Comprehensive review of antimicrobial activities of plant flavonoids

Abstract

Flavonoids are one of the largest classes of small molecular secondary metabolites produced in different parts of the plant. They display a wide range of pharmacological and beneficial health effects for humans, which include, among others, antioxidative activity, free radical scavenging capacity, coronary heart disease prevention and antiatherosclerotic, hepatoprotective, anti-inflammatory, and anticancer activities. Hence, flavonoids are gaining high attention from the pharmaceutical and healthcare industries. Notably, plants synthesize flavonoids in response to microbial infection, and these compounds have been found to be a potent antimicrobial agent against a wide range of pathogenic microorganisms in vitro. Antimicrobial action of flavonoids results from their various biological activities, which may not seem very specific at first. There are, however, promising antibacterial flavonoids that are able not only to selectively target bacterial cells, but also to inhibit virulence factors, as well as other forms of microbial threats, e.g. biofilm formation. Moreover, some plant flavonoids manifest ability to reverse the antibiotic resistance and enhance action of the current antibiotic drugs. Hence, the development and application of flavonoid-based drugs could be a promising approach for antibiotic-resistant infections. This review aims to improve our understanding of the biological and molecular roles of plant flavonoids, focusing mostly on their antimicrobial activities.

Rhizosphere modelling reveals spatiotemporal distribution of daidzein shaping soybean rhizosphere bacterial community

“…Daidzein treatment reduced the α-diversity of bacterial communities, and observed operational taxonomic units were markedly reduced at daidzein concentrations greater than 250 nmol g −1 of soil ( Figure S5), suggesting that daidzein affected the assemblage of the bacterial community. Daidzein possesses antimicrobial activity (Gorniak, Bartoszewski, & Kroliczewski, 2019) and serves as a carbon source for a particular group of bacteria that metabolize daidzein. The reduction of α-diversity is a typical change observed in the bacterial communities in the rhizosphere (Duran et al, 2018).…”

Naringenin as an antibacterial reagent controlling of biofilm formation and fatty acid metabolism in MRSA

“…The overuse of antibiotics for long term had led to the findings of new anti-bacterial agent such as plant derived flavonoids (21). To be more specific, flavonoids are safe as they originated from natural origin and they can be modified to have more efficacy (11). Flavonoids are secondary metabolites which are naturally produced by plant or fungus and they are acting generally as pigment, quorum sensing molecules, antibiotics to other competitive microorganisms (22).…”

“…For example, they can block respiratory chain, fatty acid synthesis, gyrase activity, quorum sensing molecules and increase membrane permeability etc. (11). However, its functional mechanism on antibacterial activities are not well known.…”

“…Since they derived from the natural origins, they seem safer to consumers than the chemically synthesized drugs. Also, they have advantages over antibiotics that they have multiple activities acting on the cells, so it is hard for bacteria to develop resistance to them (11). Thus, many approaches have been carried out to seek natural origin flavonoids having anti-bacterial effect and develop to make them have stronger efficacy (12).…”

“…For example, catechins can disrupt the bacterial membrane by interacting with membrane and inhibiting enzymes (13). Isovitexin (apigenin-6-glycoside 14), epicatechin, and 5, 7, 5’-trihydroxyflavanol were active against Staphylococcus aureus having anti-biofilm activity (11). Naringenin, quercetin, sinensetin and apigenin have been shown as inhibitors of autoinducer-mediated cell-cell signaling (14).…”