Bioactive phenylpropanoid derivatives from the fruits of Lycium ruthenicum Murr.

Eight new (1-7 and 15) and 18 known (8-14 and 16-26) phenylpropanoid derivatives were isolated from the fruits of Lycium ruthenicum Murr. (black wolfberry). Their structures were determined by comprehensive spectroscopic analyses, chemical methods, and comparisons of spectroscopic data. Four known compounds (16, 17, 24, and 26) were firstly isolated from the genus Lycium. Interestingly, compounds 1/2 and 4/5 were isolated as two pairs of inseparable anomers owing to the tautomerism of the free hemiacetal at C-1'' in solution. The antioxidant, α-glucosidase inhibitory, and acetylcholinesterase (AChE) inhibitory activities of compounds 1-26 were evaluated. Some compounds possessed DPPH radical scavenging activity, and all compounds (1-26) exhibited different levels of oxygen radical absorbance capacity (ORAC). One compound displayed α-glucosidase inhibitory activity with potency close to that of the positive control (acarbose).

Cycloartane-type triterpenoids from the root of Astragalus membranaceus var. mongholicus.

Three new (1-3) and 11 known (4-14) cycloartane-type triterpenoids were isolated from the root of Astragalus membranaceus var. mongholicus. Their structures were determined by spectroscopic analyses and chemical methods. Cycloartane-type triterpenoids are a class of major bioactive constituents in the root of A. membranaceus var. mongholicus, and the discovery of compounds 1-3 added new members of this kind of natural product. [Formula: see text].

N-methoxy-ß-carboline alkaloids with inhibitory activities against Aß42 aggregation and acetylcholinesterase from the stems of Picrasma quassioides.

Nine new N-methoxy-ß-carboline alkaloids (NMCAs) (1a/1b-3a/3b and 4-6) and two known NMCAs (7 and 8) were isolated from the stems of Picrasma quassioides. Their structures were elucidated by spectroscopic data analyses, quantum chemical calculations, and single-crystal X-ray crystallographic data. An analysis of the 13C NMR chemical shifts of the N-methoxy groups in these NMCAs and 41 gathered known compounds reveals the phenomenon that the chemical shifts of all these N-methoxy groups are greater than δC 62, which can be used to recognize the N-methoxy group rapidly. In addition, the acetylcholinesterase (AChE) and Aß42 aggregation inhibitory activities of 1-8 were evaluated. Compounds 1, 2, 7, and 8 displayed AChE inhibitory activity with IC50 values of 14.9, 13.2, 17.6, and 43.9 µM, respectively. Compound 2 showed inhibition activity against Aß42 aggregation with an IC50 value of 10.1 µM.