Penicisteckins A-F, Isochroman-Derived Atropisomeric Dimers from Penicillium steckii HNNU-5B18.

Penicisteckins A-D (1-4), two pairs of atropodiastereomeric biaryl-type hetero- and homodimeric bis-isochromans with 7,5'- and 7,7'-linkages and a pair of atropodiastereomeric 2-(isochroman-5-yl)-1,4-benzoquinone derivatives [penicisteckins E (5) and F (6)], were isolated from the Penicillium steckii HNNU-5B18. Their structures including the absolute configuration were determined by extensive spectroscopic and single-crystal X-ray diffraction analysis and TDDFT-ECD calculations. Both the bis-isochromans and the isochroman/1,4-benzoquinone conjugates represent novel biaryl scaffolds containing both central and axial chirality elements. The monomer anserinone B (8) exhibited potent antibacterial activities against Staphylococcus aureus ATCC 29213 and methicillin-resistant Staphylococcus aureus with minimal inhibition concentration values ranging from 2 to 8 µg mL-1. Plausible biosynthetic pathways of 1-6 are proposed, which suggest how the absolute configurations of the isolates were established during the biosynthetic scheme.

Two novel nornemoralisin-type diterpenoids from Aphanamixis polystachya (Wall.) R. Parker.

Two novel heptanornemoralisin-type diterpenoids nornemoralisins A (1) and B (2), together with two known compounds nemoralisin (3) and nemoralisin A (4), were isolated from the stem bark and leaves of Aphanamixis polystachya (Wall.) R. Parker. Their structures were established through comprehensive analyses of NMR spectroscopic data and high resolution mass spectrometric (HR-ESI-MS) data. The absolute configurations of carbon stereocenters were elucidated by circular dichroism (CD) analyses. The four compounds were tested for their potential cytotoxic effects against ACHN, HeLa, SMMC-7721, and MCF-7 cell lines. Nornemoralisins A (1) and B (2) exhibited significant cytotoxicity on ACHN with an IC50 value of 13.9 ± 0.8 and 10.3 ± 0.4 µM, respectively, and other compounds failed to reveal obvious cytotoxicity on the tested cell lines, compared to positive control vinblastine (IC50, 28.0 ± 0.9 µM).

Isopimarane-type diterpenoids from Croton laevigatus.

A new isopimarane-type diterpenoid, crolaevinoid A, along with four known analogues was isolated from the twigs and leaves of Croton laevigatus. The structures of the isolated compounds were established on the basis of NMR and MS spectroscopic analyses. The isolated compounds were examined the antibacterial activities. Unfortunately, the compounds showed no antibacterial activity against Micrococcus luteus, Methicillin-resistant Staphylococcus aureus, Aeromonas hydrophila, Klebsiella pneumoniae ssp pneumoniae, Acinetobacter Baumanii, and Escherichia coli.

Chemical constituents from common vetch (Vicia sativa L.) and their antioxidant and cytotoxic activities.

Vicia sativa L. (common vetch) is a potential food source for both human beings and animals because of its abundant nutritional composition. There is a lack of phytochemical study on the whole plant, and thus the objective of this study was to investigate the isolation of phytochemicals and evaluate their biological activities. A new flavanol, (2R,3S)-3,3'-dihydroxy-4',7-dimethoxyflavanol (1), together with nine known compounds, two flavones (2-3), one coumarin (4), and six oleanane triterpenoids (5-10), was obtained from Vicia sativa L.. The structure of the new compound 1 was determined via its NMR spectra, IR and CD data. Compound 3 displayed the potential of the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect in antioxidant test. In terms of cytotoxic activities, compound 3 showed moderate cytotoxic activities against three human tumor cells, especially HeLa cells.

Iridoid Derivatives with Cytotoxic Activity from Pedicularis uliginosa Bunge.

Three new iridoids, rel-(4aR,7S,7aS)-7-hydroxy-7-methyl-1,4a,5,6,7,7a-hexahydrocyclopenta[c]pyran-4-carbaldehyde (1), 1-methoxy-7-methyl-1,3,5,6-tetrahydrocyclopenta[c]pyran-4-carbaldehyde (2), and rel-(1R,4S,4aS,7R,7aR)-7-methylhexahydro-1,4-(epoxymethano)cyclopenta[c]pyran-3(1H)-one (3), together with seven known analogues, were isolated from the 95 % EtOH extract of the whole plants of Pedicularis uliginosa Bunge. Their structures were elucidated via extensive NMR spectroscopy and mass spectral data. In terms of inhibitory effects on human tumor cells, compounds 1, 2, 6, 7, and 8 exhibited better inhibitory activities against ACHN cells than the positive control (vinblastine).