promising resource, although infrequent in clinical practice, but it has already
proven to be very effective in antibacterial action (Gwynne and Gallagher 2018). It
is characterized by producing an absolutely safe irradiation power, consumes little
energy, extremely long-life span, good power, and low intensity. Macedo da Silva
et al. (2020) reported antibiotic-modulating activities of the essential oils
of Eugenia brasiliensis Lam and Piper mosenii C. DC singly or in association with
blue LED (Light-emitting diode) light. They concluded that the association of
aminoglycosides with the blue LED light and essential oils represents an effective
modulatory potential against resistant bacteria such as multi-resistant strains
of Escherichia coli and Staphylococcus aureus. Piper aduncum essential oil was
evaluated in a modulatory experiment associated with blue LED light. The combination of volatile oil with antibiotics showed synergistic effect against S. aureus
and E. coli which was potentiated in the presence of blue LED. The results obtained
in this study showed that the essential oil obtained from Piper aduncum interferes with the action of antibiotics against bacteria exposed to blue LED (Barbosa
et al. 2018).
7.3 Tropical Plants with Relevant Antibacterial Activities
Due to increased bacterial resistance to multiple drugs, antimicrobials arise to
concern and the search for new alternatives therapeutic plants, with medicinal
plants representing an important source to obtain these medicines. The antimicrobial activity of extracts and oils essential of medicinal plants has been proven in
several studies conducted in countries that have a diversified flora (Lautié et al.
2020). In South America, with a wide variety of medicinal plants, research showing
that these may be sources of antimicrobial substances has been frequently reported
in recent years (Spézia et al. 2020). According to Michelin et al. (2005), plant
antibiotics have a chemical structure that differs from that of antibiotics derived
from microorganisms, and may regulate the intermediate metabolism of pathogens,
activating or by blocking reactions and enzymatic synthesis or even changing the
structure of membranes. However, since the advent of antibiotics, the use of plant
derivatives as antimicrobials has been little explored (Cowan, 1999).
The acquisition of resistance to antimicrobials is a phenomenon genetic, related
to alteration of genes contained in micro-organisms, which codify different biochemical mechanisms that impede the action of drugs, These mechanisms of action
can be interference with cell wall synthesis; inhibiting protein synthesis; interfering
with nucleic acid synthesis; decreasing permeability to the antimicrobial agent; and
destructing the structure of the cell membrane (Tenover 2006). Bacterial resistance
can arise by acquisition of mutations or by acquisition of genetic material from
other bacteria. Genes encoding proteins involved in resistance mechanisms can be
located on the chromosome or on extra-chromosomal elements, such as plasmids
and transposons, which move easily from one strain to another, from one species
to another, or even from one genus to another (Sultan et al. 2017). Despite the
7 Antibacterial and Antifungal Plant Metabolites …
269
proven to be very effective in antibacterial action (Gwynne and Gallagher 2018). It
is characterized by producing an absolutely safe irradiation power, consumes little
energy, extremely long-life span, good power, and low intensity. Macedo da Silva
et al. (2020) reported antibiotic-modulating activities of the essential oils
of Eugenia brasiliensis Lam and Piper mosenii C. DC singly or in association with
blue LED (Light-emitting diode) light. They concluded that the association of
aminoglycosides with the blue LED light and essential oils represents an effective
modulatory potential against resistant bacteria such as multi-resistant strains
of Escherichia coli and Staphylococcus aureus. Piper aduncum essential oil was
evaluated in a modulatory experiment associated with blue LED light. The combination of volatile oil with antibiotics showed synergistic effect against S. aureus
and E. coli which was potentiated in the presence of blue LED. The results obtained
in this study showed that the essential oil obtained from Piper aduncum interferes with the action of antibiotics against bacteria exposed to blue LED (Barbosa
et al. 2018).
7.3 Tropical Plants with Relevant Antibacterial Activities
Due to increased bacterial resistance to multiple drugs, antimicrobials arise to
concern and the search for new alternatives therapeutic plants, with medicinal
plants representing an important source to obtain these medicines. The antimicrobial activity of extracts and oils essential of medicinal plants has been proven in
several studies conducted in countries that have a diversified flora (Lautié et al.
2020). In South America, with a wide variety of medicinal plants, research showing
that these may be sources of antimicrobial substances has been frequently reported
in recent years (Spézia et al. 2020). According to Michelin et al. (2005), plant
antibiotics have a chemical structure that differs from that of antibiotics derived
from microorganisms, and may regulate the intermediate metabolism of pathogens,
activating or by blocking reactions and enzymatic synthesis or even changing the
structure of membranes. However, since the advent of antibiotics, the use of plant
derivatives as antimicrobials has been little explored (Cowan, 1999).
The acquisition of resistance to antimicrobials is a phenomenon genetic, related
to alteration of genes contained in micro-organisms, which codify different biochemical mechanisms that impede the action of drugs, These mechanisms of action
can be interference with cell wall synthesis; inhibiting protein synthesis; interfering
with nucleic acid synthesis; decreasing permeability to the antimicrobial agent; and
destructing the structure of the cell membrane (Tenover 2006). Bacterial resistance
can arise by acquisition of mutations or by acquisition of genetic material from
other bacteria. Genes encoding proteins involved in resistance mechanisms can be
located on the chromosome or on extra-chromosomal elements, such as plasmids
and transposons, which move easily from one strain to another, from one species
to another, or even from one genus to another (Sultan et al. 2017). Despite the
7 Antibacterial and Antifungal Plant Metabolites …
269