A RuAAC-Based Fluorescent Labeling Strategy for Efficient Detection of Alkyne-Containing Natural Products
Yan-Peng Liang1,2, Rui Ma1, Haixia Zhang3
1Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (CAS), Lanzhou730000, P. R. China.
Analytical Chemistry
|July 20, 2026
Summary
A new ruthenium-catalyzed reaction enables fluorescent labeling of both internal and terminal alkyne-containing natural products (ANPs). This rapid, high-throughput method accelerates the discovery of valuable ANPs from medicinal plants.
Area of Science:
- Natural product chemistry
- Drug discovery
- Chemical biology
Background:
- Natural products (NPs) are vital for drug discovery, with alkyne-containing NPs (ANPs) showing diverse bioactivities.
- Current screening methods struggle with ANP discovery due to low abundance, instability, and limitations in detecting internal alkynes.
- Existing fluorescent labeling relies on copper-catalyzed azide-alkyne cycloaddition (CuAAC), which cannot detect internal alkyne-containing natural products (IANPs).
Purpose of the Study:
- To develop an efficient and selective fluorescent labeling strategy for comprehensive ANP discovery.
- To overcome the limitations of existing methods in detecting both terminal and internal alkynes.
- To establish a rapid, high-throughput screening approach for ANPs in complex mixtures.
Main Methods:
- Developed a novel fluorescent labeling strategy using ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) with 3-azido-7-hydroxycoumarin.
- Optimized RuAAC conditions for mild reaction parameters (20 °C, 5 h), enabling simultaneous detection of IANPs and TANPs.
- Applied the method to screen 22 medicinal plant samples and validated findings using MALDI TOF-MS.
Main Results:
- The RuAAC method achieved low detection limits (3.95 μM for IANPs, 1.55 μM for TANPs) with broad substrate tolerance and high selectivity.
- Screening of 22 medicinal plants identified seven samples with significant fluorescence enhancement, indicating ANP presence.
- MALDI TOF-MS confirmed the presence of labeled ANPs in the positive plant samples, validating the assay's accuracy.
Conclusions:
- The developed RuAAC-based fluorescent labeling strategy provides a rapid, efficient, and high-throughput method for comprehensive ANP discovery.
- This approach overcomes the bottleneck of detecting IANPs, enabling broader screening of ANP potential.
- The method holds significant promise for accelerating the identification of novel lead compounds from natural product sources.
