Aculebiphenyl A-B, new biphenyl derivatives from Ruscus aculeatus.

The investigation of chemical constituents from the rhizomes of Ruscus aculeatus resulted in the isolation of two new biphenyl derivatives, aculebiphenyls A and B (1-2), together with two known analogs (3-4). Their chemical structures were elucidated based on extensive spectroscopic interpretation and HR-ESI-MS analysis. Compounds 3-4 were isolated from the Ruscus genus for the first time. The isolated compounds were tested for anti-inflammatory activities and antibacterial activities. Compound 1 exhibited significant inhibitory effects on LPS-induced NO production and COX-2 with IC50 values of 10.8 µM and 0.4 µM. Compound 1 also significantly down-regulated the levels of inflammatory cytokines IL-1ß, IL-6, and TNF-α. Compound 1 showed moderate antibacterial activities.

Apoptotic effects of phenols from the twigs and leaves of Garcinia nujiangensis.

In order to find potential agents for treating cancer disease in naturally occurring compounds, we conducted a systematic phytochemical investigation on the endemic species of Garcinia nujiangensis. Three new biphenyl derivatives (1-3) and one new polycyclic polyprenylated benzophenone (4), together with four known benzophenone analogues (5-8), have been isolated from the CH2Cl2 extract of the twigs and leaves of G. nujiangensis. Their structures were determined by detailed spectroscopic analyses and comparison with structurally related known analogues. Experimental and calculated ECD method was used to determine the absolute configuration of 1 and 4. Moreover, compounds 5-7 were isolated for the first time from this species. The cytotoxicities of the new compounds were evaluated using HL-60, HepG2, and A549 human cancer cell lines. Compound 4 showed more significant antiproliferative effects against HepG2 cells with an IC50 value of 11.38 ± 0.79 µM than that of three biphenyl derivatives. The morphological features of apoptosis were evaluated in 4-treated HepG2 cells. Compound 4 effectively prevented the cell cycle progression of HepG2 cells in G2 phase. Additionally, western blot analysis indicated that treatment of 4 on HepG2 cells led to decreased expression of anti-apoptotic Bcl-2 and pro-Caspase-3, and increased protein expression of both pro-apoptotic Bax and cleaved PARP with reference to ß-actin. Overall, our results suggested that the active polycyclic polyprenylated benzophenone derivatives in the twigs and leaves of G. nujiangensis can be used as a valuable source of bioactive compounds for the pharmaceutical industry.

Inhibitory Mechanism of Prenylated Flavonoids Isolated from Mulberry Leaves on α-Glucosidase by Multi-Spectroscopy and Molecular Dynamics Simulation.

Flavonoids have always been considered as the chemical basis for the hypoglycemic effect of mulberry leaves. In the course of our search for hypoglycemic effect agents from natural sources, a systematic study was launched to explore prenylated flavonoids from mulberry leaves. Herein, chemical investigation led to the isolation of 10 characteristic prenylated flavonoids, including two new compounds (1 and 3). Their structures were elucidated based on spectroscopic data. All compounds exhibited good α-glucosidase inhibitory activity in vitro, among which compound 2 had the best activity (IC50 = 2.6 µM), better than acarbose (IC50 = 19.6 µM). Additional in vivo tests have further demonstrated compound that compound 2 has a good ability to reduce postprandial blood glucose. Then, multi-spectroscopic methods and molecular simulation studies were used to study the inhibition mechanism. The results showed that compound 2 was a mixed inhibition of α-glucosidase and the binding process was spontaneous, with van der Waals forces as the main driving force, followed by hydrogen bonding and electrostatic forces. The above studies enriched the chemical basis of mulberry leaves, and the application of computational chemistry also provided a reference for future research on such structures.