Antimicrobial activity of flavonoids

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.

Effects of coadministration of natural polyphenols with doxycycline or calcium modulators on acute Chlamydia pneumoniae infection in vitro

“…They are important metabolites of plants in defense against radiation and microorganisms. 21 So far, most of the antibacterial agents from nature have been derived from microbial resources, but plant metabolites deserve consideration in this respect for at least two reasons. First, plants have exceptional ability to produce cytotoxic agents and second there is an ecological rationale that antimicrobial natural products should be present or plants following microbial attack to protect the producer from pathogenic microbes in its environment.…”

Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits

“…Polyphenolic compounds including anthocyanins possess antimicrobial activity against a wide range of microorganisms, especially in inhibiting the growth of food-borne pathogens [129]. Anthocyanins exhibit antimicrobial activity through several mechanisms, such as induced cell damage by destroying the cell wall, membrane, and intercellular matrix [101].…”

Determination of the antioxidant capacity, total phenolic and flavonoid contents of seeds from three commercial varieties of culinary dates

“…Flavonoids, which are chemically defined as benzo-γ-pyrone derivatives and consist of phenolic and pyran rings (Heim, Tagliaferro, & Bobilya, 2002), are in fact associated with potential bioactive properties (Heim et al, 2002;Ross & Kasum, 2002;FernandezPanchon, Villano, Troncoso, & Garcia-Parrilla, 2008). Their efficient use as natural colourings has been demonstrated a number of times (Bridle & Timberlake, 1997;Espin, Soler-Rivas, Wichers, & Garcia-Viguera, 2000), food antioxidants (Kranl et al, 2005;Capitani, Carvalho, Rivelli, Barros, & Castro, 2009), and antimicrobial agents (Xu & Lee, 2001;Cushnie & Lamb, 2005). In these terms, conventional and emerging technologies such as supercritical and subcritical, microwave-and ultrasound-assisted extraction can be used to develop a tailored-made process of extracting and purifying flavonoids from date seeds; however, more studies are needed to identify the most efficient, environmentally friendly and economically feasible method.…”