Microbial Transformations Of Bioactive Compounds

Volume 1: Notes on the historical development of microbial transformations; The methodology of microbial transformations of organic compounds; Microbial transformations of antibiotics; Microbial transformation of important industrial hydrocarbons; Microbial transformations of prostaglandins. Volume 2: Microbial transformations as a means of preparing mammalian drug metabolites; Transformations of xenobiotics by the intestinal microflora; Microbial transformations of alkaloids; Microbial transformations of cannabinoids; Microbial transformations of pesticides.

The volume reviews different types of bioactive components associated with food fermentation and their impact on human health. The diversity of microorganism responsible for the production of different types of fermented foods and beverages includes bacteria, yeasts, and fungi. Biotransformation of food constituent by microorganisms occurs during fermentation processes for the production of fermented food and in the gastrointestinal tract by gut microorganisms. This biotransformation results in production of specific bioactive compounds that are responsible for a wide range of health benefits. The bioactive compounds discussed in this book includes polyphenols, bioactive peptides, fibrinolytic enzymes, gama-amino butyric acids (GABA) exopolysaccharides, probiotic, prebiotic, symbiotic and antinutritional factors. These bioactive compounds are responsible for health benefits such as antioxidant, antihypertension, antimicrobial, cholesterol lowering, anticancer, obesity and antithrombotic properties. Advanced research in the field of food fermentation and their health benefits have resulted in commercialization of some of the fermented foods as functional foods. The traditional fermented foods consumed in different parts of the world and their health benefits are discussed in detail and the book concludes with recent advances in microbial transformation during gut fermentation and their impact on human health. There has been increasing interest among researchers on the proposed title in the last decade and the book brings updated information on research and advances in different types of health benefits exhibited by bioactive compounds in a wide range of fermented foods.

Natural products play an integral and ongoing role in promoting numerous aspects of scientific advancement, and many aspects of basic research programs are intimately related to natural products. The significance, therefore, of the Studies in Natural Product Chemistry series, edited by Professor Atta-ur-Rahman, cannot be overestimated. This volume, in accordance with previous volumes, presents us with cutting-edge contributions of great importance.

We are very pleased to introduce the Book Version of our Special Issue in Molecules dedicated to the memory of the late Professor Dr. Charles D. Hufford. The issue has been a huge success, with 22 full-length peer-reviewed papers and a tribute by Professor Alice M.Clark. Authors, reviewers, and collaborators from many countries across the worldhave contributed to this endeavour, and we are truly grateful to all. This Special Issue isrepresentative of the broad impact that “Charlie” had on the field of bioactive naturalproducts. This Special Issue comprises papers from Professor Hufford’s former students,colleagues, and collaborators throughout the world who have utilized a wide array ofstate-of-the-art techniques to examine diverse natural sources to isolate and identify avariety of natural products with a wide spectrum of biological activities, including somenew microbial transformations and insights into bioactive molecules. Many new bioactive compounds are described and reported here for the first time. Bioactivities reportedinclude cytotoxicity, antimicrobial activity, anti-inflammatory activity, antileishmanialactivity, antitrypanosomal activity, antimalarial activity, analgesic activity, and beneficialliver activities, just to name a few. This Special Issue will undoubtedly have a lasting impact on the field of bioactive natural products, as exemplified by the career of Dr. Hufford. Lastly, without the timely and outstanding contributions from all of you, this Special Issue would not have been possible. We thank you all very much for your contributions and your time devoted to this Special Issue in memory of a special person. Finally, we express ourgratitude and thanks to the journal Molecules and their excellent team of expert reviewers for giving us the support and opportunity to make this Special Issue a huge success!

Biotransformation of natural, synthetic, and semi-synthetic compounds has emerged as a frontier branch of chemical sciences that is progressively being applied in numerous fields. In the present review, we have summarized our biotransformation studies on bioactive compounds from 1997 to 2022. Various microbial and plant cell cultures were used for biocatalytic structural transformations. We present here an overview of biotransformation of 53 compounds belonging to various classes of natural, synthetic, and semi-synthetic compounds, published in several leading journals. The structures of the resulting metabolites have been elucidated by detailed spectroscopic studies. Oxidation, reduction, dehydrogenation, chlorination, aromatization, methylation, demethylation, rearrangements, etc. were the main reactions that occurred during the biotransformation processes. Many of the biotransformed products exhibited interesting biological activities. Structural transformations in some cases have also led to improved pharmacokinetic profiles. This review is aimed to provide a focused account of extensive work carried out in our laboratories in this field, as well as the immense potential of biocatalytic transformations in organic chemistry.

Microorganisms have had a long and surprising history. They were “invisible” until invention of microscope in the 17th century. Until that date, although they were extensively (but inconsciously) employed in food preservation, beer and wine fermentation, cheese, vinegar, yogurt and bread making, as well as being the causative agents of infectious diseases, they were considered as “not-existing”. The work of Pasteur in the middle of the 19th century revealed several biological activities performed by microorganisms including fermentations and pathogenicity. Due to the urgent issue to treat infectious diseases (the main cause of death at those times) the “positive potential” of the microbial world has been neglected for about one century. Once the fight against the “evil” strains was fulfilled also thanks to the antibiotics, industry began to appreciate bacteria’s beneficial characteristics and exploit selected strains as starters for both food fermentations and aroma, enzyme and texturing agent production. However, it was only at the end of the 20th century that the probiotic potential of some bacteria such as lactic acid bacteria and bifidobacteria was fully recognized. Very recently, apart from the probiotic activity of in toto bacteria, attention has begun to be directed to the chemical mediators of the probiotic effect. Thanks also to the improvement of techniques such as transcriptomics, proteomics and metabolomics, several bioactive compounds are continuously being discovered. Bioactive molecules produced by bacteria, yeasts and virus-infected cells proved to be important for improving or impairing human health. The most important result of last years’ research concerns the discovery that a very complex network of signals allows communication between organisms (from intra-species interactions to inter-kingdom signaling). Based on these findings a completely new approach has arisen: the system biology standpoind. Actually, the different organisms colonizing a certain environmental niche are not merely interacting with each other as individuals but should be considered as a whole complex ecosystem continuously exchanging information at the molecular level. In this context, this topic issue explores both antagonistic compounds (i.e. antibiotics) and “multiple function” cooperative molecules improving the physiological status of both stimulators and targets of this network. From the applicative viewpoint, these molecules could be hopefully exploited to develop new pharmaceuticals and/or nutraceuticals for improving human health.