Biohydrogels, composed of naturally occurring biopolymers are typically preferred over their synthetic analogues in bioapplications thanks to their biocompatibility, bioactivity, mechanical or degradation properties. Shaping biohydrogels on the single-cell length scales (micrometers) is a key ability needed to create bioequivalent artificial cell/tissue constructs and cannot be achieved with current methods. This work introduces a method for photolithographic synthesis of arbitrarily shaped microgels composed purely of a biopolymer of choice. The biopolymer is mixed with a sacrificial photocrosslinkable polymer, and the mixture is photocrosslinked in a lithographic process, yielding anisotropic microgels with the biopolymer entrapped in the network. Subsequent ionic or covalent biopolymer crosslinking followed by template cleavage yields a microgel composed purely of a biopolymer with the 3D shape dictated by the photocrosslinking process. Method feasibility is demonstrated with two model polysaccharide biopolymers (alginate, chitosan) using suitable crosslinking methods. Next, alginate microgels were used as microtaggants on a pharmaceutical oral solid dose formulation to prevent its counterfeiting. Since the alginate is approved as an additive in the food and pharmaceutical industries, the presented tagging system can be implemented in practical use much easier than systems comprising synthetic polymers.
Valerian is used to treat sleeping disorders, restlessness and anxiety, but it seemsonly to work when taken over long periods (several weeks). Some studies have demonstrated that valerian extracts interact with the GABA and benzodiazepine receptors. Valerian is also used traditionally to treat gastrointestinal pain and spastic colitis. There are no long term safety studies. Valerian contains over 150 chemical constituents and many of them are physiologically active, mainly pyridine alkaloids, some organic acids and terpenes, especially the so called valepotriates, esterified iridoid-monoterpenes. As valepotriates may be potential mutagens, valerian should only be used after consultation with a physician. Valerian medication is sometimes recommended as first line treatment when the benefit-risk relation requires it and is often indicated as transition medication during the discontinuation processes involving bromazepam, clonazepam and diazepam, among others.
- MeSH
- alkaloidy farmakologie klasifikace terapeutické užití MeSH
- analgetika terapeutické užití MeSH
- antikonvulziva terapeutické užití MeSH
- anxiolytika terapeutické užití MeSH
- experimenty na zvířatech MeSH
- hypnotika a sedativa terapeutické užití MeSH
- iridoidy chemie MeSH
- kozlík (rostlina) chemie MeSH
- kyseliny pentanové chemie škodlivé účinky terapeutické užití MeSH
- lidé MeSH
- rostlinné extrakty chemie MeSH
- rostlinné přípravky aplikace a dávkování škodlivé účinky terapeutické užití MeSH
- Valerianaceae chemie klasifikace MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
A novel, fast, and simple capillary electrophoresis method has been developed for the analysis of gentisin, isogentisin, and amarogentin in roots of Gentiana lutea (yellow gentian), an herb traditionally used as gastric stimulant. Gentisin and isogentisin are xanthones showing potent inhibition of monoamine oxidase type A and B, amarogentin represents one of the bitter principles of Gentiana, responsible for its gastric-roborant effects. Optimal CE-separation conditions comprise a 100 mM sodium tetraborate buffer of pH 9.3, containing 10 mM beta-cyclodextrin as additive; optimum temperature and applied voltage were found to be 30 degrees C and 25 kV, respectively. Direct diode array detection at 260 nm (gentisin, isogentisin) and 242 nm (amarogentin) was performed, and the required analysis time was only 11 min. The developed method was validated for linearity, sensitivity, precision, and accuracy, and utilized to assay several commercially available G. lutea samples. Quantitative data obtained with the developed CE method are compared with HPLC results, and the advantages of each approach are discussed.
