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EDITORIAL
published: 21 February 2017
doi: 10.3389/fmicb.2017.00210
Frontiers in Microbiology | www.frontiersin.org 1February 2017 | Volume 8 | Article 210
Edited by:
Fiona Walsh,
Maynooth University, Ireland
Reviewed by:
Jayanta Kumar Patra,
Dongguk University, South Korea
*Correspondence:
Luis C. N. da Silva
luisclaudionsilva@yahoo.com.br
Specialty section:
This article was submitted to
Antimicrobials, Resistance and
Chemotherapy,
a section of the journal
Frontiers in Microbiology
Received: 12 December 2016
Accepted: 30 January 2017
Published: 21 February 2017
Citation:
da Silva LCN, da Silva MV and
Correia MTdS (2017) Editorial: New
Frontiers in the Search of
Antimicrobials Agents from Natural
Products. Front. Microbiol. 8:210.
doi: 10.3389/fmicb.2017.00210
Editorial: New Frontiers in the Search
of Antimicrobials Agents from
Natural Products
Luis C. N. da Silva 1*, Márcia V. da Silva2and Maria T. dos Santos Correia 2
1Programa de pós-graduação em Biologia Parasitária, Universidade Ceuma, São Luís, Brazil, 2Departmento de Bioquímica,
Centro de Biociências, Universidade Federal de Pernambuco, Recife, Brazil
Keywords: antibiotics, antivirulence, immunomodulation, action mechanism, bioactive compounds
Editorial on the Research Topic
New Frontiers in the Search of Antimicrobials Agents from Natural Products
Infectious diseases still one of the major causes of mortality and morbidity worldwide. The
incidences of these infections are higher in communities exposed to inadequate sanitary conditions
(commonly found in developing countries), and hospitalized and immunosuppressed individuals.
This parasitic efficiency of microorganisms is due their high capacity to develop strategies to evade
immune system and provoke host damage through virulence factor expression (Chan et al.; Hassan
et al.; Al Atya et al.). In addition, these pathogens are able to acquire antimicrobial resistance by
either drug-induced selection or drug-mediated mutagenesis (Castro et al.; Marini et al.; Morita
et al.). Both cases result in diminution of antibiotic shelf time and make essential the search of new
active compounds to be used in antimicrobial therapy. Natural products from micro-organisms,
plants, animals, and algae have been proved to be excellent sources of antimicrobial compounds
(Antoraz et al.; Deshmukh et al.; Santos et al.; Carter et al.; Lacerda et al.). The papers published in
this Research Topic have proved this hypothesis as we illustrate bellow.
The production of antibiotics by microorganisms has been recognized for a long time. Several
research groups have isolated new microbial species (bacteria, actinobacteria, fungi) able to
produce new antimicrobial compounds or more productive strains (Antoraz et al.; Deshmukh
et al.). In our Research Topic, active microorganisms were obtained from different niches
since traditional sources—such as soil (Hassan et al.), plant (endophytes) (Santos et al.)—until
unusual environments—such as Antarctic Ocean (Papa et al.), hypersaline habitats (Jose and
Jebakumar), and mud wasp nests (Kumar et al.). Some papers also showed that active bacteria
could be found associated to invertebrate organisms such as marine sponges (Graça et al.; Saurav
et al.) and rhabditid entomopathogenic nematode (Deepa et al.). These microorganisms showed
biotechnological aptitude as they produced compounds able to inhibit the growth of bacteria
(Kumar et al.; de Oliveira et al.) and fungi (Kumar et al.; Kumar et al.).
Some bacteria were also able to inhibit virulence factors such as biofilm formation, toxins and
proteases (Hassan et al.; Papa et al.; Saurav et al.). One example is nisin, a lantibiotic produced by
Lactococcus lactis. Besides its activity against Gram-positive and Gram-negative planktonic cells of
oral bacteria, nisin was able to impair multi-species biofilms (by inhibiting the biofilm formation
or eradicating pre-formed biofilm). At anti-biofilm concentrations, nisin treatment did not result
in toxicity toward human cells relevant to the oral cavity (Shin et al.). In another remarkable
paper, the cis-2-decenoic acid (CDA) signaling network of Pseudomonas aeruginosa was revealed
by microarray analysis. CDA is a signaling molecule involved in quorum-sensing. The authors also
showed that this compound could disperse biofilms of P. aeruginosa alone or when combined with
conventional antibiotics (Rahmani-Badi et al.).
da Silva et al. Natural Products as Antimicrobial Agents
An important effect against mycobacterial persister cells
was shown for boromycin, a macrolide antibiotic produced by
Streptomyces antibioticus. This compound targets mycobacterial
transmembrane ion gradients and displays activity against both
growing and non-growing drug tolerant cells. Its action was not
related to resistance induction (Moreira et al.). Another elegant
paper employed, for the first time, the phenylalanine/tyrosine
ammonia lyase enzyme produced by Rhodotorula glutinis in the
bioconversion of L-tyrosine methyl ester (L-TM) to the methyl
ester of para-hydroxycinnamic acid (p-HCAM), an antibacterial
product (MacDonald et al.). Finally, the improvement of
antibiotic production through optimization of culture conditions
was also demonstrated by a couple of papers (Kumar et al.;
Rajeswari et al.).
Plants derived compounds are also attractive candidates for
bioprospecting programs due their high chemical diversity which
results in the inhibition of a range of microbial pathways
(Santos et al.). Plants have been widely used by traditional
communities due to their supposed medicinal properties. This
popular knowledge has directed a lot of researches aiming to
provide scientific evidence of these actions (Zhang et al.; Bezerra
dos Santos et al.; Tiwari et al.; Saritha et al.; Silva et al., 2016).
In other hand, some plants that are not used in folk medicine
are also source of bioactive compounds. The papers published
in this Research Topic discussed the action of different plant
derived agents such as plant extracts (Saritha et al.; Silva et al.,
2016), essential oils (Islamuddin et al.; Monte et al.; Hyldgaard
et al.; Magi et al.), proteins (Silva and Correia; Patriota et al.),
polyphenols (Stevens et al.; Taleb et al.), and triterpenoids (Wu
et al.). The antimicrobial activity of these plant compounds was
further characterized using alternative infections models such as
Caenorhabditis elegans (Eng and Nathan) and Zebrafish embryo
(Stevens et al.).
Another emergent topic in antimicrobial field is the research
using honey as source of bioactive molecules. Indeed, honey
has been used in traditional medicine to treat infections
(Carter et al.). The multiple therapeutic properties of honey
are due to its chemical diversity (sugars, peptides, proteins,
hydroxymethylfurfural are examples of bioactive compounds)
(Laallam et al.). One of these studies lead to the isolation of
glycoproteins from honey which showed sequence identity with
the Major Royal Jelly Protein 1 (MRJP1) which is composed
by three antimicrobial peptides: Jelleins 1, 2, and 4. These
glycoproteins exhibit a broad spectrum activity against multi-
drug resistant clinical isolates (Brudzynski et al.).
Silva et al. discussed the use of antimicrobial peptides
(AMP) from different sources (including microorganisms,
insects, amphibians, plants, and humans) in the development
of optical and dielectric sensors for microbial detection.
Due the advances in nanotechnology, different nanostructured
platforms containing AMP have been obtained resulting
in biosensors with increased efficiency. These AMP-based
biosensors could be employed for microbial diagnosis and for
ensure the quality of different products such as water, food, and
cosmetic.
Regarding the protozoal infections, the use of peptide from
host insects as drug against Leishmania sp., Plasmodium sp.,
and Trypanosomes was reviewed by Lacerda et al. These authors
also discussed the application of transcriptome analysis to
prospect new peptides from non-host insects. Other paper
demonstrated the leishmanicidal activity of Piper nigrum, a
well-known medicinal plant. The bioactive fractions are able
to induce apoptosis in promastigote forms of Leishmania
donovani. Moreover, these fractions exhibited therapeutic
action against experimental leishmaniasis which was related
to their immunostimulatory potential (targeting Th1 pathway;
Chouhan et al.). Anti-leishmania action was also evaluated
to β-nitrostyrenes, a rare class of reddish brown compounds
with antimicrobial activity which has been isolated from
Streptomyces lavendulaea (2,4-dihydroxy-β-nitrostyrene) and
Indian mangrove plant Sonneratia acids Linn. F (2-nitro-
4-((E)-2-nitrovinyl)phenol). Some β-nitrostyrenes derivative
compounds (synthesized using Henry reaction) were found
to selectively inhibit promastigotes and amastigotes forms of
L. donovani (Shafi et al.).
The antiviral properties of Cameroonian medicinal plants
against hepatitis C virus (HCV) were also evaluated. The plants
were selected based in an ethnobotanical survey which revealed
that several plants from Western region of Cameroon have
been used to treat liver-related disorders. Three plants (Trichilia
dregeana,Detarium microcarpum, and Phragmanthera capitata)
were found as source of anti-HCV compounds and the activity
was related to inhibition of HCV entry without affect viral
replication or secretion (Galani et al.). Other paper showed
the potential use of dryocrassin ABBA against amantadine-
resistant H5N1 avian influenza virus (HPAIV). Dryocrassin
ABBA is a phloroglucinol derivative isolated from Rhizoma
Dryopteridis Crassirhizomatis. This compound increased the
survival rates of HPAIV virus infected mice, decreased lung
index and virus loads. It also exhibited immunomodulatory
action inhibiting pro-inflammatory cytokines (IL-6, TNF-α,
and IFN-γ) and increasing anti-inflammatory cytokines (IL-10
and MCP-1).
Taken together, all these papers illustrate the versatility of
natural products and highlight the importance of developing new
prospection tools to impulse the discovery of new compounds.
These molecules could be used as drug leads and also provide
more insights for target discovery.
AUTHOR CONTRIBUTIONS
All authors listed, have made substantial, direct and intellectual
contribution to the work, and approved it for publication.
ACKNOWLEDGMENTS
The Editors would like to thank all authors that participated
in this Research Topic in “New frontiers in the search
of antimicrobials agents from natural products”. Special
acknowledgment is given to each reviewer (external or editorial
board member), who has contributed and whose valuable
support is fundamental to the success of the journal. We are also
grateful to Conselho Nacional de Desenvolvimento Científico
Frontiers in Microbiology | www.frontiersin.org 2February 2017 | Volume 8 | Article 210
da Silva et al. Natural Products as Antimicrobial Agents
e Tecnológico (CNPq), Coordenação de Aperfeiçoamento de
Pessoal de Nível Superior (CAPES), Fundação de Amparo à
Pesquisa e ao Desenvolvimento Científico e Tecnológico do
Maranhão (FAPEMA), and Fundação de Amparo à Ciência do
Estado de Pernambuco (FACEPE), for the financial support to
the editors.
REFERENCES
Silva, A. P. S. A., Silva, L. C. N., Fonseca, C. S. M., Araújo, J. M., Santos Correia, M.
T., Silva Cavalcanti, M., et al. (2016). Antimicrobial activity and phytochemical
analysis of organic extracts from Cleome spinosa Jaqc. Front. Microbiol. 7:963.
doi: 10.3389/fmicb.2016.00963
Conflict of Interest Statement: The authors declare that the research
was conducted in the absence of any commercial or financial
relationships that could be construed as a potential conflict of
interest.
Copyright © 2017 da Silva, da Silva and Correia. This is an open-access article
distributed under the terms of the Creative Commons Attribution License (CC BY).
The use, distribution or reproduction in other forums is permitted, provided the
original author(s) or licensor are credited and that the original publication in this
journal is cited, in accordance with accepted academic practice. No use, distribution
or reproduction is permitted which does not comply with these terms.
Frontiers in Microbiology | www.frontiersin.org 3February 2017 | Volume 8 | Article 210
