Marine Rare Actinomycetes: A Promising Source of Structurally Diverse and Unique Novel Natural Products.

Subramani Subramani,Sipkema Sipkema

doi:10.3390/md17050249

Subramani Subramani, Sipkema Sipkema

Open Access

https://doi.org/10.3390/md17050249

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Abstract

Rare actinomycetes are prolific in the marine environment; however, knowledge about their diversity, distribution and biochemistry is limited. Marine rare actinomycetes represent a rather untapped source of chemically diverse secondary metabolites and novel bioactive compounds. In this review, we aim to summarize the present knowledge on the isolation, diversity, distribution and natural product discovery of marine rare actinomycetes reported from mid-2013 to 2017. A total of 97 new species, representing 9 novel genera and belonging to 27 families of marine rare actinomycetes have been reported, with the highest numbers of novel isolates from the families Pseudonocardiaceae, Demequinaceae, Micromonosporaceae and Nocardioidaceae. Additionally, this study reviewed 167 new bioactive compounds produced by 58 different rare actinomycete species representing 24 genera. Most of the compounds produced by the marine rare actinomycetes present antibacterial, antifungal, antiparasitic, anticancer or antimalarial activities. The highest numbers of natural products were derived from the genera Nocardiopsis, Micromonospora, Salinispora and Pseudonocardia. Members of the genus Micromonospora were revealed to be the richest source of chemically diverse and unique bioactive natural products.

Highlights

Emerging infectious diseases and multidrug-resistant human pathogens are becoming a major threat to global health [1]
We summarized the novel families, novel genera, and new species of rare actinomycetes from marine habitats including bioactive compounds reported from 2007 to mid-2013 [7]
The goal of this present review is to summarize new species of marine rare actinomycetes, and the bioactive compounds discovered between mid-2013 and 2017 and discuss their chemical diversity and biotechnological potential

Summary

Introduction

Emerging infectious diseases and multidrug-resistant human pathogens are becoming a major threat to global health [1]. Despite the use of large synthetic combinatorial libraries of molecules to develop novel drugs, natural products and microbial metabolites, in particular, are a predominant source of bioactive scaffolds that represent the foundation for the development of life-saving antibiotics [2]. Even the known species have only been explored for bioactivity or for natural product discovery up to a limited extent. Natural resources are virtually unlimited for natural product discovery. The phylum Actinobacteria represents one of the largest phyla among the 30 major phyla currently recognized within the domain Bacteria. There are 6 classes, 18 orders, 14 suborders, 63 families and 374 genera recorded in this phylum until

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