The objective of this study was to investigate the structure characteristics of flavonoids that act as inhibitors for heterocyclic aromatic amines (HAAs) formation. Five quantitative structure–activity relationship models for predicting the inhibitory rates of HAAs (norharman, harman, PhIP, MeIQx, and 4,8‐DiMeIQx) were established using selected chemometric parameters (R2: 0.591–0.920), and indicated that the hydrophobicity, hydroxyl groups, and topological structure of flavonoids played important roles in the inhibition of HAAs formation. The 5,7‐dihydroxyls in meta‐position of the A‐ring and the 4′‐hydroxyl in the B‐ring of flavonoids were critical for the inhibitory effects of HAAs, whereas the introduction of 3‐hydroxyl and 3‐O‐glucoside in the C‐ring reduced the inhibitory effects. Catechin served as the most effective inhibitor of HAAs followed by luteolin and genistein. The study can bring us a broader idea for controlling the formation of HAAs according to the structure of flavonoids. Practical applications Heterocyclic aromatic amines (HAAs) are a class of organic substances with carcinogenic and mutagenic effect formed during the heating process of meat products. The formation of HAAs can be inhibited by adding natural antioxidants such as flavonoids to the meat during pretreatment. This inhibition is influenced by the unique structure of flavonoids. Thus, there has been an increasing demand to exploit the effective HAAs inhibitors from flavonoids by structure characteristics. Our study showed that the inhibitory effect of flavonoids on the formation of HAAs was mainly depended on their hydrophobicity, hydroxyl groups, and topological structure using the multiple QSAR models. Thus, effective HAAs inhibitors can be explored from dietary flavonoids according their structure characteristics.

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Effective cysteine (Cys) detection is extremely important for early disease monitoring and diagnosis. In this study, a fluorescent probe (PHO) comprising 1,10-phenanthroline carboxaldehyde as the ligand and cobalt as the central ion was synthesized to detect Cys. The synthesized PHO exhibited enhanced fluorescence at 603 nm in the presence of Cys in HEPES buffer. Furthermore, the probe detected Cys concentrations as low as 0.6 μmol/L, demonstrating high sensitivity. Additionally, a strong linear relationship was established between the Cys concentration and normalized intensity of fluorescence. Importantly, the high selectivity was retained even in the presence of other interfering compounds. Consequently, this method can serve as a novel approach for detecting Cys in physiological systems.

For the sensitive and specific detection of CAP in milk, a label-free fluorescence strategy was established based on guanine (G)-quadruplex/N-methyl mesoporphyrin IX (NMM) complex formation and hybridization chain reaction (HCR) amplification.