Research Progress on Antibacterial Activities and Mechanisms of Natural Alkaloids: A Review

Abstract

Alkaloids are nitrogen-containing heterocyclic compounds typically isolated from plants. They represent one of the most important types of natural products because of their large number and structural diversity and complexity. Based on their chemical core structures, alkaloids are classified as isoquinolines, quinolines, indoles, piperidine alkaloids, etc. In-depth analyses of alkaloids have revealed their antibacterial activities. To date, due to the widespread use of antibiotics, the problem of drug-resistant bacterial infections has been gradually increasing, which severely affects the clinical efficacy of antibacterial therapies and patient safety. Therefore, significant research efforts are focused on alkaloids because they represent a potentially new type of natural antibiotic with a wide antibacterial spectrum, rare adverse reactions, and a low tendency to produce drug resistance. Their main antibacterial mechanisms include inhibition of bacterial cell wall synthesis, change in cell membrane permeability, inhibition of bacterial metabolism, and inhibition of nucleic acid and protein synthesis. This article reviews recent reports about the chemical structures and the antibacterial activities and mechanisms of alkaloids. The purpose is to solve the problem of bacterial resistance and to provide a certain theoretical basis and research ideas for the development of new antibacterial drugs.

In vitro activity of honey, total alkaloids of Sophora alopecuroides and matrine alone and in combination with antibiotics against multidrug-resistant Pseudomonas aeruginosa isolates

“…Natural phenolic compounds, including curcumin and rosmarinic acid with antibiofilm and anti-QS properties have been described (Rasamiravaka et al 2015). Plants contain antibiofilm and anti-efflux pump compounds, including alkaloids (Rasamiravaka et al 2015;Yan et al 2021). Alkaloids are potentially active against various bacterial strains, including drug-resistant ones (Yan et al 2021).…”

Antibacterial Activity and Multi-Targeting Mechanism of Dehydrocorydaline From Corydalis turtschaninovii Bess. Against Listeria monocytogenes

“…Since dehydrocorydaline was a major component with the strongest antibacterial activity among the C. turtschaninovii constituents, it was used to further study its potential antibacterial mechanisms of action against L. monocytogenes . Isoquinoline alkaloids have been studied for their antibacterial mechanisms with respect to their distinctive chemical structures such as inhibition of bacterial nucleic acid synthesis and metabolism, interference with cell membrane transporters, suppression of cell division, and disruption of cell membrane, leading to bacterial cell lysis ( Cushnie et al, 2014 ; Yan et al, 2021 ). These studies agree with our results, indicating that L. monocytogenes cells treated with dehydrocorydaline showed morphological and intracellular structural changes such as disappearance of cell walls, membrane destruction, and leakage of intracellular components in TEM observation ( Figure 2 ).…”

Phytochemicals: A Promising Weapon in the Arsenal against Antibiotic-Resistant Bacteria

“…Their antibacterial activities have been proven, and many studies have reported that they can play a significant role in treating infectious diseases. Their mechanism of action might be due to the enzymatic alterations affecting physiological processes, including inhibition of DNA synthesis and repair mechanisms by intercalating nucleic acids [ 9 , 56 , 57 ]. Isoquinolines, aporphines, quinolones, and phenanthrenes are the most critical alkaloid groups with suitable antibacterial activities [ 35 ].…”