We used a delplot analysis and mechanistic considerations to develop a reaction network for conditions relevant to hydrothermal liquefaction of microalgae. Studied compounds included a estrogens and related steroids with an aromatic ring A and a hydroxy group on ring D; b Δ4-3-ketosteroids with a hydroxy group on ring D; c cholesterol and polyenic cholestanes; d bile acids. The same extract was also found to be almost 37-fold more selective against A-549 vs. Exploration of anti-inflammatory phytochemicals has received tremendous attention worldwide owing to the rapid increase in inflammatory diseases. Burchard, Salkowski and Zak color reactions tests indicated the presence of sterol compounds.
According to Wieland and Weil, the reaction results in the formation of a green-blue colored product, a sulphonic acid derivative of cholesterilene, which indicates the presence of cholesterol. Sterols in the shallow sediments are relatively enriched in 13 C compared to those from lower within the core. W China was studied to reveal the possible interference between diagenesis and climate signals. The Liebermann-Burchard test involves observing the reaction of cholesterol dissolved in chloroform with acetic anhydride and two drops of concentrated sulphuric acid. Repetition of this desaturation process leads to polyenes and ultimately to aromatic steroids. The results were expressed as 'mg cholesterol per 100 g of sample' and 'mg cholesterol per g of non-fat dry solid' on wet and dry bases, respectively.
In this study, the effect of different cooking procedures on the cholesterol, fat, and moisture contents on wet and dry bases of selected meat products was investigated. Discussion and conclusion: The screened extract may inspire a search for novel anticholinesterase therapeutic agent s potentially used in the treatment of Alzheimer's disease. Incorporating this step into the typical L-B method can increase the L-B sensitivity for cholesterol by several fold. A 45 cm long core from Zabuye Salt Lake Tibetan Plateau, S. The major reaction pathways do not involve cholestadienes, i-steroids, or cholesterol dimers, as proposed previously.
In vitro anti-tumour and anti-radical activities of the acetone extract of the freshwater sponge Ochridaspongia rotunda were the subject of this study. The absorption maxima observed immediately after the preparation of the solution and those observed after standing for various times at room temperature were correlated with the chemical species presumed to be produced in strong acids. A method was developed to study the correspondence of color change with structural change of the polyenyl cation in the color reaction of cholesterol in strong acid. Similar bridged species are also involved in many cation rearrangements. Cholesterol content of meat products was determined colorimetrically by the modified Liebermann-Burchard method Abel et al. Fourth, the sterol content in the extracts was analyzed with the Liebermann- Burchard test as described by Xiong et al.
These studies further suggest that the colored species observed in these two systems are enylic carbonium ions formed by protonation of the parent polyenes. Compared to marine species from all kingdoms, freshwater species have been highly neglected. The course of reaction is guided by hyperconjugation of the carbocationic 2p orbital with parallel C-C and C-H bonds. The green-blue color of the product is due to the interaction of the hydroxyl group of cholesterol with the reagent. The serum cholesterol level, which is considered a risk factor for cardiovascular disease, reportedly increases with higher intake of saturated fats and cholesterol.
Steroids, including sterols and sterenes, dominate the soluble organic matter in these cores. A solvent extraction procedure is described for specifically converting cholesterol to 3,5-cholestadiene. Oxidation potentials were found to be ca + 1. We investigated the reaction of cholesterol, a model compound for sterols in microalgae, in high-temperature water at 300, 325, and 350 °C. Liebermann-Burchard method was used to evaluate the sterol content of the ethanol extracts; cholesterol was used as the calibration standard Xiong et al. Liebermann-Burchard reagent, as prepared by Liebermann and Burchard, is used in a chemistry laboratory to detect cholesterol.
Differences among these 3 profiles were attributed to ring strain, steric effects, and proton affinity. The relative abundance of C 27 sterol to the C 29 sterols decreases with depth, resulting in a predominance of C 29 sterols at the bottom section of this core. Cholesta-3,5-diene was the only primary product, formed via dehydration of cholesterol. Preliminary results show that other steroids, e. The exact me- chanism and structure of the products of both chemical and electro- chemical reaction steps are under investigation. The effects of rate of carbonium ion formation and sulfuric acid concentration on sensitivity and color stability are discussed.
We thank Alemka Kisic for supplying purified cholesterol. Herein, a novel way of electrochemical oxidation of primary bile acids is reported, involving an initial acid-induced dehydration step, as confirmed by capillary electrophoresis—mass spectrometry, thereby extending the electrochemical activity of the steroid core. Furthermore, the Ames test revealed no sign of mutagenicity at any concentration tested. Cholesta-2,4-diene and cholesta-4,6-diene likely formed from cholesta-3,5-diene by double-bond migration. We report conversion and product molar yields for each reaction condition. Sterols are protonated in strongly acidic media and form carbocations which are in equilibrium with olefins. Allylic carbocations formed absorb in the 300- to 320-nm range.
In the present study, authors evaluate the anticancer effects of eight crude extracts from 70% ethanol extracts of soft corals collected in Jeju Island, South Korea. Nevertheless, the classical polyene cation model is not excluded for Salkowski conditions sulfuric acid , which immediately generate considerable amounts of cholesta-3,5-diene. . However, all other three extracts showed a cytotoxic effect. Most quantum mechanical studies of triterpene synthesis have been done on small models. Further, oxidative properties of perchloric acid itself have to be considered together with the fact, that beside the final products of dehydration reaction the in- termediates can undergo electrochemical oxidation.