Plant Flavonoids: Chemical Characteristics and Biological Activity

Abstract

In recent years, more attention has been paid to natural sources of antioxidants. Flavonoids are natural substances synthesized in several parts of plants that exhibit a high antioxidant capacity. They are a large family, presenting several classes based on their basic structure. Flavonoids have the ability to control the accumulation of reactive oxygen species (ROS) via scavenger ROS when they are formed. Therefore, these antioxidant compounds have an important role in plant stress tolerance and a high relevance in human health, mainly due to their anti-inflammatory and antimicrobial properties. In addition, flavonoids have several applications in the food industry as preservatives, pigments, and antioxidants, as well as in other industries such as cosmetics and pharmaceuticals. However, flavonoids application for industrial purposes implies extraction processes with high purity and quality. Several methodologies have been developed aimed at increasing flavonoid extraction yield and being environmentally friendly. This review presents the most abundant natural flavonoids, their structure and chemical characteristics, extraction methods, and biological activity.

UHPLC–MS/MS Analysis on Flavonoids Composition in Astragalus membranaceus and Their Antioxidant Activity

“…Flavonoids are a natural bioactive compound with C6-C3-C6 skeleton. They are commonly found in plant species, and possess good bioactivities which have been applied in nutraceutical, medicinal, and cosmetic products [ 5 ]. Many different subclasses of flavonoids have been described from A. membranaceus including flavone, flavonol, flavanone, flavanonol, chalcone, aurone, isoflavone, and pterocarpan [ 6 ].…”

Antioxidant and Anticancer Activities and Protein Interaction of the Oxidovanadium(IV) Naringin Complex

“…Flavonoids are an important group of natural substances, containing phenolic structures, which can be found in fruits, vegetables, and some beverages [1]. They are benzo-γpyrone derivatives consisting of aromatic (A and B) and pyrene (C) rings (Figure 1A) and are classified according to structural changes in hydroxylation pattern, conjugation between the aromatic rings, glycosidic moieties, and methoxy group [2,3]. These secondary metabolites have shown many and different applications, such as antiviral activity against zika virus infection [4], anti-hyperglycemic, liver protective [5], and anti-rheumatoid arthritis effects [6], antigenotoxic activity [7], and modulation of cardiovascular K + channels [8], just to mention some cutting-edge studies from the last few years.…”

“…Another important feature of flavonoids is their capacity to chelate metal ions and form coordination complexes through hydroxyl and keto groups [9]. There are three main chelating sites for metal ions in flavonoids, e.g., the 3 ,4 -dihydroxy group located on the B ring, the 3-hydroxy or 5-hydroxy, and the 4-carbonyl group in the C ring [3]. In 2 of 19 glycosylated flavonoids, metal coordination can also take place through hydroxy groups of the saccharide moiety [10].…”

Plant Natural Products as Antimicrobials for Control of Streptomyces scabies: A Causative Agent of the Common Scab Disease

“…Most recently, flavonoids have been examined for their antibacterial activity in food preservation (Wu and Zhou, 2021). There are several ways in which flavonoids impart their antibacterial activity (Dias et al, 2021). In some cases, flavonoids can bind and inhibit important proteins in cells.…”