Publications by authors named "Naoko Yasobu"
Recently, quantitative NMR (qNMR), especially H-qNMR, has been widely used to determine the absolute quantitative value of organic molecules. We previously reported an optimal and reproducible sample preparation method for H-qNMR. In the present study, we focused on a P-qNMR absolute determination method.
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- Quantitative NMR (qNMR) is used to establish the absolute quantitative value of standards for HPLC-based quantification, specifically for hygroscopic substances like saikosaponin a and indocyanine green (ICG).
- The study highlights the impact of humidity on the purity determination of ICG, noting that non-controlled humidity resulted in higher variation (86.12 ± 2.70%) and residual ethanol in the samples.
- Using a controlled humidity environment, the purity of ICG decreased variability (84.19 ± 0.47%), and employing a constant temperature and humidity box minimized variation further (82.26 ± 0.19%), suggesting its use for standard reference preparation in JP
Novel colchicine derivatives possessing various substituents at the C4 position were prepared. Among them, 4-halo derivatives 3-6 were found to exhibit higher activity against cancer cell lines (A549, HT29, HCT116) as well as on mice transplanted with the HCT116 human colorectal carcinoma cell line than colchicine (1). Further, utilizing the 4-substituted colchicines, we prepared pro-drugs having a dipeptide side chain and demonstrated that these pro-drugs were activated by cathepsin B, an enzyme overexpressed in tumor cells, and exhibited selective toxicity to the tumor cells.
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