Donald B. Borders

Bio: Donald B. Borders is an academic researcher from American Cyanamid. The author has contributed to research in topics: Antiparasitic agent & Actinomadura madurae. The author has an hindex of 19, co-authored 96 publications receiving 1892 citations.

Calicheamicins, a novel family of antitumor antibiotics. 3. Isolation, purification and characterization of calicheamicins beta 1Br, gamma 1Br, alpha 2I, alpha 3I, beta 1I, gamma 1I and delta 1I.

Abstract: Novel antitumor antibiotics, calicheamicins β1Br, γ1Br, α2I, α3I, β1I, γ1I and δ1I were recovered from the fermentation broth of Micromonospora echinospora ssp. calichensis by solvent extraction, selective precipitation, normal phase, reversed phase and partition chromatography. The individual components were characterized by their UV, IR, 1H and 13C NMR spectral data.

LL-F28249 antibiotic complex: a new family of antiparasitic macrocyclic lactones ― Isolation, characterization and structures of LL-F28249 α, β, γ, λ

Abstract: A new family of antiparasitic macrolides has been isolated from Streptomyces cyaneogriseus sp. noncyanogenus. The compounds, designated LL-F28249 α, β, γ and λ, possess potent antiparasitic activity. The isolation, purification and structure determination by spectroscopic methods are presented.

Natural Products as Sources of New Drugs over the Nearly Four Decades from 01/1981 to 09/2019.

Abstract: This review is an updated and expanded version of the five prior reviews that were published in this journal in 1997, 2003, 2007, 2012, and 2016. For all approved therapeutic agents, the time frame has been extended to cover the almost 39 years from the first of January 1981 to the 30th of September 2019 for all diseases worldwide and from ∼1946 (earliest so far identified) to the 30th of September 2019 for all approved antitumor drugs worldwide. As in earlier reviews, only the first approval of any drug is counted, irrespective of how many "biosimilars" or added approvals were subsequently identified. As in the 2012 and 2016 reviews, we have continued to utilize our secondary subdivision of a "natural product mimic", or "NM", to join the original primary divisions, and the designation "natural product botanical", or "NB", to cover those botanical "defined mixtures" now recognized as drug entities by the FDA (and similar organizations). From the data presented in this review, the utilization of natural products and/or synthetic variations using their novel structures, in order to discover and develop the final drug entity, is still alive and well. For example, in the area of cancer, over the time frame from 1946 to 1980, of the 75 small molecules, 40, or 53.3%, are N or ND. In the 1981 to date time frame the equivalent figures for the N* compounds of the 185 small molecules are 62, or 33.5%, though to these can be added the 58 S* and S*/NMs, bringing the figure to 64.9%. In other areas, the influence of natural product structures is quite marked with, as expected from prior information, the anti-infective area being dependent on natural products and their structures, though as can be seen in the review there are still disease areas (shown in Table 2) for which there are no drugs derived from natural products. Although combinatorial chemistry techniques have succeeded as methods of optimizing structures and have been used very successfully in the optimization of many recently approved agents, we are still able to identify only two de novo combinatorial compounds (one of which is a little speculative) approved as drugs in this 39-year time frame, though there is also one drug that was developed using the "fragment-binding methodology" and approved in 2012. We have also added a discussion of candidate drug entities currently in clinical trials as "warheads" and some very interesting preliminary reports on sources of novel antibiotics from Nature due to the absolute requirement for new agents to combat plasmid-borne resistance genes now in the general populace. We continue to draw the attention of readers to the recognition that a significant number of natural product drugs/leads are actually produced by microbes and/or microbial interactions with the "host from whence it was isolated"; thus we consider that this area of natural product research should be expanded significantly.

The Role of Natural Product Chemistry in Drug Discovery

Abstract: Although traditionally natural products have played an important role in drug discovery, in the past few years most Big Pharma companies have either terminated or considerably scaled down their natural product operations. This is despite a significant number of natural product-derived drugs being ranked in the top 35 worldwide selling ethical drugs in 2000, 2001, and 2002. There were 15 new natural product-derived drugs launched from 2000 to 2003, as well as 15 natural product-derived compounds in Phase III clinical trials or registration at the end of 2003. Recently, there has been a renewed interest in natural product research due to the failure of alternative drug discovery methods to deliver many lead compounds in key therapeutic areas such as immunosuppression, anti-infectives, and metabolic diseases. To continue to be competitive with other drug discovery methods, natural product research needs to continually improve the speed of the screening, isolation, and structure elucidation processes, as well addressing the suitability of screens for natural product extracts and dealing with issues involved with large-scale compound supply.

Lessons from natural molecules

Abstract: Natural products have inspired chemists and physicians for millennia. Their rich structural diversity and complexity has prompted synthetic chemists to produce them in the laboratory, often with therapeutic applications in mind, and many drugs used today are natural products or natural-product derivatives. Recent years have seen considerable advances in our understanding of natural-product biosynthesis. Coupled with improvements in approaches for natural-product isolation, characterization and synthesis, these could be opening the door to a new era in the investigation of natural products in academia and industry.

Oxidative Strand Scission of Nucleic Acids: Routes Initiated by Hydrogen Abstraction from the Sugar Moiety.

Abstract: ion from the Sugar Moiety Wendy Knapp Pogozelski† and Thomas D. Tullius*,‡ Department of Chemistry, State University of New York at Geneseo, Geneseo, New York 14454, and Department of Chemistry, Boston University, Boston, Massachusetts 02215 Received August 27, 1997 (Revised Manuscript Received February 26, 1998)