Developing new green solvents is one of the key subjects in Green Chemistry. Ionic liquids (ILs) and deep eutectic solvents, thus, have been paid great attention to replace current harsh organic solvents and have been applied to many chemical processing such as extraction and synthesis. However, current ionic liquids and deep eutectic solvents have still limitations to be applied to a real chemical industry due to toxicity against human and environment and high cost of ILs and solid state of most deep eutectic solvents at room temperature. Recently we discovered that many plant abundant primary metabolites changed their state from solid to liquid when they were mixed in proper ratio. This finding made us hypothesize that natural deep eutectic solvents (NADES) play a role as alternative media to water in living organisms and tested a wide range of natural products, which resulted in discovery of over 100 NADES from nature. In order to prove deep eutectic feature the interaction between the molecules was investigated by nuclear magnetic resonance spectroscopy. All the tested NADES show clear hydrogen bonding between components. As next step physical properties of NADES such as water activity, density, viscosity, polarity and thermal properties were measured as well as the effect of water on the physical properties. In the last stage the novel NADES were applied to the solubilization of wide range of biomolecules such as non-water soluble bioactive natural products, gluten, starch, and DNA. In most cases the solubility of the biomolecules evaluated in this study was greatly higher than water. Based on the results the novel NADES may be expected as potential green solvents at room temperature in diverse fields of chemistry.

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Mixtures of solid chemicals may become liquid under certain conditions. These liquids are characterized by the formation of strong ionic (ionic liquids) or hydrogen bonds (deep eutectic solvents). Due to their extremely low vapor pressure, they are now widely used in polymer chemistry and synthetic organic chemistry, yet little attention has been paid to their use as extraction solvents of natural products. This review summarizes the preparation of ionic liquids and deep eutectic solvents with natural product components and recent progress in their applications to the extraction and analysis of natural products as well as the recovery of extracted compounds from their extracts. Additionally, various factors affecting extraction features of ionic liquids and deep eutectic solvents, as well as potential useful technologies including microwave and ultrasound to increase the extraction efficiency, are discussed.

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Accumulation and growth inhibition of Cu to fresh water alga (Scenedesmus subspicatus 86.81 SAG) and the influences of ethylenediaminetetraacetic acid (EDTA) and fulvic acid (FA) were examined. These results demonstrated that both EDTA and FA could reduce toxicity of Cu to alga by the way of preventing Cu from being adsorbed by cell wall of alga. When dissolved Cu (Cu dissolved ), extracellular Cu (Cu extracellular ), and intracellular Cu (Cu intracellular ) were differentiated, our results showed that the concentration level of extracellular Cu ([Cu extracellular ]) was a good indicator for measuring the toxic effects of Cu on alga growth in complex matrix. Either in the absence or in the presence of EDTA and FA, the concentration of intracellular Cu increased to 0.6 Á/1.5 )/10 (8 mM per cell when the growth inhibition reached to about 50%. We found that the acute toxicity of copper on unicellular alga could be interpreted by its accumulation at a discrete site or biotic ligand at alga cell wall and critical accumulation of Cu associated with EC 50 was determined to be 1 )/10 (8 mM per cell. Therefore, the Biotic Ligand Model (BML) could be extended to predict the influence of copper on growth inhibition of alga. #

Drug delivery systems (DDS) based on poly (lactide-co-glycolide) (PLGA) microspheres and nanospheres have been separately studied in previous works as a means of delivering bioactive compounds over an extended period of time. In the present study, two DDS having different sizes of the PLGA spheres were compared in morphology, drug (dexamethasone) loading efficiency and drug release kinetics in order to investigate their feasibility with regard to production of medical combination devices for orthopedic applications. The loaded PLGA spheres have been produced by the oil-in-water emulsion/solvent evaporation method following two different schemes. Their morphology was assessed by scanning electron microscopy and the drug release was monitored in phosphate buffer saline solution at 37 degrees C for 550 h using high performance liquid chromatography. The synthesis schemes used produced spheres with two different and reproducible size ranges (20 +/- 10 and 1.0 +/- 0.4 microm) having a smooth outer surface and regular shape. The drug loading efficiency of the 1.0 microm spheres was found to be 11% as compared to just 1% for the 20 microm spheres. Over the 550 h release period, the larger spheres (diameter 20 +/- 10 microm) released 90% of the encapsulated dexamethasone in an approximately linear fashion whilst the relatively small spheres (diameter 1.0 +/- 0.4 microm) released only 30% of the initially loaded dexamethasone, from which 20% within the first 25 h. The changes observed were mainly attributed to the difference in surface area between the two types of spheres as the surface texture of both systems was visibly similar. As the surface area per unit volume increases in the synthesis mixture, as is the case for the 1.0 microm spheres formulation, the amount of polymer-water interfaces increases allowing more dexamethasone to be encapsulated by the emerging polymer spheres. Similarly, during the release phase, as the surface area per unit volume increases, the rate of inclusion of water into the polymer increases, permitting faster diffusion of dexamethasone.

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