http://www.mdpi.com/journal/molecules/special_issues/pre-fractionation/ Summary Natural products provide an unparalleled source of chemical diversity for discovery of important and interesting biologically active molecules. This bounty comes at a price, since crude extracts of natural products can be difficult to screen in bioassays, and must be fractionated with guidance from the bioassay to obtain pure compounds. If the active compounds are present in trace amounts this can become a very difficult and time-consuming process, or the activity may be missed altogether. Numerous companies and academic groups have therefore sought to remedy these problems by chromatographically separating the extract to various degrees of resolution. This issue will examine a spectrum of different approaches and provide details on the technical challenges involved, the costs, and the rewards in improved identification of novel natural products. Leading papers Eldridge, G. R.; Vervoort, H. C.; Lee, C. M.; Cremin, P. A.; Williams, C. T.; Hart, S. M.; Goering, M. G.; O'Neil-Johnson, M.; Zeng, L. High-throughput method for the production and analysis of large natural product libraries for drug discovery. Anal.Chem. 2002, 74 (16), 3963-3971. Bindseil, K. U.; Jakupovic, J.; Wolf, D.; Lavayre, J.; Leboul, J.; van der Pyl, D. Pure compound libraries; a new perspective for natural product based drug discovery. Drug Discov. Today 2001, 6 (16), 840-847. Submission All papers should be submitted to molecules@mdpi.org with copy to the guest editor. To be published continuously until the deadline and papers will be listed together at the special websites. Submitted papers should not have been previously published nor be currently under consideration for publication elsewhere. All papers are refereed through a peer review process. A guide for authors, sample copies and other relevant information for submitting papers are available on the Instructions for Authors page. Molecules is an international peer-reviewed quarterly journal published by Molecular Diversity Preservation International. Please visit the Instructions for Authors page before submitting a paper. Open Access publication fees are 800 CHF per paper. English correction fees (250 CHF) will be added in certain cases (1050 CHF per paper for those papers that require extensive additional formatting and/or English corrections.). http://www.mdpi.com/1420-3049/13/6/1406/ From the beginning of the antibiotic era in the 1940s to the present, Wyeth has sustained an active research program in the area of natural products discovery. This program has continually evolved through the years in order to best align with the “current” drug discovery paradigm in the pharmaceutical industry. The introduction of highthroughput screening and the miniaturization of assays have created a need to optimize natural product samples to better suit these new technologies. Furthermore, natural product programs are faced with an ever shortening time period from hit detection to lead characterization. To address these issues, Wyeth has created a pre-fractionated natural products library using reversed-phase HPLC to complement their existing library of crude extracts. The details of the pre-fractionated library and a cost-benefit analysis will be presented in this review. http://www.mdpi.com/1420-3049/13/6/1406/ Fri, 20 Jun 2008 00:00:00 CEST Molecules 2008-06-20 13 6 Article 1406 1426 1420-3049 Pre-fractionated Microbial Samples – The Second Generation Natural Products Library at Wyeth 2008-06-20 doi: 10.3390/molecules13061406 Melissa M. Wagenaar http://www.mdpi.com/1420-3049/13/6/1372/ The high-throughput screening and drug discovery paradigm has necessitated a change in preparation of natural product samples for screening programs. In an attempt to improve the quality of marine natural products samples for screening, several fractionation strategies were investigated. The final method used HP20SS as a solid support to effectively desalt extracts and fractionate the organic components. Additionally, methods to integrate an automated LCMS fractionation approach to shorten discovery time lines have been implemented. http://www.mdpi.com/1420-3049/13/6/1372/ Thu, 19 Jun 2008 00:00:00 CEST Molecules 2008-06-19 13 6 Article 1372 1383 1420-3049 Fractionated Marine Invertebrate Extract Libraries for Drug Discovery 2008-06-19 doi: 10.3390/molecules13061372 Tim S. Bugni Mary Kay Harper Malcolm W.B. McCulloch Jason Reppart Chris M. Ireland