Development of a colloidal gold strip assay for the detection of total homocysteine in serum samples.

Homocysteine (Hcy) is an amino acid found in the human body and has the potential to predict cardiovascular risk where timely detection and treatment are very important. In this study, we established a method to combine enzymatic hydrolysis with a colloidal gold lateral flow immunoassay (LFIA) for the detection of total Hcy (tHcy) based on the monoclonal antibody (mAb) 3B3 against S-adenosyl-L-homocysteine (SAH). The 50% inhibitory concentration (IC50) for this mAb against SAH was 2.94 nM with a linear range of 0.73-11.75 nM. The developed LFIA could detect SAH with a vLOD and cLOD of 10 nM and 2.07 nM, respectively. For tHcy detection in serum samples, the LFIA strip was able to detect tHcy after enzymatic hydrolysis, and the results correlated well with that of an enzymatic cycling test kit.

In Vitro Comparative Analysis of the Effect and Structure-Based Influencing Factors of Flavonols on Lipid Accumulation.

Flavonols represented by quercetin have been widely reported to have biological activities of regulating lipid metabolism. However, the differences in flavonols with different structures in lipid-lowering activity and the influencing factors remain unclear. In this study, the stability, transmembrane uptake ratio, and lipid metabolism regulation activities of 12 flavonol compounds in the 3T3-L1 cell model were systematically compared. The results showed that kaempferide had the highest cellular uptake ratio and the most potent inhibitory effect on adipogenesis at a dosing concentration of 20 µM, followed by isorhamnetin and kaempferol. They inhibited TG accumulation by more than 65% and downregulated the expression of PPARγ and SREBP1c by more than 60%. The other four aglycones, including quercetin, did not exhibit significant activity due to the structural instability in the cell culture medium. Meanwhile, five quercetin glucosides were quite stable but showed a low uptake ratio that no obvious activity was observed. Correlation analysis also showed that for 11 compounds except galangin, the activity was positively correlated with the cellular uptake ratio (p < 0.05, r = 0.6349). These findings may provide a valuable idea and insight for exploring the structure-based activity of flavonoids at the cellular level.