Anti-Neuroinflammatory Meroterpenoids from a Chinese Collection of the Brown Alga Sargassum siliquastrum

Abstract

Nine new chromane-type meroterpenoids, including the rare nor-meroterpenoid sargasilol A (1) and the eight meroditerpenoids sargasilols B–I (2–9), were isolated from a China Sea collection of the brown alga Sargassum siliquastrum, together with six known analogues (10–15). The structures of the new chromanes were identified by extensive spectroscopic analysis and by comparison with previously reported data. Compounds 1–3 and 6–15 exhibited inhibition against LPS-induced NO production in BV-2 microglial cells, and 1, with a shorter carbon chain, was the most active one. Compound 1 was established as an anti-neuroinflammatory agent through targeting the IKK/IκB/NF-κB signaling pathway. As such, the chromanes from brown algae could provide promising anti-neuroinflammatory lead compounds for further structural modification.

Isatin-based spiro indolenine alkaloids from Isatis indigotica Fortune with anti-neuroinflammatory and acetylcholinesterase inhibitory effects

“…20–23 The increased oxidative stress and decreased acetylcholine (ACh) were believed to be critical factors in the development of AD. 24–27 To establish the appropriate experimental concentration of the four compounds, a CCK-8 kit was adopted to detect the BV2 cell viability. The results showed that the four compounds at 3.125, 6.25, 12.5, 25, and 50 μM have no toxicity.…”

Neuroprotective effect of acetoxypachydiol against oxidative stress through activation of the Keap1-Nrf2/HO-1 pathway

“…Western-blot assay was established referred to previously reported protocols [ 20 ]. Briefly, PC12 Cells were seeded in 6-well plates at a density of 4 × 10 5 cells per well.…”

“…Cells were seeded on cell slides and placed in 24-well plates at a number of 1 × 10 5 cells per well and then processed as described [ 20 ]. After treatments with drugs, the cells were fixed with paraformaldehyde, blocked with goat serum, incubated with an anti-Nrf2 antibody overnight, and then with a secondary antibody for 1 h in the dark.…”

“…Studies have demonstrated that certain algal extracts exhibit promising neuroprotective activities [ 18 ], making them valuable for further exploration in the development of neuroprotectants. In recent years, our research has continued to explore the neuroprotective active ingredients in marine brown algae, identifying several diterpenes with antioxidant and neuroprotective effects [ 19 , 20 ]. The genus Dictyota (family Dictyotaceae) is an important source of medicinal algae, documented in the Chinese Marine Materia Medica for its use in detoxification and inflammation suppression.…”