Article

Antimicrobial activity of flavonoids

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.

5 Bookmarks
 · 
686 Views
  • Source
    01/2014; 8(6):35-40. DOI:10.9790/2402-08623540
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Reformulation of existing processed food or formulation of new foods using natural products (plant-based) will inherently confer to new products with less calories, fat, salt, phosphates and other synthetic components, and higher amounts of fibre, antioxidants, vitamins and other beneficial components. Plant ingredients, such as food plant powders, are currently being used in food manufacturing, predominantly for flavouring and colouring purposes. To expand their use as a food ingredient, freeze-dried powders representing major vegetable groups were characterised by targeted LC-MS/MS analysis of their phytochemicals. All the plant powders were found to be rich in flavonoids, phenolic acids and derivatives; total content in these compounds varied from around 130mgkg(-1) (green pea) to around 930mgkg(-1) (spinach). The food plant powders' phytochemical content represents valuable information for the food industry in the development of healthier novel foods and for the reformulation of existing food products in relation to antioxidants, food preservatives and alternatives to nitrite use. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Food Chemistry 02/2015; 179. DOI:10.1016/j.foodchem.2015.01.128 · 3.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Saponins are triterpenic or steroidal glycosides largely distributed in plant kingdom, which have many physicochemical (foaming, emulsification, solubilization, sweetness, bitterness) and biological properties (haemolytic, antimicrobial, antioxidant, moluscacide, insecticide, ichthyocide), which are exploited in many applications in food, cosmetics and pharmaceuticals industries, and also in soil bioremediation. Among the saponins properties, critical micellar concentration (CMC), maximum surface density and aggregation number (number of monomers in a micelle) are of great importance for application as surfactants and foaming agents. These are influenced by variables such as temperature, salt concentration, aqueous phase pH, solvent concentration and type (ethanol, methanol). The objective of this work was to evaluate some functional properties as critical micellar concentration (CMC), antimicrobial and antioxidant activities of two different saponins originated from Brazilian agrobiodiversity: sisal (Agave sisalana), with steroidal aglycone, and jua (Ziziphus joazeiro), a triterpenic aglycone. The variation of CMC from jua and sisal saponins was measured against parameters as temperature, pH and NaCl (%m/v) concentration, using turbidimetric titration (spectrophotometry), and for each CMC, it was detected the respective surface tension. The highest reduction on CMC values from jug saponins can be observed in neutral pH, near room temperature (25-30 degrees C) and saline concentrations among 2 and 4% m/v, while for sisal saponins, the conditions were pH between 3 and 4 with near room temperature; or pH among 10-11 with temperatures around 55-60 degrees C; and saline concentration from 2 to 6% m/v. Antioxidant activity of isolated saponins from jua and sisal was very low, represented only 25% of the antioxidant activity reached by its corresponding raw extracts (saponins and phenolics). Jug saponins presented antifungal activity against Candida albicans (156 mu g/mL) and Aspergillus niger (312.5 mu g/mL), while sisal saponins possessed no antimicrobial activity.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 09/2013; 436:736-743. DOI:10.1016/j.colsurfa.2013.08.007 · 2.35 Impact Factor

Full-text (2 Sources)

Download
3,203 Downloads
Available from
Jun 2, 2014