Xuegui Liu

Triterpenes from the fruits of Rosa laevigata with acetylcholinesterase and Aβ-aggregation inhibitory activities

A lupane-type triterpene (1) featuring a rare 2-hemiacetal moiety in its A ring and aromatic ester derivatives (2–6) were isolated from the fruits of R. laevigata and evaluated to possess acetylcholinesterase and Aβ-aggregation inhibitory activities. Their structures were determined by multi-spectroscopic methods, chemosynthesis and CD analysis.

Antioxidant properties of compounds isolated from wood vinegar by activity-guided and pH-gradient extraction

The chemical profile of wood vinegar (WV) was studied by gas chromatography-mass spectrometry (GC/MS), and 48 organic compounds were identified, including phenols which accounted for 2.0%. Antioxidant compounds were isolated from WV by an activity-guided isolation method for further investigation. The dichloromethane extract from WV exhibited the highest total phenolic content and demonstrated more potent antioxidant activity than the other extracts. Then, the phenols were enriched by pH gradient extraction method from the dichloromethane extract. Seven phenols were isolated from the WV using a sequence of column chromatographic purification steps over silica gel and C18 column, followed by semi-preparative HPLC and their structures were identified by 1H NMR and 13C NMR spectra. All the compounds showed potent antioxidant activities in the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline- 6-sulphonic acid (ABTS), and ferric-reducing antioxidant power (FRAP) assays. This study demonstrates that phenols isolated from WV have the potential to be used as antioxidant agents.