect of tannic acid on the brain of adult rats exposed to cadmium and lead

Chronic exposure to Cd and Pb causes brain damage. Tannic acid (TA) is a very efficient chelator for metals. The effect of exposure to Cd and/or Pb and TA on the rats' brain were studied. Two experiments were carried. In experiment no. 1 metals were administered with feed (7mg Cd and 50mgPb/kg) and TA with drink (0, 0.5, 1, 1.5, 2 or 2.5% solutions). In experiment no. 2, rats received an aqueous solutions of [Cd (7 or 14mg/L) or Pb (50 or 100mg/L)] or 2% TA, alternatively every 7 days. In both experiments, TA had a positive effect only on reducing the accumulation of Cd. Exposure to metals resulted in an decrease of superoxide dismutase and catalase activity, whereas TA administration increased those. The results suggests that TA are more effective if taken parallel to food contaminated by Cd, and their effectiveness is higher if their intake is long-term.

Spiculisporic acids B–D, three new γ-butenolide derivatives from a sea urchin-derived fungus Aspergillus sp. HDf2

Three new γ-butenolide derivatives 1–3, named spiculisporic acids B–D, were isolated from the culture of Aspergillus sp. HDf2, a marine-derived fungus that resides in the sea urchin, Anthocidaris crassispina. The structures of 1–3 were elucidated on the basis of spectroscopic methods, including MS and 2D NMR techniques. Their in vitro cytotoxic activities against two cell lines (SGC-7901, human gastric adenocarcinoma and SPC-A-1, human lung adenocarcinoma) and inhibitory activities against Staphylococcus aureus ATCC 51650 were investigated.

The first enantioselective organocatalytic Mukaiyama-Michael reaction: a direct method for the synthesis of enantioenriched gamma-butenolide architecture

The first enantioselective organocatalytic Mukaiyama-Michael reaction using alpha,beta-unsaturated aldehydes has been accomplished. The use of iminium catalysis has provided a new strategy for the enantioselective addition of 2-silyloxy furans to unsaturated aldehydes to generate a variety of butenolide systems, an important chiral synthon found among many natural isolates. The (2S,5S)-5-benzyl-2-tert-butyl-imidazolidinone amine catalyst has been found to mediate the conjugate addition of a wide variety of substituted and unsubstituted silyloxy furans to unsaturated aldehydes. A diverse range of aldehyde substrates can be accommodated in this new organocatalytic transformation. Application of this new asymmetric technology to the enantioselective total synthesis of spiculisporic acid and the corresponding 5-epi-spiculisporic acid analogue is also discussed.