National Cancer Institute (NCI) Program for Natural Products Discovery: Rapid Isolation and Identification of Biologically Active Natural Products from the NCI Prefractionated Library

This paper introduces an automated, high-capacity, and high-throughput procedure developed by the National Cancer Institute (NCI) for the rapid isolation and identification of biologically active natural products from a prefractionated library. The core of the method involves a semipreparative HPLC approach that processes 1 mg of a primary hit fraction to yield 22 subfractions in an assay-ready format. This streamlined process significantly reduces the time and material typically required for natural product drug discovery. Following initial screening, active fractions undergo comprehensive analysis using Nuclear Magnetic Resonance (NMR), Liquid Chromatography-Mass Spectrometry (LCMS), and Fourier-Transform Infrared Spectroscopy (FTIR) to elucidate the structural classes of the active principles. The study demonstrates the efficiency of this workflow in generating subfractions, the speed of structural elucidation, and its capability to quickly isolate and identify novel, biologically active natural products. A key advantage is the ability to detect and isolate minor yet potent natural products, as exemplified by the successful isolation of swinholide A, even at a low yield of 0.017% from the crude extract. This innovative approach not only conserves valuable extract mass and reduces chemist time but also integrates structural knowledge early in the isolation process, thereby accelerating the overall drug discovery pipeline.

This paper introduces an automated, high-capacity, and high-throughput procedure developed by the National Cancer Institute (NCI) for the rapid isolation and identification of biologically active natural products from a prefractionated library. The core of the method involves a semipreparative HPLC approach that processes 1 mg of a primary hit fraction to yield 22 subfractions in an assay-ready format. This streamlined process significantly reduces the time and material typically required for natural product drug discovery. Following initial screening, active fractions undergo comprehensive analysis using Nuclear Magnetic Resonance (NMR), Liquid Chromatography-Mass Spectrometry (LCMS), and Fourier-Transform Infrared Spectroscopy (FTIR) to elucidate the structural classes of the active principles. The study demonstrates the efficiency of this workflow in generating subfractions, the speed of structural elucidation, and its capability to quickly isolate and identify novel, biologically active natural products. A key advantage is the ability to detect and isolate minor yet potent natural products, as exemplified by the successful isolation of swinholide A, even at a low yield of 0.017% from the crude extract. This innovative approach not only conserves valuable extract mass and reduces chemist time but also integrates structural knowledge early in the isolation process, thereby accelerating the overall drug discovery pipeline. Research Background and Significance Natural products have historically been a rich source of bioactive compounds for drug discovery, particularly in oncology. However, the complexity of natural extracts and the low abundance of potent constituents have often posed significant challenges for rapid identification and isolation of active compounds. Tra