Antimicrobial Properties of Plant-Derived Flavonoids

Flavonoids constitute a large family of plant secondary metabolites that display potent antimicrobial activities against bacteria, fungi and, to a lesser extent, viruses. Their efficacy arises from multiple mechanisms, including disruption of microbial membranes, alteration of membrane permeability, inhibition of nucleic acid and protein synthesis, interference with energy metabolism and suppression of virulence determinants such as biofilm formation and quorum sensing. Structural diversity within flavonoid subclasses (flavones, flavonols, flavanones and their glycosides) underpins a broad spectrum of activity, with specific substitution patterns—hydroxylation, prenylation or glycosylation—modulating potency and selectivity. Beyond direct antimicrobial action, many flavonoids synergise with conventional antibiotics, reversing resistance phenotypes or lowering effective doses. Their low toxicity to mammalian cells, coupled with potential applications in food preservation, medical device coatings and adjunctive therapies, highlights their global significance in addressing antimicrobial resistance.

Research from Nature Portfolio

A recent investigation established robust regression models linking flavonoid lipophilicity (logP and logD values) to their minimum inhibitory concentrations against Gram-positive bacteria. By analysing over sixty compounds, the study demonstrated that an optimal range of lipophilicity predicts potent activity, with the most active flavonoids exhibiting logP values between 2·6 and 10·2 μM in predicted MIC terms. Validation on an independent dataset confirmed that membrane disruption constitutes the primary mechanism of action, likely involving perturbation of phospholipid bilayers and inhibition of respiratory chain components. These findings provide a predictive framework for rapid in silico screening of novel flavonoid candidates.

Antimicrobial Properties of Plant-Derived Flavonoids publication trend

The graph below shows the total number of articles in antimicrobial properties of plant-derived flavonoids across all publications each year (not limited to Nature Index journals).

Technical terms

Flavonoids: A diverse class of plant secondary metabolites characterised by two aromatic rings linked via a three-carbon bridge, exhibiting a range of biological activities including antimicrobial effects.

Minimum inhibitory concentration (MIC): The lowest concentration of an antimicrobial agent required to prevent visible growth of a microorganism under defined laboratory conditions.

Lipophilicity: A measure of a compound’s affinity for lipid versus aqueous phases, commonly expressed as the partition coefficient (logP), which influences membrane interaction and cellular uptake.

Biofilm: A structured community of microbial cells enclosed in a self-produced extracellular matrix and adhered to a surface, often exhibiting enhanced tolerance to antimicrobial agents.

References

1. Comprehensive review of antimicrobial activities of plant flavonoids. Phytochemistry Reviews (2018).
2. Antibacterial activity and mechanism of plant flavonoids to gram-positive bacteria predicted from their lipophilicities. Scientific Reports (2021).
3. Interaction of selected alkoxy naringenin oximes with model and bacterial membranes. Biomedicine & Pharmacotherapy (2024).
4. Antimicrobial Activity of Quercetin: An Approach to Its Mechanistic Principle. Molecules (2022).
5. Antibacterial Effects of Flavonoids and Their Structure-Activity Relationship Study: A Comparative Interpretation. Molecules (2022).