Infectious Diseases

Ferid Murad, Atta-ur-Rahman, Ka Bian

• Publisher: Bentham Science Publishers
• Year: 2021
• ISBN:
  9789811458712
• Topic: Medicina
• Subtopic: Oncología

Herbal Medicine: Back to the Future compiles expert reviews on the application of herbal medicines (including Ayurveda, Chinese traditional medicines and alternative therapies) to treat different ailments. The book series demonstrates the use of sophisticated methods to understand traditional medicine, while providing readers a glimpse into the future of herbal medicine. This volume presents reviews of plant based therapies useful for treating different infectious diseases. The list of topics includes some niche reviews in this area including a review of the neem plant, the historical use of herbs in infectious disease therapy in Russia, and natural remedies from garlic, among other topics., The topics included in this volume are: - Improving anti-microbial activity of allicin and carvacrol through stabilized analogs and nanotechnology - Plant phenolics as an alternative source of antimicrobial compounds - Herbal medicine in Russia's history: the use of herbal medicine for infectious diseases in Russia's history - Azadirachta indica (neem) in various infectious diseases - Contribution of novel delivery systems in the development of phytotherapeutics This volume is essential reading for all researchers in the field of natural product chemistry and pharmacology. Medical professionals involved in internal medicine who seek to improve their knowledge about herbal medicine and alternative therapies for tropical and other infectious diseases will also benefit from the contents of the volume.

Plant Phenolics as an Alternative Source of Antimicrobial Compounds

Inamullah Hakeem Said^{1, *}, Nikolai Kuhnert^{1, *}

¹ Department of life sciences and Chemistry, Jacobs University Bremen, 28759 Bremen, Germany

Abstract

The use and search for new medicines and dietary supplements derived from plants have enhanced in the modern era. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. Polyphenols are natural compounds characterized by a high structural variety, and their existence in plants makes them essential components. Increasingly, resistant bacteria require the continuous need for new and effective antibiotics. This class of natural products is becoming the target of anti-infective research, and many groups have identified that phenolic compounds are possessing broad-spectrum antibacterial and antiviral activity. Owing to interest in their biological activities, both the chemical structure of the phenolic moiety and any attached chemical groups define whether the polyphenol is bioactive or not. Compared to other phenolics, flavonoids class have been abundantly used in anti-infective research.

This chapter summarizes the application of polyphenol tested by various groups against infectious diseases caused by bacteria and viruses as pathogens. The reported MIC values are presented in a concise table, which is conflicting among different groups, possibly due to assay parameters and strain variation. However, it is shown that phenolic compounds have great potentials, which requires future research for the development of novel antimicrobial or antiviral agents or aid as a synergistic agent in combination with conventional anti-infective drugs.

Keywords: Antibacterial, Antiviral, Plants, Polyphenols, Secondary metabolites.

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^* Corresponding authors Inamullah Hakeem Said & Nikolai Kuhnert: Department of life sciences and Chemistry, Jacobs University Bremen, 28759 Bremen, Germany; E-mails: [email protected] and n.kuhnert@ jacobs-university.de

INTRODUCTION

According to the European Union estimation in 2007, approximately 25,000 patients per annum die due to infection with major types of drug-resistant bacteria, which are responsible for bloodstream infection [1].

Increasingly, resistant bacteria require a continuous need for new and effective antibiotics. However, in the last two-three decades, only two new classes of antimicrobials were launched in the market. Many drug developers have left the field. The medical interventions in the 21^st century extended and improved our lives, such as anti-cancer drugs, cardiac surgery, transplantation, bone marrow transplantation and joint replacements. All mentioned interventions require strict control of infection. Although the current research could routinely add new medicines and therapies to address numerous other diseases, unfortunately, our grip on infection is loosening.

The agents (bacteria, viruses, fungi, and parasites) that cause infectious disease are continually trying to avoid and by-pass the drugs that are essential for combatting infection. In the past decades, scientists have countered the loss of potency of antibiotics resulting from resistance to the discovery and development of new ones. Over the past half-century, the strategy of introducing new antibiotics to the market to replace older ones, which lost their effectiveness has proven to be highly successful. Unfortunately, this state of equilibrium has now been shifted. Microbes have developed multiple drug resistance mechanisms, and no new antibiotic has been discovered [2].

Structural modification of existing antimicrobials to which bacteria have developed resistance such as the azoles [3], the non-nucleoside reverse transcriptase inhibitors [4], ß-lactams and quinolones [5] were effective means of extending the lifespan. However, with the selection of chemotherapeutics these days, the researchers are finding alternative ways to find new antimicrobials and do not follow the track of parent structure alterations. One of the recent development is to focus on different target sites to those in current use in finding novel antibiotics [6, 7].

In the past, natural products were also the major promising sources of chemical diversity for starting materials of drug discovery [8], for example, the penicillins, the tetracyclines and the glycopeptides between 1940 and 1955. In almost all therapeutic areas, many natural products or...