Herein, the catalytic promiscuity of TcCGT1, a new C‐glycosyltransferase (CGT) from the medicinal plant Trollius chinensis is explored. TcCGT1 could efficiently and regio‐specifically catalyze the 8‐C‐glycosylation of 36 flavones and other flavonoids and could also catalyze the O‐glycosylation of diverse phenolics. The crystal structure of TcCGT1 in complex with uridine diphosphate was determined at 1.85 Å resolution. Molecular docking revealed a new model for the catalytic mechanism of TcCGT1, which is initiated by the spontaneous deprotonation of the substrate. The spacious binding pocket explains the substrate promiscuity, and the binding pose of the substrate determines C‐ or O‐glycosylation activity. Site‐directed mutagenesis at two residues (I94E and G284K) switched C‐ to O‐glycosylation. TcCGT1 is the first plant CGT with a crystal structure and the first flavone 8‐C‐glycosyltransferase described. This provides a basis for designing efficient glycosylation biocatalysts.

Herein, the catalytic promiscuity of TcCGT1, anew C-glycosyltransferase (CGT) from the medicinal plant Trollius chinensis is explored. TcCGT1 could efficiently and regiospecifically catalyze the 8-C-glycosylation of 36 flavones and other flavonoids and could also catalyze the O-glycosylation of diverse phenolics.The crystal structure of TcCGT1 in complex with uridine diphosphate was determined at 1.85 resolution. Molecular docking revealed an ew model for the catalytic mechanism of TcCGT1, which is initiated by the spontaneous deprotonation of the substrate.T he spacious binding pocket explains the substrate promiscuity,and the binding pose of the substrate determines C-or O-glycosylation activity.S itedirected mutagenesis at two residues (I94E and G284K) switched C-to O-glycosylation. TcCGT1 is the first plant CGT with ac rystal structure and the first flavone 8-Cglycosyltransferase described. This provides abasis for designing efficient glycosylation biocatalysts.

In an attempt to discover bioactive agents from the herbal medicine Glycyrrhiza glabra (widely known as licorice), 11 new phenolic compounds, glycybridins A-K (1-11), along with 47 known phenolics (12-58) were isolated. Their structures were elucidated on the basis of extensive NMR and MS analyses as well as experimental and computed ECD data. According to the clinical therapeutic effects of licorice, enzyme or cell-based bioactivity screenings of 1-58 were conducted. A number of compounds significantly activate Nrf2, inhibit tyrosinase or PTP1B, inhibit LPS-induced NO production and NF-κB transcription, and inhibit the proliferation of human cancer cells (HepG2, SW480, A549, MCF7). Glycybridin D (4) showed moderate cytotoxic activities against the four cancer cell lines, with IC values ranging from 4.6 to 6.6 μM. Further studies indicated that 4 (10 mg/kg, ip) decreased tumor mass by 39.7% on an A549 human lung carcinoma xenograft mice model, but showed little toxicity.

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