Characterization of a 4'-O-rhamnosyltransferase and de novo biosynthesis of bioactive steroidal triglycosides from Paris polyphylla.

Steroidal saponins in Paris polyphylla featuring complicated sugar chains exhibit notable biological activities, but the sugar chain biosynthesis is still not fully understood. Here, we identified a 4'-O-rhamnosyltransferase (UGT73DY2) from P. polyphylla, which catalyzes the 4'-O-rhamnosylation of polyphyllins V and VI, producing dioscin and pennogenin 3-O-β-chacotrioside, respectively.

From Monocyclization to Pentacyclization: A Versatile Plant Cyclase Produces Diverse Sesterterpenes with Anti-Liver Fibrosis Potential.

A prolific multi-product sesterterpene synthase CbTPS1 is characterized from the medicinal Brassicaceae plant Capsella bursa-pastoris. Twenty different sesterterpenes including 16 undescribed compounds, possessing 10 different mono-/di-/tri-/tetra-/penta-carbocyclic skeletons, including the unique 15-membered macrocyclic and 24(15→14)-abeo-capbuane scaffolds, are isolated and structurally elucidated from engineered Escherichia coli strains expressing CbTPS1. Site-directed mutagenesis assisted by molecular dynamics simulations resulted in the variant L354M with up to 13.

Anti-Inflammatory Secoiridoids from the Medicinal Herb Gentianopsis barbata.

Five new secoiridoids, gentianopsins A-E (1-5), along with two known analogues (6 and 7) were isolated from the whole plants of the medicinal herb Gentianopsis barbata. Their structures were elucidated by a comparison of extensive spectroscopic analysis (1D and 2D NMR, and HRMS) and quantum chemical calculations. Gentianopsins A (1) and B (2) represented two unusual skeletons of trihomo-secoiridoids.

Antioxidant and anti-Alzheimer's disease activities of 1,8-cineole and its cyclodextrin inclusion complex.

1,8-Cineole is a bicyclic monoterpene widely distributed in the essential oils of various medicinal plants, and it exhibits significant anti-inflammatory and antioxidant activities. We aimed to investigate the therapeutic effect of 1,8-cineole on anti-Alzheimer's disease by using transgenic Caenorhabditis elegans models. Our studies demonstrated that 1,8-cineole significantly relieved Aβ-induced paralysis and exhibited remarkable antioxidant and anti-Aβ aggregation activities in transgenic nematodes CL4176, CL2006 and CL2355.