Molecular Networking Reveals Serpentinine-Related Bisindole Alkaloids from Picralima nitida, a Previously Well-Investigated Species.

Five new monoterpene indole alkaloids (1-5), including four serpentinine-related bisindoles and one alstonine derivative monomer, have been isolated from the aerial parts of Picralima nitida. Their structures were elucidated by analysis of their HRMS and NMR spectroscopic data, and their absolute configurations were deduced from the comparison of experimental and simulated ECD spectra. In addition, two known compounds (6 and 7), previously undescribed from P. nitida, have also been purified. The compound isolation workflow was guided by a molecular networking-based dereplication strategy. Twenty-three compounds were dereplicated from the EtOH extract of P. nitida and fractions network and were assigned various levels of identification confidence. The antiparasitic activities against Plasmodium falciparum as well as the cytotoxic activity against the MRC-5 cell line were determined for compounds 1-7.

3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 2: Basal Forebrain.

BACKGROUND AND PURPOSE: The basal forebrain contains multiple structures of great interest to emerging functional neurosurgery applications, yet many neuroradiologists are unfamiliar with this neuroanatomy because it is not resolved with current clinical MR imaging. MATERIALS AND METHODS: We applied an optimized TSE T2 sequence to washed whole postmortem brain samples (n = 13) to demonstrate and characterize the detailed anatomy of the basal forebrain using a clinical 3T MR imaging scanner. We measured the size of selected internal myelinated pathways and measured subthalamic nucleus size, oblique orientation, and position relative to the intercommissural point. RESULTS: We identified most basal ganglia and diencephalon structures using serial axial, coronal, and sagittal planes relative to the intercommissural plane. Specific oblique image orientations demonstrated the positions and anatomic relationships for selected structures of interest to functional neurosurgery. We observed only 0.2- to 0.3-mm right-left differences in the anteroposterior and superoinferior length of the subthalamic nucleus (P = .084 and .047, respectively). Individual variability for the subthalamic nucleus was greatest for angulation within the sagittal plane (range, 15°-37°), transverse dimension (range, 2-6.7 mm), and most inferior border (range, 4-7 mm below the intercommissural plane). CONCLUSIONS: Direct identification of basal forebrain structures in multiple planes using the TSE T2 sequence makes this challenging neuroanatomy more accessible to practicing neuroradiologists. This protocol can be used to better define individual variations relevant to functional neurosurgical targeting and validate/complement advanced MR imaging methods being developed for direct visualization of these structures in living patients.

3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 1: Brain Stem.

BACKGROUND AND PURPOSE: The brain stem is compactly organized with life-sustaining sensorimotor and autonomic structures that can be affected by numerous pathologies but can be difficult to resolve on conventional MR imaging. MATERIALS AND METHODS: We applied an optimized TSE T2 sequence to washed postmortem brain samples to reveal exquisite and reproducible brain stem anatomic MR imaging contrast comparable with histologic atlases. This resource-efficient approach can be performed across multiple whole-brain samples with relatively short acquisition times (2 hours per imaging plane) using clinical 3T MR imaging systems. RESULTS: We identified most brain stem structures at 7 canonical axial levels. Multiplanar or oblique planes illustrate the 3D course and spatial relationships of major brain stem white matter pathways. Measurements of the relative position, course, and cross-sectional area of these pathways across multiple samples allow estimation of pathway location in other samples or clinical subjects. Possible structure-function asymmetries in these pathways will require further study-that is, the cross-sectional area of the left corticospinal tract in the midpons appeared 20% larger (n = 13 brains, P < .10). CONCLUSIONS: Compared with traditional atlases, multiplanar MR imaging contrast has advantages for learning and retaining brain stem anatomy for clinicians and trainees. Direct TSE MR imaging sequence discrimination of brain stem anatomy can help validate other MR imaging contrasts, such as diffusion tractography, or serve as a structural template for extracting quantitative MR imaging data in future postmortem investigations.

Bioactive phloroglucinols from Mallotus oppositifolius.

The two new acylphloroglucinol derivatives, methylene-bis-aspidinol AB (1) and mallopposinol (2), together with the nine known compounds, aspidinol B (3), methylene-bis-aspidinol (4), (+)-α-tocopherol (5), lupeol (6), stigmasterol (7), phytol (8), bergenin (9), squalene (11) and methyl gallate (10) were isolated from the leaves of Mallotus oppositifolius. Their structures were elucidated by spectral analysis including MS, 1D and 2D-NMR spectroscopy. In vitro trypanocidal and antileishmanial activities of compounds 1-9 were evaluated. Mallopposinol (2) and aspidinol B (3) displayed weak antileishmanial activities against Leishmania donovani promastigotes, with EC50 values of 21.3 and 38.8µM, respectively. Only the methylene-bis-aspidinol (4) exhibited trypanocidal activity against Trypanosoma brucei brucei trypomastigotes (LC100=0.8µM) similar to the reference drug pentamidine (LC100=0.4µM).