1H NMR-based metabolomics combined with HPLC-PDA-MS-SPE-NMR for investigation of standardized Ginkgo biloba preparations

Commercial preparations of Ginkgo biloba are very complex mixtures prepared from raw leaf extracts by a series of extraction and prepurification steps. The pharmacological activity is attributed to a number of flavonoid glycosides and unique terpene trilactones (TTLs), with largely uncharacterized pharmacological profiles on targets involved in neurological disorders. It is therefore important to complement existing targeted analytical methods for analysis of Ginkgo biloba preparations with alternative technology platforms for their comprehensive and global characterization. In this work, 1H NMR-based metabolomics and hyphenation of high-performance liquid chromatography, photo-diode array detection, mass spectrometry, solid-phase extraction, and nuclear magnetic resonance spectroscopy (HPLC-PDA-MS-SPE-NMR) were used for investigation of 16 commercially available preparations of Ginkgo biloba. The standardized extracts originated from Denmark, Italy, Sweden, and United Kingdom, and the results show that 1H NMR spectra allow simultaneous assessment of the content as well as identity of flavonoid glycosides and TTLs based on a very simple sample-preparation procedure consisting of extraction, evaporation and reconstitution in acetone-d6. Unexpected or unwanted extract constituents were also easily identified in the 1H NMR spectra, which contrasts traditional methods that depend on UV absorption or MS ionizability and usually require availability of reference standards. Automated integration of 1H NMR spectral segments (buckets or bins of 0.02 ppm width) provides relative distribution plots of TTLs based on their H-12 resonances. The present study shows that 1H NMR-based metabolomics is an attractive method for non-selective and comprehensive analysis of Ginkgo extracts

Alkaloids from the stem bark of an Australian population of Zanthoxylum ovalifolium

The aerial parts of Zanthoxylum ovalifolium (Rutaceae) have yielded the two novel benzo[c]phenanthridine alkaloids terihanine (8-demethylnitidine) and isoterihanine (9-demethylnitidine) together with nitidine, the unusual furoquinoline 5-methoxydictamnine, canthin-6-one and several common furocoumarins. The finding of benzo[c]phenanthridine and furoquinoline alkaloids in Australian material of this species confirms its chemical homogeneity throughout its range from India to Australia

Nonlinear optical properties of C-60 with explicit time-dependent electron dynamics

An explicit electron dynamics approach has been used to calculate the nonlinear optical properties of C-60 and its radical anion. An external perturbation, in the form of an oscillating electric field, induces the time-evolution of the molecular wavefunction. The time-averaged instantaneous dipole moment of the systems gives the molecular response to perturbations of varying field intensities and frequency of oscillation. The polarizabilities and the second-order hyperpolarizabilties have been calculated and are in good qualitative agreement with experimentally available data. In line with previous theoretical and experimental studies, the nonlinear effect is enhanced for the radical species

Have lichenized fungi delivered promising anticancer small molecules?

This review, covering the literature from 1844 to present (end 2017), probes questions concerning small molecule metabolites derived from lichens (lichenized fungi) and their impact in terms of providing compounds with significant promise in oncology. The review gives an overview of lichenized fungi and summarizes the classes of compounds obtained as metabolites from these organisms. A definition of what characteristics an actual “promising” anticancer compound should possess is also delineated. The review reports a brief overview on human cancer and then goes into depth in listing compounds with so-called “anticancer properties” that have been isolated from lichenized fungi, according to their small molecule structural classes. Five “most promising” compounds are discussed in-depth, also considering the possibility of obtaining sufficient amounts for further investigations