Styryllactones from Goniothalamus tamirensis

Alkaloids and Styryl lactones from Goniothalamus ridleyi King and Their α-Glucosidase Inhibitory Activity

Gonioridleylactam (1), a new compound, is a unique dimeric aristolactam isolated from the EtOAc extract of the twigs of Goniothalamus ridleyi King. The structure of gonioridleylactam (1) consists of two different aristolactams linked together with two methylenedioxy bridges at C-3/C-3' and C-4/C-4', generating a ten-membered ring of [1,3,6,8]tetraoxecine. A new natural product, gonioridleyindole (3-hydroxymethyl-1-methyl-1H-benz[f]indole-4,9-dione, 2), together with eight known compounds (3-10) were also isolated from this plant. Their structures were extensively characterized by spectroscopic methods and comparisons were made with the literature. Compounds 1-4, 7, and 9 were evaluated for their α-glucosidase inhibitory activity. Of these, 3,5-demethoxypiperolide (7) displayed the highest α-glucosidase inhibitory activity, with an IC₅₀ value of 1.25 µM.

Discovery of unreported ginkgolides of anti-PAF activity using characteristic ion and neutral loss recognition strategy in Ginkgo biloba L

Ginkgolides are the most important bioactive components of Ginkgo biloba L, of which ginkgolide B has been successfully developed and marketed as a drug. The reported ginkgolides are very rare and exhibit a complex matrix due to the chemodiversity of Ginkgo biloba L. Herein, the global profile of characteristic ion and neutral loss recognition strategy were used for to discover eight undescribed ginkgolides, very rare cyclohexane ginkgolides R-V, ginkgolides D-F, and eight known ginkgolides. These ginkgolides were target isolated and identified using high-resolution mass spectrometry, nuclear magnetic resonance spectroscopy, and X-ray crystallography. The undescribed and known ginkgolides exhibited antiplatelet aggregation activities. In particular, compounds U and D had IC₅₀ values of 2.20 ± 0.15 and 6.50 ± 0.87 μM, respectively. This study has enriched the known structural diversity of ginkgolides and extended the application of mass spectrometry to the global profiling of natural products present in Ginkgo biloba L. Moreover, it could help chemists rapidly discover unreported compounds from a complex matrix.

A styrylpyrone dimer isolated from Aniba heringeri causes apoptosis in MDA-MB-231 triple-negative breast cancer cells

The styrylpyrone dehydrogoniothalamin (1) and two of its dimers (2 and 3) were isolated from the leaves of Aniba heringeri (Lauraceae). Compound 3 is new, while 1 and 2 are being reported for the first time in this species. Structures were determined by 1D- and 2D-NMR spectroscopy, mass spectrometry, and optical rotation data. Cytotoxic effects and selectivity indices were evaluated in five neoplastic cell lines-PC-3 (prostate), 786-0 (renal), HT-29 (colon), MCF-7, and MDA-MB-231 (breast)-and a non-neoplastic cell line, (NIH/3T3, murine fibroblast). Compound 1 inhibited cell growth by 50% (GI₅₀) at concentrations in the 90.4-175.7 μM range, while 2 proved active against MCF-7 and MDA-MB-231 breast cells (GI₅₀ = 12.24, and 34.22 μM, respectively). Compound 3 showed strong cytotoxicity (GI₅₀ = 4.4 μM) against MDA-MB-231 (an established basal triple-negative breast carcinoma (TNBC) cell line), with a high selective index of 35. This compound was subsequently evaluated for apoptosis induction in MDA-MB-231 cells, using GI₅₀ and 50% lethal concentrations (LC₅₀). Flow cytometry analysis showed that at LC₅₀ compound 3 induced cell death with phosphatidylserine externalization and caspase-3 activation. Apoptotic genes were measured by RT-qPCR, revealing an upregulation of BAX, with an increase in expression of the BAX/BCL2 ratio in treated cells. Fluorescence microscopy disclosed morphological changes related to apoptosis. Overall, these findings showed compound 3 to be a promising prototype against TNBC cells that tend to respond poorly to conventional therapies.

Synthesis and crystal structure of (±)-Goniotamirenone C

The structure of the racemic version of the natural product Goniotamirenone C [racemic anti-6-(2-chloro-1-hy-droxy-2-phenyl-eth-yl)-2H-pyran-2-one, C13H11ClO3] at 150 K is reported. The compound crystallizes with monoclinic (P21/n) symmetry and with Z' = 2. One independent mol-ecule is ordered while the other independent mol-ecule exhibits an inter-esting whole-mol-ecule enanti-omeric disorder with occupancies of 0.846 (4) and 0.154 (4). The independent mol-ecules are hydrogen bonded with -OH⋯O=C linkages into chains that run parallel to the a axis. This structural analysis corrects our previous assignment as the syn isomer [Meesakul et al. (2020 ▸). Phytochemistry, 171, 112248-112255].