Amino acid–derived defense metabolites from plants: A potential source to facilitate novel antimicrobial development

Abstract

For millennia, humanity has relied on plants for its medicines, and modern pharmacology continues to reexamine and mine plant metabolites for novel compounds and to guide improvements in biological activity, bioavailability, and chemical stability. The critical problem of antibiotic resistance and increasing exposure to viral and parasitic diseases has spurred renewed interest into drug treatments for infectious diseases. In this context, an urgent revival of natural product discovery is globally underway with special attention directed toward the numerous and chemically diverse plant defensive compounds such as phytoalexins and phytoanticipins that combat herbivores, microbial pathogens, or competing plants. Moreover, advancements in “ omics ,” chemistry, and heterologous expression systems have facilitated the purification and characterization of plant metabolites and the identification of possible therapeutic targets. In this review, we describe several important amino acid–derived classes of plant defensive compounds, including antimicrobial peptides ( e.g. , defensins, thionins, and knottins), alkaloids, nonproteogenic amino acids, and phenylpropanoids as potential drug leads, examining their mechanisms of action, therapeutic targets, and structure–function relationships. Given their potent antibacterial, antifungal, antiparasitic, and antiviral properties, which can be superior to existing drugs, phytoalexins and phytoanticipins are an excellent resource to facilitate the rational design and development of antimicrobial drugs.

New Insight into Aspartate Metabolic Pathways in Populus: Linking the Root Responsive Isoenzymes with Amino Acid Biosynthesis during Incompatible Interactions of Fusarium solani

“…Four AlaATs exist in Arabidopsis , divided into AtAlaATs and AtGGTs . A novel enzyme gene (At3g08860) was recently endowed with AlaAT activity [ 72 ]. Arabidopsis AlaAT1 knockout mutant accumulated higher levels of Ala upon hypoxia, and less efficiency in utilization of exogenous Ala, indicating the importance of AlaAT in low-oxygen stress recovery and Ala metabolism [ 73 ].…”

Plant-Derived Antimicrobial Peptides as Potential Antiviral Agents in Systemic Viral Infections

“…Parthasarathy reported the anti-IBV activity of one alstotide, As1, which functions by blocking the spike protein and thus inhibiting the fusion of the virus with the host cell during the viral replication cycle. The same knottin may also interact with the IBV membrane (M) protein and consequently present a multitarget activity [ 68 ].…”

Amino Acid Based Antimicrobial Agents – Synthesis and Properties

“…Mimosine (Figure 11 ), known also as leucenol, is a toxic non‐protein amino acid produced by seeds, leaves and roots of several Fabeceae, including Mimosa pudica . [210] This compound is well known for its mammalian toxicity, which is due to the inhibition of DNA replication. [211] An antifungal spectrum of mimosine comprises human pathogenic dermatophytic fungi but does not cover human pathogenic yeasts.…”