Dual Beam Depth Profiling and Imaging with Argon and Bismuth Clusters of Prenylated Stilbenes on Glandular Trichomes of Macaranga vedeliana

Structure-Based Design of a Lead Compound Derived from Natural Schweinfurthins with Antitumor Properties That Target Oxysterol-Binding Protein

Schweinfurthins (SWs) are naturally occurring prenylated stilbenes with promising anticancer properties. They act through a novel mechanism of action similar to that of other families of natural compounds. Their known target, oxysterol-binding protein (OSBP), plays a crucial role in controlling the intracellular distribution of cholesterol. We synthesized 15 analogues of SWs and demonstrated for the first time that their cytotoxicity as well as that of natural derivatives correlates with their affinity for OSBP. Through this extensive SAR study, we selected one synthetic analogue obtained in one step from SW-G. Using its fluorescence properties, we showed that this compound recapitulates the effect of natural SW-G in cells and confirmed that it leads to cell death via the same mechanism. Finally, after pilot PK experiments, we provided the first evidence of its in vivo efficacy in combination with temozolomide in a patient-derived glioblastoma xenograft model.

Time-of-flight secondary ion mass spectrometry imaging in cultural heritage: A focus on old paintings

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging is a surface analysis technique that identifies and spatially resolves the chemical composition of a sample with a lateral resolution of less than 1 μm. Depth analyses can also be performed over thicknesses of several microns. In the case of a painting cross section, for example, TOF-SIMS can identify the organic composition, by detecting molecular ions and fragments of binders, as well as the mineral composition of most of the pigments. Importantly, the technique is almost not destructive and is therefore increasingly used in cultural heritage research such as the analysis of painting samples, especially old paintings. In this review, state of the art of TOF-SIMS analysis methods will be described with a particular focus on tuning the instruments for the analysis of painting cross sections and with several examples from the literature showing the added value of this technique when studying cultural heritage samples.

Cytotoxic Phenolic Compounds from Fruit Glandular Trichomes of Macaranga tanarius

A new flavonoid, macatanarin D (1), together with five known stilbenes (2-6), was isolated from fruit glandular trichomes of Macaranga tanarius. Their structures were elucidated on the basis of spectroscopic methods and through comparison with data reported in the literature. All isolated compounds were evaluated for their cytotoxic activities against KB and MCF-7 cell lines. Compounds 3, 4, and 5 showed the strongest activities against both cell lines with IC₅₀ values in the range of 0.03-0.12 μM, and compound 2 only showed a significant cytotoxicity against KB cell line (IC₅₀ = 0.26 μM) and a moderate cytotoxicity against MCF-7 (IC₅₀ = 10.4 μM). Compounds 1 and 6 showed weak cytotoxic activities against KB cell line with IC₅₀ values of 29.3 and 24.7 μM, respectively.

Non-volatile natural products in plant glandular trichomes: chemistry, biological activities and biosynthesis

The investigation methods, chemistry, bioactivities, and biosynthesis of non-volatile natural products involving 489 compounds in plant glandular trichomes are reviewed.

Molecular Colocalization Using Massive Gold Cluster Secondary Ion Mass Spectrometry

We report on the ion emission from impacts of hypervelocity massive gold clusters for use in secondary ion mass spectrometry. Two massive gold clusters are considered, 520 keV Au₄₀₀⁴⁺ and 1040 keV Au₂₈₀₀⁸⁺. The emission of fragment ions and molecular ions is evaluated for a series of neat samples, glycine, phenylalanine, arginine, and gramicidin S. A 2 to 4-fold increase of molecular ion emission is observed from impacts of 1040 keV Au₂₈₀₀⁸⁺ versus 520 keV Au₄₀₀⁴⁺. Compared to impacts of 20 keV Ar₂₀₀₀⁺ and 20 keV (H₂O)₇₀₀₀⁺ in static conditions, impacts of 1040 keV Au₂₈₀₀⁸⁺ display a 6 to 9-fold increase in the number of detected molecular ions per projectile impact. To explain the increased emission of molecular species, we examine the size of the impact craters and calculate the ratio of molecular ions to fragment ions. The characterization of Au₂₈₀₀⁸⁺ and the operating conditions of the gold liquid metal ion source are presented.

Gas Cluster Ion Beams for Secondary Ion Mass Spectrometry

Gas cluster ion beams (GCIBs) provide new opportunities for bioimaging and molecular depth profiling with secondary ion mass spectrometry (SIMS). These beams, consisting of clusters containing thousands of particles, initiate desorption of target molecules with high yield and minimal fragmentation. This review emphasizes the unique opportunities for implementing these sources, especially for bioimaging applications. Theoretical aspects of the cluster ion/solid interaction are developed to maximize conditions for successful mass spectrometry. In addition, the history of how GCIBs have become practical laboratory tools is reviewed. Special emphasis is placed on the versatility of these sources, as size, kinetic energy, and chemical composition can be varied easily to maximize lateral resolution, hopefully to less than 1 micron, and to maximize ionization efficiency. Recent examples of bioimaging applications are also presented.