Rapid recognition and targeted isolation of potential anti-breast cancer xanthones in Hypericum bellum Li by "seed" mass spectra-based molecular networking and in silico MS/MS fragmentation.

INSTRUCTION: Hypericum bellum Li is rich in xanthones with various bioactivities, especially in anti-breast cancer. While the scarcity of mass spectral data of xanthones in Global Natural Products Social Molecular Networking (GNPS) libraries have challenged the rapid recognition of xanthones with similar structures. OBJECTIVE: This study is aimed to enhance the molecular networking (MN)-based dereplication and visualisation ability of potential anti-breast cancer xanthones from H. bellum to overcome the scarcity of xanthones mass spectral data in GNPS libraries. Separating and purifying the MN-screening bioactive xanthones to verify the practicality and accuracy of this rapid recognition strategy. METHODOLOGY: A combined strategy of "seed" mass spectra-based MN, in silico annotation tools, substructure identification tools, reverse molecular docking, ADMET screening, molecular dynamics (MDs) simulation experiments, and an MN-oriented separation procedure was first introduced to facilitate the rapid recognition and targeted isolation of potential anti-breast cancer xanthones in H. bellum. RESULTS: A total of 41 xanthones could only be tentatively identified. Among them, eight xanthones were screened to have potential anti-breast cancer activities, and six xanthones that were initially reported in H. bellum were obtained and verified to have good binding abilities with their paired targets. CONCLUSION: This is a successful case study that validated the application of "seed" mass spectral data could overcome the drawbacks of GNPS libraries with limited mass spectra and enhance the accuracy and visualisation of natural products (NPs) dereplication, and this rapid recognition and targeted isolation strategy can be also applicable for other types of NPs.

[Simultaneous determination of monosaccharides and oligosaccharides in Lycium barbarum L. by high performance liquid chromatography].

OBJECTIVE: To develop a rapid approach of refractive index detection with high performance liquid chromatography (HPLC) for the determination of rhamnose, fructose, glucose, surose and maltose in Lycium barbarum L. METHODS: The sample was extracted with water and the analyte was separated by Zorbax Carbohydrate column with acetonitrile-water as mobile phase. RESULTS: Good linear correlations between the concentrations and the peak areas of the analyte were found, with the correlation coefficients ranging from 0.9976 to 0.9998. The spiked recovery rates ranged from 92.27% to 101.93%, with 1.85%-3.27% of relative standard deviations (n=5). The limits of detection (S/N =3) were 4-6 mg/kg. CONCLUSION: The proposed method is suitable for the determination of monosaccharide and oligosaccharide in Lycium barbarum L.

[Determination of 4-nonylphenol and bisphenol A in rat serum by high performance liquid chromatography with fluorescence detection].

OBJECTIVE: This study was directed to the development of a simple and highly sensitive method for determination of 4-nonylphenol (4-NP) and bisphenol A (BPA) in rat serum using HPLC with fluorescence detector. METHODS: 4-NP and BPA in serum samples were extracted by a mixed solvent of n-hexane and diethyl ether (70:30), the organic layer was dried with nitrogen flow and dissolved with mobile phase. The operating conditions such as C18 column (250 mm x 4.6 mm, 5 microns), acetonitrile-ammonium acetate buffer (pH 4.5) as mobile phase at a flow rate of 1 ml/min and fluorescence detector with the excitation and emission wavelength at 227 nm and 313 nm respectively were used for the determination. RESULTS: There was good linear relationship between the concentrations of the analytes in rat serum and their peak areas in the ranges of 0.013-5.0 micrograms/ml for 4-NP and 0.004-3.0 micrograms/ml for BPA. The detection limit of the method was 13 ng/ml for 4-NP and 4 ng/ml for BPA. Recoveries of rat serum samples were 83.8%-100.0% for 4-NP and 83.3%-100.0% for BPA. The intra-day precision was 1.70%-2.70%, the inter-day precision was 2.06%-9.78%. CONCLUSION: The results showed that the method is suitable for the determination of BPA and 4-NP in serum.