Five macrocyclic glycosides from <i>Schoenoplectus tabernaemontani</i>

<p>Macrocyclic glycosides with unique 22-membered dimeric lactone skeleton, are rare occurring natural products. There are only ten compounds reported so far. Herein we reported the isolation and characterisation of five macrocyclic glycosides from <i>Schoenoplectus tabernaemontani</i>, including three new compounds (Schoenopolide A-C, <b>1–3)</b> and two known ones, Berchemolide (<b>4</b>) and Clemoarmanoside B (<b>5</b>). Their structures were established on the basis of extensive analysis of spectroscopic data. In addition, the anti-oxidative activity of Berchemolide (<b>4</b>) against H₂O₂-induced of renal tubular epithelial (HK-2) cells was also evaluated.</p

Diaporpyrone E, an undescribed α-pyrone from the endophytic fungus <i>Diaporthe</i> sp. CB10100

An undescribed α-pyrone diaporpyrone E (1), and three known nucleotides, 5’-O-acetyl uridine (2), 5’-O-acetyl thymidine (3), and adenine (4), were identified from Diaporthe sp. CB10100, an endophytic fungus isolated from the medicinal plant Sinomenium acutum. The structure of 1 was determined by extensive analysis of its HRMS, 1D and 2D NMR spectroscopic data, as well as electronic circular dichroism calculations and comparison. The in vitro cytotoxic and antibacterial assays of 1 revealed that it has a 30.2% inhibitory effect on HepG2 cells at 50 μM, while no antibacterial activities against Staphylococcus aureus and Klebsiella pneumoniae at 64 μg/mL.</p

Discovery and Biosynthetic Studies of a Highly Reduced Cinnamoyl Lipid, Tripmycin A, from an Endophytic <i>Streptomyces</i> sp.

A Tripterygium wilfordii endophyte, Streptomyces sp. CB04723, was shown to produce an unusually highly reduced cytotoxic cinnamoyl lipid, tripmycin A (1). Structure–activity relationship studies revealed that both the cinnamyl moiety and the saturated fatty acid side chain are indispensable to the over 400-fold cytotoxicity improvement of 1 against the triple-negative breast cancer cell line MDA-MB-231 compared to 5-(2-methylphenyl)-4-pentenoic acid (2). Bioinformatical analysis, gene inactivation, and overexpression revealed that Hxs15 most likely acted as an enoyl reductase and was involved with the side chain reduction of 1, which provides a new insight into the biosynthesis of cinnamoyl lipids