Article

Antimicrobial activity of flavonoids. Int J Antimicrob Agents

School of Pharmacy, The Robert Gordon University, Schoolhill, Aberdeen AB10 1FR, UK
International Journal of Antimicrobial Agents (Impact Factor: 4.26). 12/2005; 26(5):343-56. DOI: 10.1016/j.ijantimicag.2005.09.002
Source: PubMed

ABSTRACT Flavonoids are ubiquitous in photosynthesising cells and are commonly found in fruit, vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. For centuries, preparations containing these compounds as the principal physiologically active constituents have been used to treat human diseases. Increasingly, this class of natural products is becoming the subject of anti-infective research, and many groups have isolated and identified the structures of flavonoids possessing antifungal, antiviral and antibacterial activity. Moreover, several groups have demonstrated synergy between active flavonoids as well as between flavonoids and existing chemotherapeutics. Reports of activity in the field of antibacterial flavonoid research are widely conflicting, probably owing to inter- and intra-assay variation in susceptibility testing. However, several high-quality investigations have examined the relationship between flavonoid structure and antibacterial activity and these are in close agreement. In addition, numerous research groups have sought to elucidate the antibacterial mechanisms of action of selected flavonoids. The activity of quercetin, for example, has been at least partially attributed to inhibition of DNA gyrase. It has also been proposed that sophoraflavone G and (-)-epigallocatechin gallate inhibit cytoplasmic membrane function, and that licochalcones A and C inhibit energy metabolism. Other flavonoids whose mechanisms of action have been investigated include robinetin, myricetin, apigenin, rutin, galangin, 2,4,2'-trihydroxy-5'-methylchalcone and lonchocarpol A. These compounds represent novel leads, and future studies may allow the development of a pharmacologically acceptable antimicrobial agent or class of agents.

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    • "Their chemical arrangements differ in the hydroxylation, methoxylation, prenylation and glycosylation degrees and patterns (Dai & Mumper, 2010). Cushnie and Lamb (2005, 2011) reviewed the most important aspects of antimicrobial flavonoids. Therefore, in this review we will describe only prenylated flavonoids, with a more specific approach. "
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    ABSTRACT: Phytoalexins and phytoanticipins are plant defence compounds that generally have antimicrobial properties; they include phenolic compounds, glucosinolates, cyanogenic glycosides, oxylipins and al-kaloids, among others. These compounds are highly concentrated in food processing by-products, including peels, seeds, bark, and cereal bran, from which they can be recovered and, excluding those that are toxic, used as plant extracts for food preservation. This would benefit the food industry by generating " clean label " food products, and contribute to mitigate waste disposal problems. The present review describes the occurrence of phytoalexins and phytoanticipins, their enzymatic products, properties , and potential applications as food preservatives.
    International Journal of Food Science & Technology 11/2015; 46:49-59. DOI:10.1016/j.tifs.2015.07.013 · 1.35 Impact Factor
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    • "Flavonoids have not been extensively explored in the area of biofilms as there is limited literature. However, among the few studied, dietary flavonoids present in citrus such as kaempferol and naringenin have been proved to act as quorum-sensing inhibitors by interfering with the interaction between acyl–homoserine lactones (AHLs, the signal molecules for Gram negative bacteria) and their receptors, leading to inhibition of biofilm formation (Cushnie and Lamb 2005; Vikram et al. 2010). Manner et al. (2013) in their study "
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    ABSTRACT: AimsThe increased microbial drug resistance due to biofilms and the side effects associated with the use of conventional drugs is still a major concern in the medical fraternity. This work evaluates the antibiofilm potential of flavonoids extracted from Moringa oleifera seed coat (SC) in search for green and effective alternatives for overcoming menace of biofilms. Methods and ResultsThe study evaluated the minimum inhibitory concentration (MIC) of flavonoids against respective test organisms, inhibition of initial cell attachment as well as disruption of preformed biofilms and metabolic activity of treated biofilms. Mutagenicity and cytotoxicity as well as characterization of the active component were also carried out. Although Pseudomonas aeruginosa showed the lowest MIC of 005mgml(-1), the action of flavonoids and gentamicin on initial cell attachment revealed a comparable effect against bacterial biofilms, i.e. Staphylococcus aureus and Pseudomonasaeruginosa with approx. 80% inhibition compared to Candida albicans. Disruption of the preformed biofilms revealed that susceptibility of P.aeruginosa began as early as 4h of exposure to flavonoids with 88% growth inhibition at the end of 24-h incubation. Encouragingly, t-test analysis on the effect of the extract and the standard antibiotic against each organism indicated no significant variance at P<005. A drastic low metabolic activity exhibited by the treated biofilms as compared to the untreated ones was further supportive of the antibiofilm potential of seed coat flavonoids. Conclusion The bioactive component from M.oleifera seed coat has exhibited antibiofilm potential against the test organisms belonging to Gram positive, Gram negative and yeast. Significance and Impact of the StudyAntibiofilm potential and biosafety of plant-based flavonoids from M.oleifera seed coat reveal a prospective active principle that could be of use in biofilm-associated menace.
    Journal of Applied Microbiology 11/2014; 118(2). DOI:10.1111/jam.12701 · 2.39 Impact Factor
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    • "Indeed many secondary plant metabolites with known antimicrobial potential have been found in honey (Adler 2000). These compounds have been shown to be highly plant specific and include radical scavenging activity, polyphenols and flavonoids that interfere with pathogen growth (Cushnie and Lamb 2005). The strength of antimicrobial effects can also depend on the interaction among different flavonoids (Mihai et al. 2012). "
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    ABSTRACT: Honeybee colonies offer an excellent environment for microbial pathogen development. The highest virulent, colony killing, bacterial agents are Paenibacillus larvae causing American foulbrood (AFB), and European foulbrood (EFB) associated bacteria. Besides the innate immune defense, honeybees evolved behavioral defenses to combat infections. Foraging of antimicrobial plant compounds plays a key role for this “social immunity” behavior. Secondary plant metabolites in floral nectar are known for their antimicrobial effects. Yet, these compounds are highly plant specific, and the effects on bee health will depend on the floral origin of the honey produced. As worker bees not only feed themselves, but also the larvae and other colony members, honey is a prime candidate acting as self-medication agent in honeybee colonies to prevent or decrease infections. Here, we test eight AFB and EFB bacterial strains and the growth inhibitory activity of three honey types. Using a high-throughput cell growth assay, we show that all honeys have high growth inhibitory activity and the two monofloral honeys appeared to be strain specific. The specificity of the monofloral honeys and the strong antimicrobial potential of the polyfloral honey suggest that the diversity of honeys in the honey stores of a colony may be highly adaptive for its “social immunity” against the highly diverse suite of pathogens encountered in nature. This ecological diversity may therefore operate similar to the well-known effects of host genetic variance in the arms race between host and parasite.
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