Development of a novel method for analysing N-acetyl-DL-leucine enantiomers in human fingernail by UPLC-ESI-MS/MS and the evaluation in diabetes mellitus.

BACKGROUND: Recent research has been reported that N-acetyl-leucine content is significantly reduced in the saliva of diabetic patients, but no reports of detection in human nails have been found. This study aims to develop a novel method for the chiral separation of N-acetyl-DL-leucine (Ac-DL-Leu) in human fingernails to investigate the differences between healthy volunteers (HVs), prediabetes (PDs) and diabetic patients (DPs), and to verify its effectiveness in early warning of diabetes. METHOD: Chiral resolution was performed using DBD-Apy pre-column derivatization on a C18 column (2.1 × 150 mm, 1.9 µm) at 40 °C, and detected by UPLC-ESI-MS/MS. RESULTS: The resolution and the limit of detection (LOD) of Ac-DL-Leu were 1.75 and 1.50 fmol, respectively. The linear range of Ac-DL-Leu was 10-2000 fmol and the determination coefficient (R2) was above 0.9997. The recovery of Ac-DL-Leu in human nails was 96.92-105.69 %. The contents of Ac-D-Leu and Ac-L-Leu were analyzed in 18 HVs, 13 PDs and 16 DPs fingernails. The results showed that their contents were significantly lower in DPs than in PDs and HVs (p < 0.0001). CONCLUSIONS: A method for evaluating the effectiveness of Ac-DL-Leu enantiomers in human fingernails as a biomarker for diabetes was firstly developed.

Comprehensive characterization of the chemical composition of Lurong dabu decoction and its absorbed prototypes and metabolites in rat plasma using UHPLC-Q Exactive Orbitrap-HRMS.

Lurong Dabu decoction (LRDBD) is an effective traditional Chinese Korean ethnic medicine prescription composed of eight herbs, which is used for treating asthma. However, its material basis has not been studied yet. Herein, the use of a new and highly sensitive UHPLC-Q Exactive Orbitrap-HRMS technique is proposed for the high-resolution and accurate identification of the material basis of LRDBD. We identified 122 compounds belonging to different groups in LRDBD. Among these, 23 ingredients produced by decoction were identified and compared with 8 single herb compounds. Moreover, 39 other significantly different compounds were identified. Additionally, 29 absorbed prototype components and 35 metabolites were identified in rat plasma. Half of the prototype components were originated from antler velvet, it has corroborated the compatibility theory of Sasang medicine. To the best of our knowledge, the material basis of LRDBD was characterized for the first time. Our findings provide basic data and a method for further discovering potential drug targets and revealing the action mechanism of LRDBD in asthma treatment.

[Development of a highly sensitive separation method for the analysis of metabolites in human nails and applications in the diagnosis of chronic disease].

We have recently developed target-specific derivatization methods for determining the metabolites in human nails. The nails can be used to obtain physiologic information and may serve as noninvasive biosamples for the diagnosis of chronic disease. Certain endogenous biogenic D,L-amino acids, polyamines, and advanced glycation end-products (AGEs) have been detected in human nails. By identifying biological trace components in human samples, we tested the possibility of using these new methods to diagnose chronic disease, i.e., diabetes and lung cancer. When comparing the index from diabetic patients to that from healthy volunteers, there was no significant difference in the content of L-amino acids, methylglyoxal, and glyoxal in the nails. However, a statistically significant correlation was observed between the D/L-amino acid concentration ratios (Ala, Val, Ile, Leu; p<0.01), and 3-deoxyglucosone concentrations (p<0.001). Additionally, in the lung cancer patient group, as compared with healthy volunteers, the concentrations of spermine showed a statistically significant (p<0.05) correlation. This review describes our current target-specific derivatization UPLC-ESI-MS methods for the determination of metabolites and related compounds, e.g., D,L-amino acids, polyamines, and AGEs, in human nails. Advanced applications of human nails as new, noninvasively obtained biosamples for the diagnosis of chronic disease are also described.