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

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.

Development of a pH-dependent homogeneous liquid-liquid extraction by cold-induced phase separation in acetonitrile/water mixtures for determination of quinolone residues in animal-derived foods.

A simple extraction procedure coupled with liquid chromatography-Q Orbitrap high resolution mass spectrometry (LC-Q Orbitrap HRMS) for the determination of 19 quinolones in animal-derived foods (pork, fish, egg and milk) has been developed. Sample preparation is based on homogeneous liquid-liquid extraction at pH > 9 using water-miscible acetonitrile with cold-induced phase separation. The procedure allowed one-step enrichment and cleanup of all the 19 quinolones with different logP properties to lower aqueous phase, which eliminated the process of preconcentration and re-dissolution for sample solution. Furthermore, an adsorption phenomenon was observed between conventional borosilicate glass injection vials and most of quinolones. In detection analysis, a scheduled variable full scan strategy was performed to improve detection performance in Q Orbitrap HRMS. Under optimal conditions, a superior limit of quantitation (0.028-0.192 µg/kg) in animal-derived foods was achieved using this proposed method. Lastly, this method was validated and applied successfully in real samples.

Hydroazulene Diterpenes from a Dictyota Brown Alga and Their Antioxidant and Neuroprotective Effects Against Cerebral Ischemia-Reperfusion Injury.

Five new diterpenes, including four new hydroazulenes, (8R,11R)-8,11-diacetoxypachydictyol A (1), (8R*,11R*)-6-O-acetyl-8-acetoxy-11-hydroxypachydictyol A (2), (8R*,11S*)-8-acetoxy-11-hydroxypachydictyol A (3), and (8R*,11S*)-6-O-acetyl-8,11-dihydroxypachydictyol A (4), and a secohydroazulene derivative, named 7Z-7,8-seco-7,11-didehydro-8- acetoxypachydictyol A (5), were isolated from a South China Sea collection of a Dictyota sp. nov. brown alga, together with five known analogues (6-10). Structure elucidation was achieved by extensive spectroscopic analysis and comparison with reported data. All compounds showed potent antioxidant effects against H2O2-induced oxidative damage in neuron-like PC12 cells at a low concentration of 2 µM. The antioxidant property of dictyol C (9) was associated with activation of the Nrf2/ARE signaling pathway; it also showed neuroprotective effects against cerebral ischemia-reperfusion injury (CIRI) in a rat model of transient middle cerebral artery occlusion. As such, hydroazulene diterpenes could serve as lead structures for the development of novel neuroprotective agents against CIRI.