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Four Undescribed Chromane-Type Meroterpenoids From Sargassum siliquastrum and Their Inhibitory Activity Against
Mafumi Horiuchi1, Joh Yamanaka2, Hideyuki Shigemori3,4
1Graduate School of Bioresources and Environmental Science, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan.
Chemistry & Biodiversity
|July 28, 2026
Summary
Four new meroterpenoids from the brown alga Sargassum siliquastrum, sargasilides H-K, were identified. Sargasilide J demonstrated significant inhibition of amyloid-beta42 aggregation and delayed paralysis in C. elegans.
Area of Science:
- Marine Natural Products Chemistry
- Neurodegenerative Disease Research
- Algal Biochemistry
Background:
- Brown algae, such as Sargassum siliquastrum, are rich sources of diverse bioactive compounds.
- Amyloid-beta42 (Aβ42) aggregation is a key pathological hallmark of Alzheimer's disease.
- Meroterpenoids represent a class of complex natural products with varied biological activities.
Purpose of the Study:
- To isolate and characterize novel meroterpenoids from Sargassum siliquastrum.
- To evaluate the potential of these compounds in inhibiting Aβ42 aggregation.
- To investigate the in vivo efficacy of active compounds in a C. elegans model.
Main Methods:
- Isolation and purification of compounds using chromatographic techniques.
- Structural elucidation via comprehensive spectroscopic analyses (NMR, MS).
- Determination of absolute configurations using electronic circular dichroism and modified Mosher's method.
- In vitro assessment of Aβ42 aggregation inhibition using thioflavin T fluorescence assay.
- In vivo evaluation in a transgenic Caenorhabditis elegans model.
Main Results:
- Four new chromane-type meroterpenoids, sargasilides H-K (1-4), were successfully isolated and characterized.
- Sargasilide J (3) exhibited potent inhibitory activity against Aβ42 aggregation in vitro.
- Compound 3 significantly delayed paralysis in a C. elegans model, indicating in vivo efficacy.
Conclusions:
- Sargassum siliquastrum is a valuable source of structurally unique meroterpenoids.
- Sargasilide J shows promise as a potential therapeutic agent for targeting Aβ42-related pathologies.
- These findings contribute to understanding the structure-activity relationships of chromane-type meroterpenoids in amyloid aggregation inhibition.
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