Resorufin-β-D-glucuronic acid methyl ester

Resorufin-β-D-glucuronic acid methyl ester (RUG™, CAS 1415487-42-1) is a patented, dual chromogenic/fluorogenic substrate for β-glucuronidase (GUS, EC 3.2.1.31) detection, offering superior sensitivity over traditional MUG (4-methylumbelliferyl-β-D-glucuronide) for E. coli identification in food/water safety testing and microbiome analysis. The methyl ester prodrug (C19H17NO9, MW 403.34 g/mol) undergoes spontaneous/base-catalyzed hydrolysis to active resorufin-β-D-glucuronide, which β-glucuronidases (E. coli GusA, human GUSB) cleave to brightly pink/red fluorescent resorufin (Ex/Em 571/585 nm), generating intense color (stronger than X-Gluc) and fluorescence detectable by eye, plate reader, or under UV. Designed for agar plating and liquid media, RUG™ hydrolyzes via media esterases to ensure uniform substrate activation, yielding >1000-fold signal amplification with pM enzyme sensitivity and minimal background. Incorporated into ChromoSelect Broth and EC RUG media (Sigma-Aldrich), it enables rapid (4-24h) specific E. coli colony detection without confirmation tests, outperforming TBX agar in sensitivity/specificity while resisting interference from coliforms lacking gusA. Its dual-readout (absorbance 570 nm/fluorescence) supports automation in 96-well HTS for glucuronidase inhibitors, UGT1A1 phenotyping, and xenobiotic metabolism studies, with applications in environmental monitoring, dairy/pharma QC, and Gaucher disease diagnostics via GUSB activity.

Appearance

• Deep orange to red crystalline powder.
• Non-fluorescent/chromogenic until sequential hydrolysis.​

Source

• Patented chemoenzymatic synthesis (Biosynth/Discovery Finechem).
• Commercial: Sigma-Aldrich EC RUG media, Biosynth R-2155.

Molecular Weight and Structure

• Formula: C19H17NO9; MW 403.34 g/mol.
• Resorufin 7-O-β-D-glucuronopyranosyl-methyl ester (methyl ester prodrug).​

Sugar Specificity

• Specific β-D-glucuronopyranoside for bacterial/human β-glucuronidases.
• Hydrolyzed post-methyl ester cleavage; E. coli selective.​

Biological Activity

• Dual reporter: chromogenic (pink colonies) + fluorogenic (red fluorescence).
• E. coli detection sensitivity >MUG; no auto-hydrolysis.​

Purity and Microbial Contamination

• ≥90% (HPLC); microbiology grade.
• Selective for gusA+ organisms.​

Identity and Quality Control

• HRMS m/z 404 [M+H]+; hydrolysis yields resorufin confirmed 571/585 nm.
• Esterase activation verified in media.​

Shelf Life and Storage

• Stable >2 years at -18°C; formulated in ChromoSelect media.
• Light-protected dry powder.​

Applications

• E. coli detection (water/food/pharma QC); GUS reporter assays.
• HTS glucuronidase inhibitors; UGT phenotyping.​

Key Characteristics

• Dual chromo/fluorogenic; media esterase activated.
• MUG sensitivity; eye-readable pink colonies.​

Citation Links

• https://discofinechem.com/products/resorufin-beta-d-glucuronic-acid-methyl-ester/​
• https://www.biosynth.com/innovation/rug-substrate​
• https://www.sigmaaldrich.com/IN/en/product/sial/69429​
• https://www.biosynth.com/p/R-2155_P00/1415487-42-1-rug-resorufin-beta-d-glucuronic-aci​
• https://pubchem.ncbi.nlm.nih.gov/compound/Resorufin-beta-D-glucuronide-sodium-salt​
• https://www.interchim.fr/ft/A/A8DG50.pdf​
• https://patents.google.com/patent/US6534637B2/en​
• https://pubchem.ncbi.nlm.nih.gov/compound/102358581​
• https://www.sigmaaldrich.com/US/en/product/sigma/r2886​
• https://www.chemicalbook.com/ChemicalProductProperty_EN_CB2120605.htm