Aromatic glycosides and lignans glycosides with their acetylcholinesterase inhibitory activities from the leaves of Picrasma quassioides.

In this study, eight new natural products were isolated from the leaves of Picrasma quassioides. Spectroscopic techniques were used for the elucidation of their planar structures. Their absolute configurations were elucidated on the basis of electron circular dichroism (ECD) techniques combined with the P/M helicity rule for the 2,3-dihydrobenzofuran chromophore, and saccharide hydrolysis.

Two New Enantiomers of Phenylethanoid and Their Anti-Inflammatory Activities.

In this phytochemical investigation, two pairs of new phenylethanoid derivative enantiomers (1a/1b and 2a/2b), a new phenylethanoid derivative 3b, and seven known compounds (3a, 4-9) were isolated from the leaves of Picrasma quassioides. Spectroscopic techniques were used for the elucidation of their chemical structures, and the absolute configurations were determined by a comparison between the experimental and calculated ECD data, as well as the application of Snatzke's method. Compounds (1a/1b-3a/3b) were measured for their production of NO levels in LPS-induced BV-2 microglial cells.

Structure elucidation and absolute configuration determination of C, C and C tirucallane triterpenoids from the leaves of Picrasma quassioides (D. Don) Benn.

Seven undescribed tirucallane-type triterpenoids, kumunorquassins A‒E and kumuquassins K and L, along with nine known analogues, have been isolated from the leaves of Picrasma quassioides (D. Don) Benn. Their structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD).

Isolation and structure elucidation of anti-tyrosinase compounds from the seeds of .

Three new compounds, crotalariapallins A-C (), were isolated from the 95% EtOH extract of the seeds of . Their structures were established based on extensive spectroscopic methods, including HRESIMS, UV, 1D and 2D NMR. All compounds were evaluated for their inhibitory activities to tyrosinase.

Seven new neuroprotective sesquineolignans isolated from the seeds of Crataegus pinnatifida.

The investigation of the ethanol extract of the seeds of Crataegus pinnatifida led to the isolation of seven new 8-O-4' type sesquineolignans crasesquineolignan A-G (1-7), along with a reported analogue, leptolepisol B (8). The chemical structures of these compounds were elucidated based on complex analysis of their MS, 1D and 2D NMR data. All the isolated compounds were tested for their neuroprotective effects against the damage of human neuroblastoma SH-SY5Y cells induced by HO, and most of them showed significant neuroprotective activity.