10.1021/ac034876a
The study presents the development of a biosensor-based assay for the quantification of riboflavin (Rf) in milk samples using surface plasmon resonance (SPR) technology. The assay involves the indirect measurement of Rf by detecting the excess of riboflavin binding protein (RBP) that remains free after complexation with Rf molecules originally present in the sample. The sensor chip is modified with covalently immobilized Rf to bind the excess RBP. The method involves a chemical modification to introduce a reactive ester group on the Rf molecule for immobilization on the chip surface. Calibration solutions are prepared by mixing Rf standard solutions with an optimized concentration of RBP, and the Rf content in milk samples is measured by comparing the response against the calibration. The results are comparable to those obtained from an official HPLC-fluorescence procedure, with a limit of quantification determined to be 234 μg/L and a limit of detection to 70 μg/L. The study demonstrates the potential of SPR-based biosensors as a competitive alternative to traditional analytical techniques for the determination of riboflavin in food samples.
10.1016/j.tetlet.2009.06.032
The study focuses on the cross metathesis (CM) reactions of β-carotene with electron-deficient dienes, specifically using the Hoveyda second generation catalyst, to synthesize retinoids, which are compounds related to vitamin A and play a crucial role in various biological processes such as vision, reproduction, cell differentiation, and growth. The primary chemicals used in the study include β-carotene, ethyl (2E,4E/Z)-3-methylhexa-2,4-dienoate, and the Hoveyda II catalyst. The purpose of these chemicals is to undergo CM reactions, which are a type of olefin metathesis reaction that forms new carbon-carbon bonds under mild conditions, to produce retinoids like ethyl all-trans-retinoate. The study explores the regioselectivity and diastereoselectivity of these reactions, aiming to develop an effective and fast method for the preparation of retinoids for biological and structural studies.
10.1016/0040-4020(66)80130-8
The research aimed to investigate the relationship between the chemical structure and biological activity of vitamin A by synthesizing 9-, 13-, and 9,13-desmethyl homologues of vitamin A acetate. The study concluded that the presence of both methyl groups on the sidechain of the all-trans system is essential for growth-promoting properties, as the all-trans-13- and all-trans-9,13-desmethyl vitamin A acetates showed no activity, while the all-trans-9-desmethyl vitamin A acetate exhibited only about 4% of the activity compared to all-trans-vitamin A acetate. The synthesis involved chemicals such as truns-ionylidene acetaldehyde, truns-(2’,6’,6’-trimethylcyclohexen-1’-yl-1’)-pentadiene 2,4- dial, phosphonates of the appropriate crotonic acid esters, and reagents like lithium aluminum hydride (LAH) or diisobutylaluminum hydride (DIBAH) for reduction steps. Biological investigations were conducted to assess the growth-promoting properties of these synthesized compounds.
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