metabolites including alkaloids, phenolics, terpenoids and saponins. These metabolites

provide them a defense mechanism against biological and non-biological stress factors.

On the other hand, the same metabolites have proved to be effective against different

dreadful human diseases. The efficacy of such metabolites ranges from antimicrobial to

anticancerous effects. Bioactivity-guided characterization is one of the useful strategies

that have been employed to identify, purify and characterize active components. These

bioactive components have proved useful in future drug discovery. Elicitors are defined

as signaling metabolites with the ability to induce biochemical and physiological

processes in plants resulting in the activation of plants defense mechanisms. Elicitation

is a useful tool as it leads to the generation of stress conditions and hence the

accumulation of bioactive secondary metabolites in plants. Various strategies have

been adopted to enhance the production of bioactive secondary metabolites including

plant cell and tissue culture and use of signaling metabolites. Nowadays, nano-elicitors

have emerged as an effective tool to enhance the production of pharmacologically

important compounds. Various classes of nanoparticles (NPs) have been reported to be

utilized as nano-elicitors like metallic NPs, metallic oxide NPs and carbon nanotubes

with positive effects on phytochemical profile. The possible mechanism of

nanomaterials as elicitors is the interaction with plant genomes by increasing the

expression level of genes involved in the biosynthesis of active metabolites. Despite

triggering biosynthetic potential of plants, certain negative effects have been observed

in plants’ primary metabolism like lower chlorophyll content, a decrease in cell

viability, a decline in sugar content and suppressed seed germination. Thus, there is a

need to develop biocompatible nanoparticles for use as nanoelicitors in plants to avoid

the negative impacts of the used entities.