Polarity-guided fractionation for rapid drug discovery of plant medicines and marine therapeutics.
Challenges and Solutions
In the discovery of complex natural molecules, pure compounds will provide the clearest benefit in bioactive screens. It is, however, prohibitively expensive to isolate and purify new natural product molecules without a pre-defined biological activity. Additionally, most potent biologically active compounds often occur in trace amounts that are likely to be missed in any broad-scale purification of natural products from a complex matrix.
CXF fractionation resolves this problem by producing partially purified compounds in a rapid fashion that can be automated.
Critical Fluid Fractionation (CXF) Process
For terrestrial plants, dried, powdered biomass is first extracted with nonpolar supercritical carbon dioxide and then sequentially extracted with carbon dioxide plus increasing concentrations of a polar cosolvent such as methanol or ethanol [SuperFluids™ or SFS] in a step-wise fashion, producing fractions of increased polarity from nonpolar to totally polar.
In the fractionation of marine microorganisms, fermentation pellets are first contacted by SuperFluids™ for microbial cell disruption (as shown by the disrupted yeast cell) and secondly for the polarity-guided fractional extraction of extracellular and intracellular bioactive constituents.
CXF Increases Probability of Clean Hits
CXF enhances the drug discovery process. Research has resulted in a much higher proportion of bioactive “hits” in drug screening programs at lower than normal metabolite concentrations. CXF produces partially purified extracts and enhances the probability of clean hits.
- In comparative screening programs with the Bristol-Myers Squibb Company (BMS), research determined that the hit rate from more than 40 screens was higher in SuperFluids™ fractions than in either butanol or aqueous fractions; compare a hit rate of 2% with 1.1% and 0.6%, respectively, for butanol and aqueous supernatants. [BMS tested each of 8,320 fractions in 40 different screens for a total of 332,800 tests.]
- A blinded study was conducted with Pfizer Research Laboratories, Groton, CT to examine the ability of SuperFluids™ to extract a different set of metabolites, as compared to conventional extraction techniques. SuperFluids™ fractions had more unique peaks as compared to butanol extracts. Since the solvating properties of SuperFluids™ differ from those of conventional organic solvents, a different spectrum of metabolites was extracted.
Advantages of Using CXF for Natural Products Drug Discovery
- CXF produces a unique spectrum of secondary metabolites and reduces interference from nuisance compounds.
- CXF minimizes background noise in sensitive molecular assays and enhances the probability of clean hits.
- CXF technology (process and apparatus) has been automated for high throughput sample preparation of natural products such as marine microorganisms and medicinal plants.
- The CXF fractionation process is readily implemented in parallel units to further increase the speed of sample preparation for antiviral and anticancer screening.
- The CXF process can be readily adapted to large-scale manufacturing by CXP manufacturing technologies, which are scalable and cost-effective for complex natural product molecules.
Contracting/Partnering Opportunity/Technology Transfer
We will contract/partner with pharmaceutical and specialty chemical companies to incorporate CXF into your research and development programs.
We will also provide research-scale units to biotechnology companies, universities and research institutions to complement and improve your research and development activities.