ABSTRACT
Vitamin D deficiency is associated with various diseases such as obesity, digestive problems, osteoporosis, depression, and infections, and has therefore emerged as a topic of great interest in public healthcare. The quantitative assessment of 25-hydroxyvitamin D (25-OH VD) in human serum may accurately reflect the nutritional status of vitamin D in the human body, which is significant for the prevention and treatment of vitamin D-deficient patients. In this study, we developed an assay for quantitative detection of 25-OH VD based on the 25-OH VD monoclonal antibody (mAb), and identified the optimal process parameters. The following process settings were found to be suitable for the test strips: pH of 7.6, 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) ratio of 1:2000, and the anti-25-OH VD mAb ratio was 1:8. The equilibration time of the immune dynamic assay was 15 min. Under optimal conditions, the quantum dot nanoparticle-based fluorescent immunochromatographic assay (QDs-FICA) exhibited dynamic linear detection of 25-OH VD in PBS, from 5 ng/mL to 100 ng/mL, and the strip quantitative curve could be represented by the following regression equation: y = -0.02088 logx)+1.444 (R2 = 0.9050). The IC50 of the QDs-FICA was 39.6 ± 1.33 ng/mL. The specificity of the QDs-FICA was evaluated by running several structurally related analogues, including 25-OH VD2, 25-OH VD3, 1,25-OH2VD3, 1,25-OH2VD2, VD2, and VD3. The coefficients of variation were all below 10%. The shelf life of the test strips in this study was about 160 days at room temperature. Briefly, this study is the first to perform QDs-FICA for the rapid visual and quantitative detection of 25-OH VD, with great potential significance for clinical diagnosis of vitamin D-associated diseases.
ABSTRACT
Three series of avermectin B2a oxime ester derivatives were synthesized using avermectin B2a as starting material. All of the compounds were characterized by 1H NMR, 13C NMR, and HRMS. Bioassay results indicated that some of the derivatives (8b, 8c, 8d, 8f, 11k, 11l, 14c, 14j) showed potent insecticidal activities against Myzus persicae, Caenorhabditis elegans, or Tetranychus cinnabarinus. As shown by initial insecticidal activity data, compound 8d showed excellent activities (>90%) against M. persicae and C. elegans, which were more potent than that of avermectin B2a. Compound 8d might be a lead compound for designing new avermectin B2a derivatives.
ABSTRACT
Based on the structural framework of a pyriproxyfen metabolite, nineteen oxime ester derivatives were synthesized via reaction of the carboxylic acids with 4-(2-(2-pyridinyloxy)ethoxy)benzaldehyde oxime. The corresponding structures were comprehensively characterized by ¹H-nuclear magnetic resonance (NMR), 13C-NMR, and electrospray ionization high-resolution mass spectrometry (ESI-HRMS). All of the compounds were screened for their insecticidal activities against Plutella xylostella and Myzus persicae, and for their ovicidal activities against Helicoverpa armigera eggs. The results obtained show that most of the oxime ester derivatives displayed moderate to high insecticidal activities and ovicidal activities at a concentration of 600 ug/mL. In particular, the ovicidal activity of compounds 5j, 5o, 5p, 5q, and 5s was determined to be 100%. Importantly, some of the compounds presented even higher biological activities than the reference compound pyriproxyfen. For example, compound 5j displayed an insecticidal activity value of 87.5% against Myzus persicae, whereas the activity value of pyriproxyfen was 68.3% at a concentration of 600 ug/mL. Among the synthesized compounds 5j and 5s exhibited broad biological activity spectra.
