Flavones and Related Compounds: Synthesis and Biological Activity

Abstract

This review focuses on the synthesis and biological activity of flavones and their related flavonoidic compounds, namely flavonols and aurones. Among the biological activities of natural and synthetic flavones and aurones, their anticancer, antioxidant, and antimicrobial properties are highlighted and detailed in this review. Starting from the structures of natural flavones acting on multiple anticancer targets (myricetin, genkwanin, and other structurally related compounds), new flavone analogs were recently designed and evaluated for their anticancer activity. The most representative compounds and their anticancer activity are summarized in this review. Natural flavones recognized for their antimicrobial properties (baicalein, luteolin, quercetol, apigenin, kaempferol, tricin) have been recently derivatized or structurally modulated by chemical synthetic methods in order to obtain new effective antimicrobial flavonoidic derivatives with improved biological properties. The most promising antimicrobial agents are systematically highlighted in this review. The most applied method for the synthesis of flavones and aurones is based on the oxidative cyclization of o-hydroxychalcones. Depending on the reaction conditions and the structure of the precursor, in some cases, several cyclization products result simultaneously: flavones, flavanones, flavonols, and aurones. Based on the literature data and the results obtained by our research group, our aim is to highlight the most promising methods for the synthesis of flavones, as well as the synthetic routes for the other structurally related cyclization products, such as hydroxyflavones and aurones, while considering that, in practice, it is difficult to predict which is the main or exclusive cyclization product of o-hydroxychalcones under certain reaction conditions.

Flavone Hybrids and Derivatives as Bioactive Agents

“…Recently, a review was published presenting only very few hybrids, focusing mor on flavone derivatives and especially the detailed synthetic procedures together with bi ological activities [65].…”

“…Aryl derivatives coupled with the 2-phenyl group via an amide bond (56) were synthesized using linear synthetic methods. The amide group was formed by the reactions of the corresponding carboxylic acids and amines [63][64][65]. Compounds 56a,b,c,d showed potent anticancer activity in several cancer cells, and proved to be potential lead molecules for further investigations [66].…”

An Overview of the Structure–Activity Relationship in Novel Antimicrobial Thiazoles Clubbed with Various Heterocycles (2017–2023)

“…Flavones are part of the large family of flavonoids, a widely distributed class of natural polyphenolic compounds. These impressive compounds exhibit a large variety of biological activities, including antimicrobial, antioxidant, and anticancer activities, thus constituting an attractive scaffold for drug design [ 85 ].…”

An Overview on the Structure-Activity Relationship in Novel Antimicrobial Thiazoles Clubbed with Various Heterocycles (2017-2022)

“…Flavones are part of the large family of flavonoids, a widely distributed class of natural polyphenolic compounds. These impressive compounds exhibit a large variety of biological activities, including antimicrobial, antioxidant, and anticancer activities, thus constituting an attractive scaffold for drug design [73].…”