New iboga-type alkaloids from Ervatamia officinalis and their anti-inflammatory activity

Dehydroervatamine as a promising novel TREM2 agonist, attenuates neuroinflammation

Microglia play a dual role in neuroinflammatory disorders that affect millions of people worldwide. These specialized cells are responsible for the critical clearance of debris and toxic proteins through endocytosis. However, activated microglia can secrete pro-inflammatory mediators, potentially exacerbating neuroinflammation and harming adjacent neurons. TREM2, a cell surface receptor expressed by microglia, is implicated in the modulation of neuroinflammatory responses. In this study, we investigated if and how Dehydroervatamine (DHE), a natural alkaloid, reduced the inflammatory phenotype of microglia and suppressed neuroinflammation. Our findings revealed that DHE was directly bound to and activated TREM2. Moreover, DHE effectively suppressed the production of pro-inflammatory cytokines, restored mitochondrial function, and inhibited NLRP3 inflammasome activation via activating the TREM2/DAP12 signaling pathway in LPS-stimulated BV2 microglial cells. Notably, silencing TREM2 abolished the suppression effect of DHE on the neuroinflammatory response, mitochondrial dysfunction, and NF-κB/NLRP3 pathways in vitro. Additionally, DHE pretreatment exhibited remarkable neuroprotective effects, as evidenced by increased neuronal viability and reduced apoptotic cell numbers in SH-SY5Y neuroblastoma cells co-cultured with LPS-stimulated BV2 microglia. Furthermore, in our zebrafish model, DHE pretreatment effectively alleviated behavioral impairments, reduced neutrophil aggregation, and suppressed neuroinflammation in the brain by regulating TREM2/NF-κB/NLRP3 pathways after intraventricular LPS injection. These findings provide novel insights into the potent protective effects of DHE as a promising novel TREM2 agonist against LPS-induced neuroinflammation, revealing its potential therapeutic role in the treatment of central nervous system diseases associated with neuroinflammation.

Monoterpenoid indole alkaloids from the stems and leaves of Tabernaemontana bovina and their potential antiproliferative activities

A phytochemical study on the stems and leaves of Tabernaemontana bovina led to the isolation and identification of a new monoterpenoid indole alkaloid, taberboviline (1), together with seven known monoterpenoid indole alkaloids (2-8). The chemical structure of 1 was elucidated on the basis of extensive spectral data analyses and the known compounds were identified by comparing their experimental spectral data with the reported data in the literature. All isolated indole alkaloids were evaluated for their antiproliferative activities against five human cancer cell lines in vitro. Monoterpenoid indole alkaloids 1-8 exhibited notable antiproliferative activities against five human cancer cell lines with IC50 values ranging from 0.58 ± 0.05 to 26.19 ± 0.16 μM.

Case report: Significant lesion reduction and neural structural changes following ibogaine treatments for multiple sclerosis

Multiple sclerosis (MS) is a debilitating neurodegenerative disease characterized by demyelination and neuronal loss. Traditional therapies often fail to halt disease progression or reverse neurological deficits. Ibogaine, a psychoactive alkaloid, has been proposed as a potential neuroregenerative agent due to its multifaceted pharmacological profile. We present two case studies of MS patients who underwent a novel ibogaine treatment, highlighting significant neuroimaging changes and clinical improvements. Patient A demonstrated substantial lesion shrinkage and decreased Apparent Diffusion Coefficient (ADC) values, suggesting remyelination and reduced inflammation. Both patients exhibited cortical and subcortical alterations, particularly in regions associated with pain and emotional processing. These findings suggest that ibogaine may promote neuroplasticity and modulate neurocircuitry involved in MS pathology.

Total Synthesis of Ervaoffine J and K

Herein, we describe the total synthesis of ervaoffine J & K from a central intermediate. Ervaoffine J was synthesized in eight steps in 14 % yield. Our strategy features an aerobic Winterfeldt oxidation to introduce the 4-quinolone moiety. Ervaoffine K was produced in ten steps and 10 % yield. The synthesis leveraged (bromodifluoromethyl)-trimethylsilane to induce a regioselective von Braun-type C-N bond fragmentation. This C-N bond cleavage unveiled the tetrasubstituted all-syn cyclohexane core of ervaoffine K and enabled the completion of its synthesis.

Monoterpenoid indole alkaloid adducts and dimers from Melodinus fusiformis

Eight unprecedented monoterpenoid indole alkaloid (MIA) adducts and dimers, melofusinines A-H (1-8), and three undescribed melodinus-type MIA monomers, melofusinines I-K (9-11), together with six putative biogenetic precursors were isolated from the twigs and leaves of Melodinus fusiformis Champ. ex Benth. Compounds 1 and 2 are unusual hybrid indole alkaloids incorporating an aspidospermatan-type MIA with a monoterpenoid alkaloid unit via C-C coupling. Compounds 3-8 feature the first MIA dimers constructed through an aspidospermatan-type monomer and a rearranged melodinus-type monomer with two different types of couplings. Their structures were elucidated by spectroscopic data, single crystal X-ray diffraction, and calculated electric circular dichroism spectra analysis. In addition, dimers 5 and 8 showed significant neuroprotection effects on MPP ⁺-injured primary cortical neurons.

Two new aspidosperma-type monoterpenoid indole alkaloids from Ervatamia officinalis

Two new aspidosperma-type monoterpenoid indole alkaloids, 16-O-methylvoafinine (1) and 14,15-diepi-voafinidine (2) were isolated from the aerial parts of Ervatamia officinalis. Their structures were established by comprehensive spectroscopic analysis including 1D and 2D NMR, HR-ESI-MS, and electronic circular dichroism calculation. The isolated compounds were evaluated for cytotoxic activities against HepG2, MCF-7, and A549 cell lines by CCK-8 assay.