الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Nature produces an amazing variety and number of products. The story of bioactive compounds started more than one hundred years ago. They are defined as the chemical compounds isolated from living organisms such as microorganisms, plants and animals. These natural products may be derived from the primary or secondary metabolites of these living organisms (Bérdy, 2005; Barka et al., 2016; Abdel-Razek et al., 2020). The chemistry of natural bioactive molecules is related to the isolation, biosynthesis and structure that lead to new drugs. Due to their chemical diversity and various activities against pathogens, they have important roles in the field of researches related to agriculture, aquaculture and pharmaceutical industry (Fig. 2.1) (Barka et al., 2016; Rajaram et al., 2020; Betina et al., 1994).Microorganisms have been reported to produce around 23,000 bioactive secondary metabolites and over ten thousands of these compounds are produced by actinomycetes, representing 45% of all bioactive microbial metabolites discovered (Shin, 2013; Hu et al., 2015). Among actinomycetes, around 7600 compounds are produced by Streptomyces species (Antunes et al., 2014; Sharma, 2014). In the Marinlit database (2015) 289 secondary metabolites from the marine-members of genus Streptomyces are recorded. These substances cover a wide variety of chemical structures, including macrolides, peptides, indoles, lactones, quinones and terpenes (Han et al., 2012). These bioactive compounds show an extensive range of industrially useful applications, as well as they are used to medicate many pathogenic diseases (Table 2.1) (Bhatnagar &Kim, 2010). Many species of actinomycetes that have not yet been isolated under laboratory conditions are expected to occur in these different habitats, and they can be a source of new drugs with novel chemistry and promising potential (Sharma et al., 2013; Abd-Elnaby et al., 2016-a).