Stephtetrandrine A-D, bisbenzylisoquinoline alkaloids from Stephania tetrandra.

Four undescribed bisbenzylisoquinoline alkaloids, designated as Stephtetrandrine A-D, were isolated from the roots of Stephania tetrandra. Their structures were elucidated by IR, HRESIMS, ECD spectra, 1 D and 2 D NMR spectra and comparison with the literature data. Additional five known compounds (limacine, tetrandrine, N-trans-Feruloyltyramine, 2'-N-chloromethyltetrandrine, 2,2'-N-N-dichloromethyltetrandrine) were also isolated. N-trans-Feruloyltyramine was isolated from Stephania tetrandra for the first time. The isolated compounds were tested for monoamine oxidase, acetylcholinesterase, phosphoinositide 3-kinase α and human hepatoma cell HepG2 inhibitory activities. Stephtetrandrine C showed obvious inhibitory effect on human hepatoma HepG2, with IC50 value of 16.2 µM. Limacine and 2'-N-chloromethyltetrandrine showed moderate monoamine oxidase inhibitory effect with the IC50 values of 37.7 and 29.2 µM, respectively.

Secondary Metabolites and Biological Activities of Talaromyces sp. LGT-2, an Endophytic Fungus from Tripterygium Wilfordii.

In the present study, eleven compounds (1-11) including nine alkaloids (1-9), one triterpenoid saponin (10) and one formamide (11) were isolated from Talaromyces sp. LGT-2, an endophytic fungus from Tripterygium wilfordi. Their structures were determined based on NMR and ESI-MS spectral data, as well as comparing previous literature data. This is the first report of the isolation of alkaloids (1-9) from Talaromyces genus. In the next step, all compounds were screened for their anti-monoamine oxidase, anti-acetylcholinesterase, antibacterial and antitumor activities. Compound 11 showed moderate anti-monoamine oxidase activity with IC50 value of 61 µM; compounds 3, 4, 8 showed weaker anti-acetylcholinesterase activity; compounds 1, 3, 4, 7, 8, 9 showed moderate antibacterial activities; compounds 7, 8, 9 showed cytotoxicity against B16 cancer cell line with inhibitory rate of 86%, 82%, 78%, respectively, at the concentration of 500 µg/mL.