Fighting Multidrug Resistance with Herbal Extracts, Essential Oils and their Components offers scientists a single source aimed at fighting specific multidrug-resistant (MDR) microorganisms such as bacteria, protozoans, viruses and fungi using natural products. This essential reference discusses herbal extracts and essential oils used or under investigation to treat MDR infections, as well as those containing antimicrobial activity that could be of potential interest in future studies against MDR microorganisms. The need to combat multidrug-resistant microorganisms is an urgent one and this book provides important coverage of mechanism of action, the advantages and disadvantages of using herbal extracts, essential oils and their components and more to aid researchers in effective antimicrobial drug discovery Addresses the need to develop safe and effective approaches to coping with resistance to all classes of antimicrobial drugs Provides readers with current evidence-based content aimed at using herbal extracts and essential oils in antimicrobial drug development Includes chapters devoted to the activity of herbal products against herpes, AIDS, tuberculosis, drug-resistant cancer cells and more

Aromatic and medicinal plants, through their secondary metabolism, provide a complex mixture of volatile molecules known as essential oils. These volatile molecules exert antibacterial activity that has been used in folk medicine for centuries. During the last few decades, the emergence of antibacterial resistance has forced us to search for new and efficient antimicrobial agents. The significant number of studies on the use of essential oils and their components against multidrug-resistant bacteria, such as Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, Mycobacterium tuberculosis, and Pseudomonas aeruginosa show the exceptional potential of these natural products to curb the development of antibacterial resistance. Moreover, the use of essential oils and their components in combination with antibiotics may increase bacterial susceptibility, thus limiting resistance.

In today’s world, multidrug resistance appears to be one of the major health problems; however, screening, discovering and presenting novel effectual phytochemicals from medicinal plants have provided a promising outlook. Phytomedicines have been used for treating diseases and infections since time immemorial, but identifying new phytochemicals and effectual treatment strategies are essential in the fight against multidrug-resistant bacteria. Currently, isolated compounds such as α-mangostin, carnosic acid, epigallocatechin gallate, linalool, myricetin, novoimanin, α-terpineol, and totarol, have exhibited synergistic activity with antibiotics against resistant bacteria. This chapter presents information on multidrug-resistant Gram-negative bacteria and the use of herbal extracts against them.

Many bacterial diseases affect animals, causing important economic losses in livestock. Subtherapeutic antibiotic use in production animals as antibiotic growth promoters has been implicated as a causative factor in the development of resistance of bacterial pathogens toward several classes of antimicrobials, some of which are used therapeutically in humans. This has led to the banning of antibiotic growth promoters by the European Union, and such a precedent may be followed in other countries. Alternatives to antibiotic growth promoters are necessary to enable the production of animal protein to keep pace with the expanding world population. One approach is to use plant extracts or essential oils as supplements to provide beneficial effects, including direct antibacterial activity and stimulation of the immune system, or enhancement of ruminal digestion. The risk of resistance developing to a combination of phytochemicals is lower than the risk of resistance against a single antibiotic, and synergistic effects of plant constituents may contribute to the overall activity of the preparation.

Antibiotics are antimicrobial agents that are used to treat infectious diseases. The outbreak of pathogenic antibiotic-resistant strains illustrates our urgent need to search for new alternative sources of treatment. Hence, an attempt has been made in this review to list some plant extracts, essential/volatile oils, and their antimicrobial activity against different microorganisms using different methods, as well as synergistic effects (plant extract-plant extract, plant extract-essential oils, plant extract-conventional antibiotics, phytochemical-antibiotics, and essential oil-essential oil). Plant products and their active constituents are useful in the treatment of infectious diseases caused by multidrug-resistant microbes, food borne diseases caused by food spoiling microbes, and oral pathogens. Products derived from plants have the potential to control microbial growth in diverse situations, and specifically in the treatment of disease. The various aspects of this review may be helpful for the food, cosmetic, and pharmaceutical industries.

Natural products have played a pivotal role in antibiotic drug discovery, with most anti-infective drugs being derived from natural products or natural product leads. However, the rapid onset of resistance to most anti-infective drugs considerably diminishes their effectiveness and requires a constant supply of new drugs for the effective treatment of infections. Infectious diseases account for a third of all deaths worldwide. The spread of multidrug-resistant strains of bacteria makes it necessary to identify new classes of antibacterials and compounds that inhibit these resistance mechanisms. Numerous members of the Asteraceae family are important as cut flowers and ornamental crops, as well as being medicinal and aromatic plants, many of which produce essential oils used in folk and modern medicine and in the cosmetics and pharmaceutical industries. Essential oils generally have a broad spectrum of bioactivity, owing to the presence of several active ingredients (e.g., terpenes and phenol-derived aromatic and aliphatic components) that have various modes of action. Extensive studies of the chemical components of Asteraceae species have led to the identification of many substances, including essentials oils, with interesting antibacterial activity. This review summarizes some of the main reports on the chemistry and antibacterial activity of Asteraceae essential oils in the recent literature (2005 to May 2012).

Methicillin-resistant Staphylococcus aureus (MRSA) is currently one of the most common causes of serious infections, in both hospital and community environments. This type of resistance was discovered in the 1960s, and now (50 years later) it has not been possible to develop an effective therapy to fight against it. This chapter compiles the results of several studies demonstrating the activity (mainly in vitro) of various extracts, essential oils, and plant-derived molecules that can act alone or in combination against MRSA. In addition, natural alternatives (other than from plants) being studied for the same purpose are described. Finally, the important role of phytotherapy in the development of new therapies against multidrug-resistant bacteria such as MRSA is emphasized.