China
Africa
Explore chapters and articles related to this topic
Potential application of Bioactive Compounds from agroindustrial Waste in the Cosmetic Industry
Published in Quan V. Vuong, Utilisation of Bioactive Compounds from Agricultural and Food Waste, 2017
Francisca Rodrigues, Ana F. Vinha, M. Antónia Nunes, M. Beatriz P. P. Oliveira
Free radicals are highly reactive molecules with unpaired electrons whose formation is widely accepted as the pivotal mechanism that leads to skin aging. Oxidative stress happens when the balance between production and elimination of reactive oxygen species (ROS), reactive nitrogen species (RNS) and reactive sulfur species (RSS) is compromised, leading to overproduction of oxidative species (Craft et al. 2012). The main targets of pro-oxidants, like ROS, RNS and RSS are proteins, DNA and RNA molecules, sugars and lipids (Craft et al. 2012). The damaging effects of these reactive species are induced internally (during normal metabolism) and externally, through various oxidative stresses, such as ultraviolet (UV) light. Indeed, the production of free radicals increases with age, while the endogenous defense mechanisms decrease, leading to accelerated aging. One of the skin’s defense mechanisms is antioxidant defense where enzymes and other antioxidant substances react directly with the radical species, preventing them from reaching their biological target. Antioxidant substances have the ability to bind free radicals and prevent the therapy of various skin diseases, as well as slowing the skin’s aging process. The topical application of antioxidants, such as vitamin C or E, coenzyme Q10 and polyphenolic compounds may strengthen the skin’s endogenous protection system, protecting it from the harmful effects of ROS and oxidative damage to the skin. Phenolic compounds are involved in the defense process against deleterious oxidative damage, thus protecting against oxidative stress-related diseases. This can result in visible signs of healthy, more vibrant skin. Three of the better-known bioflavonoids— quercetin, hesperidin, and rutin—have intrigued researchers with their abilities to prevent and reverse wrinkles, reduce the appearance of age spots and fight spider veins (Zhu and Gao 2008).
Near-Infrared Organic Materials for Biological Applications
Published in Song Sun, Wei Tan, Su-Huai Wei, Emergent Micro- and Nanomaterials for Optical, Infrared, and Terahertz Applications, 2023
To date, a series of NIR fluorescent probes based on quantum dots, carbon nanomaterials, rare-earth doped nanoparticles, etc. have been studied extensively. However, NIR organic fluorescent probes are more fascinating because of their defined molecular structures, easy derivatization, high fluorescence quantum yield, and most importantly, low bio-toxicities. As a representative, cyanine dyes are quite attractive as NIR absorption and emission units in biological probes (labeling and sensing), in which the most famous one is indocyanine green (ICG), which has been approved as a fluorescent contrast for human use by the United States Food and Drug Administration (FDA) and European medicines agency (EMA) [71]. So far, a variety of biological analytes and parameters can be monitored by NIR fluorescent probes, which include metal ions, reactive oxygen species (ROS), reactive nitrogen species (RNS) reactive sulfur species (RSS, like biothiols and H2S), pH, gas, enzymes, amino acids, temperature, viscosity, etc., providing molecular tools for deciphering biological activities or pathogenesis in vitro or in vivo [72–74]. For example, Zhang and co-workers synthesized a series of pentamethine cyanine NIR fluorophores with significant anti-quenching feature, as well as superior photostability [75]. These dyes absorb and emit light at wavelengths beyond 1000 nm, whose intensities are responsive to pH variations, thus affording noninvasive ratiometric NIR-II fluorescence sensing of pH which is suitable for sensing pH fluctuations in deep tissues in vivo. Another kind of widely used NIR fluorophores for molecular probes are BODIPY derivatives. Their photophysical properties can be dramatically changed by different substitutions on their conjugated core, therefore, BODIPY-based probes can sensitively respond to external reagents like H2S, GSH, etc., in fluorescence “off-on” or ratiometric modes, which can be potentially used to monitor the redox homeostasis of biological systems [76].
Virtual screening of sulfur compounds of Allium against coronavirus proteases: E-Ajoene is a potential dual protease targeting covalent inhibitor
Published in Journal of Sulfur Chemistry, 2023
Shamasoddin Shekh, Smriti Moi, Konkallu Hanumae Gowd
Figure 1 shows the location in the genome domain and crystal structures of PLpro and Mpro of SARS CoV-2. These two proteases are cysteine proteases and contain cysteine-free thiol at the active site motif. In the case of PLpro the active site constitutes catalytic triad motif Cys111, His272, and Asp286. In the case of Mpro the active site contains catalytic dyad motif His41 and Cys145 (Figure 1). The presence of cysteine-free thiol is evident in both PLpro and Mpro. Figure 2 shows the major sulfur compounds derived from garlic and onion species. These sulfur compounds contain both reactive and non-reactive sulfur species. The reactive sulfur species contain groups such as disulfides, thiosulfinates, trisulfides, and tetrasulfides. The non-reactive sulfur species contain groups such as thioether and sulfoxide. The 52 sulfur compounds were virtually screened using the conventional docking method to assess the binding affinity to both Mpro and PLpro as described in the methods section.