Rapid Evaporation Solutions for Natural Product Extraction Processes - John Hester

Working with natural products as candidates for pharmaceutical leads has a reputation of being very difficult. Sample collection, preparation, extraction, and drying is extremely labour intensive and not easily reproducible from a process standpoint. The traditional bottleneck in the natural product pipeline has been the drying of solvent extracted sample. Recently, the use of new technology has facilitated and sped up this process, helping to eliminate the bottleneck.

The National Center for Natural Products Research (NCNPR), a research entity within the School of Pharmacy at the University of Mississippi, has a long history of discovering novel compounds from natural products. NCNPR has a dedicated team of research scientists whose expertise is very diverse. Teams of botanists, biologists, and chemists have developed models to identify and isolate new active components from natural products. The repository at the NCNPR is responsible for producing plant extract for such research efforts.

Repository Natural Product Process
Teams of botanists who harvest plant material and create the taxonomic vouchers for our expanding plant collection harvest plants or marine organisms. These samples are lyophilised and ground, and stored in our repository. Each sample is weighed out and extracted with ethanol using the Dionex ASE®300 (Accelerated Solvent Extraction) unit. The unit has been programmed to repeat the extraction process to ensure we remove as much of the organic material as possible. This extracted material is collected in 250 mL glass bottles. This extracted solvent is dried using various pieces of equipment until the sample is condensed to a typically dark, crude ‘sludge’.

This process is an art rather than an exact science. The Associate R&D Chemist who conducts this work has to make a judgment call to determine how much plant material is needed to generate enough crude extract ‘sludge’ for our bioassay work. Often times, the same sample is extracted again or another sample is extracted to achieve this required amount. This ‘sludge’ is used for primary bioassay discovery. Results from these efforts dictate which natural products are fractionated for further work. These fractions are also screened in our bioassays. Again, the active fractions are isolated to identify the pure compound(s) for verification of activity again in the bioassays. Once a novel pure compound has identified, synthetic chemists work to scale up synthesis for further work.