sources or methods that can significantly affect these infections (Swamy and
Rudramurthy 2016; Anand et al. 2019; Kirubakari et al. 2019). Plant-derived
bioactives are known to be relatively safer compared to the presently available
antibiotic agents. Further, phytocompounds exert numerous tonic advantages linked
with their extraordinary effectiveness. Various plant metabolites have demonstrated
synergistic bioactivity when combined with antibiotic agents against several
multi-drug resistant pathogenic microbes. These plant metabolites comprise phenolics, flavonoids, alkaloids, tannins, terpenoids, and many more (Arumugam et al.
2016; Mohanty et al. 2017; Shin et al. 2018; Kirubakari et al. 2019).
In view of these aspects, the discovery of new active substances from natural
sources is the most priority to researchers, considering several advantages. The
pharmacological potential of medicinal plants occurring in the Tropical region has
attracted to develop novel antimicrobials (Calixto 2019). Further, side effects
caused by classical antibiotics have forced scientists to work toward exploring
novel antimicrobial agents to overcome these hitches. Phytoconstituents have
shown to have prospective antimicrobial properties against both sensitive and
resistant pathogenic microbes by exerting diverse mode of action. In this chapter,
the potential of tropical plant species with antibacterial and antifungal activities is
reviewed in detail.
7.2 Target for Antimicrobial Agents and Resistance
Mechanisms
Microbial infections are affecting the lives of several thousands of populaces around
the globe, and are accounted for a major cause of human deaths. Nearly 17% of
total deaths in the year 2013 were because of microbial infections. Further,
microbes are evolving toward resistance to existing antimicrobials, making the
present way of treating pathogens less effective. In recent times, clinically pathogenic bacteria and fungi are being classified on the basis of microbial resistance to
either a single or multi-drug. Majorly, microbial resistance is due to many reasons,
including overdose, misuse, and continuous use of antibiotics (Swamy and
Rudramurthy 2016; Rudramurthy et al. 2016; Khameneh et al. 2019). On the other
hand, bacterial resistance has become an increasing health problem with great
impact on the pharmaceutical industry, as many antibiotics have become resistant.
More recently, different approaches are being recommended to overcome the
multi-drug-resistance mechanisms by pathogenic microbes. One such endorsed
approach is the combination therapy, involving two or more molecules with the
weakened antibiotics (Inui et al. 2007; Kirubakari et al. 2019). These molecules can
be other than antibiotic drugs having antibacterial potentials, for example, phytochemicals. Particularly, these molecules function either individually or together
with antibiotic drugs to improve the antimicrobial property, and thus can be
very effective against wide-ranging bacterial pathogens (Khameneh et al. 2019).
7 Antibacterial and Antifungal Plant Metabolites …
265
Rudramurthy 2016; Anand et al. 2019; Kirubakari et al. 2019). Plant-derived
bioactives are known to be relatively safer compared to the presently available
antibiotic agents. Further, phytocompounds exert numerous tonic advantages linked
with their extraordinary effectiveness. Various plant metabolites have demonstrated
synergistic bioactivity when combined with antibiotic agents against several
multi-drug resistant pathogenic microbes. These plant metabolites comprise phenolics, flavonoids, alkaloids, tannins, terpenoids, and many more (Arumugam et al.
2016; Mohanty et al. 2017; Shin et al. 2018; Kirubakari et al. 2019).
In view of these aspects, the discovery of new active substances from natural
sources is the most priority to researchers, considering several advantages. The
pharmacological potential of medicinal plants occurring in the Tropical region has
attracted to develop novel antimicrobials (Calixto 2019). Further, side effects
caused by classical antibiotics have forced scientists to work toward exploring
novel antimicrobial agents to overcome these hitches. Phytoconstituents have
shown to have prospective antimicrobial properties against both sensitive and
resistant pathogenic microbes by exerting diverse mode of action. In this chapter,
the potential of tropical plant species with antibacterial and antifungal activities is
reviewed in detail.
7.2 Target for Antimicrobial Agents and Resistance
Mechanisms
Microbial infections are affecting the lives of several thousands of populaces around
the globe, and are accounted for a major cause of human deaths. Nearly 17% of
total deaths in the year 2013 were because of microbial infections. Further,
microbes are evolving toward resistance to existing antimicrobials, making the
present way of treating pathogens less effective. In recent times, clinically pathogenic bacteria and fungi are being classified on the basis of microbial resistance to
either a single or multi-drug. Majorly, microbial resistance is due to many reasons,
including overdose, misuse, and continuous use of antibiotics (Swamy and
Rudramurthy 2016; Rudramurthy et al. 2016; Khameneh et al. 2019). On the other
hand, bacterial resistance has become an increasing health problem with great
impact on the pharmaceutical industry, as many antibiotics have become resistant.
More recently, different approaches are being recommended to overcome the
multi-drug-resistance mechanisms by pathogenic microbes. One such endorsed
approach is the combination therapy, involving two or more molecules with the
weakened antibiotics (Inui et al. 2007; Kirubakari et al. 2019). These molecules can
be other than antibiotic drugs having antibacterial potentials, for example, phytochemicals. Particularly, these molecules function either individually or together
with antibiotic drugs to improve the antimicrobial property, and thus can be
very effective against wide-ranging bacterial pathogens (Khameneh et al. 2019).
7 Antibacterial and Antifungal Plant Metabolites …
265