1. Introduction

Plants have been used in traditional medicine for centuries due to the synthesis of several molecules that provide antibacterial and antifungal properties, the majority of which probably evolved as defenses against infection or predation [1]. The medicinal potential of many plants is still largely unexplored. Among the estimated 250,000–500,000 plant species, a relatively small percentage have been investigated phytochemically and the fraction submitted for

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

biological or pharmacological screening is even smaller [2]; approximately 20% of the plant species in the world have been investigated for these properties [3]. In this context, dandelion serves as an interesting species with which to unify decades-old information regarding its biological potential against diverse microorganisms. This review gathers the existing results to advance the search for products that could strengthen the domestication and mass production of this plant.

relevance as part of an Italian program between the University of Ferrara and the University of Naples for screening medicinal plants [20]. Nowadays, this plant is becoming a promising species in the treatment of several bacterial and fungal diseases due to the results of various antimicrobial-related studies. This chapter seeks to elucidate both the traditional uses and current state of Taraxacum in antimicrobial research to determine the potential that this genus has to become an industrial medicinal crop worldwide. Due to the high potential value that could be derived from the use of new technologies and industrial products developed from this type of plant species, the conservation and protection of the crop should be considered and sustainable global production strategies are developed in accordance with assessments of

*Taraxacum* Genus: Potential Antibacterial and Antifungal Activity

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Literature reviews providing information on the antimicrobial aspects of natural products, which had until now only been considered empirical, have been recently scientifically confirmed as a means of countering the increasing reports of pathogenic microorganisms resistant to synthetic antimicrobial agents. Some plant-derived compounds can control microbial growth, either separately or in association with conventional antimicrobials [21]. Currently, numerous studies seek to improve pathogen prevention by combining the application of medicinal herb extracts with an antibiotic or effective antipathogenic pesticide to reduce the

Among the Taraxacum genus, T. officinale is the most frequently reported species, with almost 80% of mentions in documents related to antimicrobial properties (see Table 2), followed by T. mongolicum and T. coreanum, though over 2500 Taraxacum species are currently identified [67]. Other, less studied species include T. platycarpum, T. farinosum, T. ohwianum, and T. phaleratum; however, the relevance of these species is confined to specific areas (mostly in Asia) in which they grow naturally since they are not deliberately cultivated for medicinal benefit. This indicates that the microbial properties of less than 1% of all Taraxacum species discovered have

Taraxacum extracts have been tested on different bacterial and fungal strains affecting humans, animals, and plants to determine its antimicrobial profile, confirm its traditional usage, and expand its known uses. Antimicrobial agents are categorized based on the spectrum of action, namely "narrow" and "broad" spectrum, which indicates whether its use is specific for certain bacterial strains or active on a wider range. Bacterial infections can result in mild to lifethreatening illnesses that require immediate antibiotic intervention. Alternatively, a superficial fungal infection is rarely life-threatening but can have debilitating effects and may spread to other people or become invasive or systemic, resulting in a life-threatening infection. The widespread, and sometimes inappropriate, use of chemical compounds can create antibiotic

ecological, economic, and social factors.

2.2. Bacterial and fungi strains tested

2. Antimicrobial properties of the Taraxacum genus

active synthetic ingredient and resistant pathogenic strains.

2.1. Taraxacum species tested for antimicrobial properties

been studied, revealing the enormous research potential of this genus.

The Taraxacum spp. commonly called dandelion is an herbaceous perennial plant of the Asteraceae (Compositae) family. This common weed is found worldwide, though originally introduced from Eurasia, and can be found growing in parks, gardens, pastures, orchards, roadsides, vegetable gardens, and among agricultural and horticultural crops [4]. Primarily used as food, the role of Taraxacum in traditional medicine was mentioned during ancient times by the Greek physician Dioscorides in the first century and during the renaissance by monks in Cyprus [5]. This plant has been used to treat cystitis, liver and gastric ailments, hepatic and renal detoxification, diabetes, as an anti-inflammatory and anticarcinogenic agent, and, to a lesser extent, as an antimicrobial and antiviral agent, as described in several reviews [6, 7]. Ethnopharmacologically, its use as an antimicrobial agent has been known worldwide among varying cultures, though it has always been administered as a cataplasm (poultice) or infusion. The traditional antimicrobial uses of Taraxacum worldwide are displayed in Table 1.

Asia and Europe have an important historical background regarding the traditional uses of Taraxacum, primarily T. officinale, T. mongolicum, and T. coreanum. This traditional knowledge has been the principal reason for studying the potential uses and crop requirements of Taraxacum; studies in America remain scarce [18]. Due to the unscientific approach often present in oral traditions, uncertainty surrounds whether Taraxacum use effectively treats microbial infection or, instead, treats only the symptoms. Therefore, scientific research is extremely important in avoiding misinterpretation and myths regarding Taraxacum or any other plant.

The first antibacterial scientific study for Taraxacum was reported a mere 35 years ago [19]. More than a decade later, studies related to Taraxacum antimicrobial activity gained significant


Table 1. Ethnopharmacological information of Taraxacum genus used as an antimicrobial traditional medicine.

relevance as part of an Italian program between the University of Ferrara and the University of Naples for screening medicinal plants [20]. Nowadays, this plant is becoming a promising species in the treatment of several bacterial and fungal diseases due to the results of various antimicrobial-related studies. This chapter seeks to elucidate both the traditional uses and current state of Taraxacum in antimicrobial research to determine the potential that this genus has to become an industrial medicinal crop worldwide. Due to the high potential value that could be derived from the use of new technologies and industrial products developed from this type of plant species, the conservation and protection of the crop should be considered and sustainable global production strategies are developed in accordance with assessments of ecological, economic, and social factors.
