35775-49-6Relevant articles and documents
Metabolic products of European-type propolis. Synthesis and analysis of glucuronides and sulfates
Bloor, Stephen J.,Mitchell, Kevin A.
, (2021/04/02)
Ethnopharmacological relevance: Propolis is a bee-derived product used since antiquity for its general health-giving properties and is especially noted for its anti-bacterial activity. In more recent times, propolis has been employed against more specific targets such as antiproliferative effects vs cancer cells, wound healing and type-2 diabetes. Aim of the study: European (poplar)-type propolis from New Zealand contains a number of hydroxy cinnamic acid esters and a set of aglycone flavonoid compounds, mainly chrysin, galangin, pinocembrin and pinobanksin. Propolis is usually taken orally and propolis metabolites quickly appear in the plasma of the ingested. In this work we aimed to identify the major flavonoid plasma metabolites by direct analysis of the plasma. Materials and methods: After consumption of a large dose of propolis in a single sitting, blood samples were taken and analysed using LCMS/MS. The major flavonoid metabolites identified were also synthesised using chemical (sulfates) or enzymatic methods (glucuronides). Results: Both the sulfate and glucuronide conjugates of the four major propolis flavonoids are readily detected in human plasma after propolis ingestion. Preparation of the sulfates and glucuronides of the four major flavonoids allowed the relative proportions of the various metabolites to be determined. Although the sulfates are seen as large peaks in the LCMS/MS, the glucuronides are the dominant conjugate species. Conclusions: This study shows most of the flavonoids in the plasma are present as 7-O-glucuronides with only galangin showing some di-glucuronidation (3,7-O-diglucuronide). No evidence was found for hydroxy cinnamic acid type metabolites in the plasma samples.
Enzymatic Synthesis of Bioactive O-Glucuronides Using Plant Glucuronosyltransferases
Yue, Tian,Chen, Ridao,Chen, Dawei,Liu, Jimei,Xie, Kebo,Dai, Jungui
, p. 6275 - 6284 (2019/06/13)
Many O-glucuronides exhibiting various pharmacological activities have been found in nature and in drug metabolism. The glucuronidation of bioactive natural products or drugs to generate glucuronides with better activity and druggability is important in drug discovery and research. In this study, by using two uridine diphosphate (UDP)-dependent glucuronosyltransferases (GATs, UGT88D4 and UGT88D7) from plants, we developed two glucuronidation approaches, pure enzyme catalysis in vitro and recombinant whole-cell catalysis in vivo, to efficiently synthesize bioactive O-glucuronides by the glucuronidation of natural products. In total, 14 O-glucuronides with different structures, including flavonoids, anthraquinones, coumarins, and lignans, were obtained, 7 of which were new compounds. Furthermore, one of the biosynthesized O-glucuronides, kaempferol-7-O-β-d-glucuronide (3a), potently inhibited protein tyrosine phosphatase (PTP) 1B with an IC50 value of 8.02 × 10-6 M. Some of the biosynthesized O-glucuronides also exhibited significant antioxidant activities.
Accurate prediction of glucuronidation of structurally diverse phenolics by human UGT1A9 using combined experimental and in silico approaches
Wu, Baojian,Wang, Xiaoqiang,Zhang, Shuxing,Hu, Ming
experimental part, p. 1544 - 1561 (2012/07/27)
Purpose: Catalytic selectivity of human UGT1A9, an important membrane-bound enzyme catalyzing glucuronidation of xenobiotics, was determined experimentally using 145 phenolics and analyzed by 3D-QSAR methods. Methods: Catalytic efficiency of UGT1A9 was determined by kinetic profiling. Quantitative structure activity relationships were analyzed using CoMFA and CoMSIA techniques. Molecular alignment of substrate structures was made by superimposing the glucuronidation site and its adjacent aromatic ring to achieve maximal steric overlap. For a substrate with multiple active glucuronidation sites, each site was considered a separate substrate. Results: 3D-QSAR analyses produced statistically reliable models with good predictive power (CoMFA: q 2=0.548, r2=0.949, r pred 2 =0.775; CoMSIA: q2=0.579, r2=0.876, rpred2 =0.700). Contour coefficient maps were applied to elucidate structural features among substrates that are responsible for selectivity differences. Contour coefficient maps were overlaid in the catalytic pocket of a homology model of UGT1A9, enabling identification of the UGT1A9 catalytic pocket with a high degree of confidence. Conclusion: CoMFA/CoMSIA models can predict substrate selectivity and in vitro clearance of UGT1A9. Our findings also provide a possible molecular basis for understanding UGT1A9 functions and substrate selectivity.
