The present study aimed to systematically assess the potential biomarkers in the serum samples of patients with long-term inhalation of caffeine-sodium benzoate (CSB). LC-MS was applied to analyze the metabolic profiles of serum samples of patients with the long-term intake of CSB (n = 35) and other volunteers with no intake of CSB treated as the control group (n = 35). The raw data of metabolic profiles were analyzed via principal component analysis, partial least squares analysis, and orthogonal partial least squares analysis. MBRole 2.0 online tools were used to analyze the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of different metabolites. The serum metabolic profiles showed several metabolites with large variations, including 2-propyl-2,4-pentadienoic acid, 24-hydroxycholesterol, 3-O-sulfogalactosylceramide (d18:1/24:1(15Z)), 3-Osulfogalactosylceramide (d18:1/12:0), 3-O-sulfogalactosylceramide (d18:1/14:0), 3a,7a-dihydroxy-5b-cholestan-26-al, 3a,7a-dihydroxy-5b-cholestane, 7a,25-dihydroxycholesterol, bilirubin, and dehydroepiandrosterone sulfate. The Kyoto Encyclopedia of Genes and Genomes pathways involved in metabolism included 'choline metabolism in cancer' and 'glycerophospholipid metabolism'. In conclusion, the present study provides a basis with which to explore the molecular-specific mechanisms concerning the effects of the long-term inhalation of CSB on human physical and mental health.

The present study reports an innovative finding that alumina containing water or primary alcohol catalyzes the hydrolysis or alcoholysis, respectively, of the product formed through AlCl3‐mediated Friedel‐Crafts alkylation of methyl‐substituted benzenes and CHCl3. The former and later reactions mainly provided hydroxy‐ and alkoxy‐substituted diarylmethanes, respectively, while the reference reactions without alumina provided bisarylchloromethane. This method enables the selective syntheses of diphenylmethanol derivatives with very simple procedures, without expensive reagents and apparatuses. Furthermore, the alumina used in the reaction could be recycled by washing with water and subsequent drying. From the viewpoint of material recycling, this function is very important for the development of sustainable chemical reactions.