A Review of Classification, Biosynthesis, Biological Activities and Potential Applications of Flavonoids

Abstract

Flavonoids represent the main class of plant secondary metabolites and occur in the tissues and organs of various plant species. In plants, flavonoids are involved in many biological processes and in response to various environmental stresses. The consumption of flavonoids has been known to reduce the risk of many chronic diseases due to their antioxidant and free radical scavenging properties. In the present review, we summarize the classification, distribution, biosynthesis pathways, and regulatory mechanisms of flavonoids. Moreover, we investigated their biological activities and discuss their applications in food processing and cosmetics, as well as their pharmaceutical and medical uses. Current trends in flavonoid research are also briefly described, including the mining of new functional genes and metabolites through omics research and the engineering of flavonoids using nanotechnology. This review provides a reference for basic and applied research on flavonoid compounds.

Reduction of flavonoid content in honeysuckle via Erysiphe lonicerae-mediated inhibition of three essential genes in flavonoid biosynthesis pathways

“…Post-inoculation of honeysuckle with E. lonicerae , we observed a consistent decrease in the expression of the phenylalanine deaminase gene ( LjPAL1 ) and a reduction in total PAL enzyme activity, which are pivotal in flavonoid and precursor synthesis ( Cochrane et al., 2004 ; Chen et al., 2023 ). Furthermore, significant down-regulation was noted in the flavonoid hydroxylase gene LjFNHO1 and flavonol glucosyltransferase gene LjFNGT1 , both integral to downstream flavonoid biosynthesis ( Shimada et al., 1999 ; Kubo et al., 2007 ; Chen et al., 2023 ; Negi et al., 2023 ). Post-inoculation, a decrease in downstream flavonoids such as chlorogenic acid, luteolin, quercetin, isoquercetin, and rutin was detected.…”

“…Flavonoids are acknowledged as pivotal medicinal components in plants, renowned for their wide array of therapeutic properties including anti-inflammatory, anti-microbial, anti-tumor, antioxidant, and anti-viral effects, particularly in the context of various chronic diseases ( Panche et al., 2016 ; Tungmunnithum et al., 2018 ; Chen et al., 2023 ). Moreover, they serve as key quality markers for honeysuckle, with the 2020 Chinese Pharmacopoeia specifying a minimum content threshold of 0.05% for the herb to be considered medicinally qualified ( Zheng et al., 2022 ).…”

Extraction of flavonoids from durian (Durio zibethinus) fruit rinds and evaluation of their antioxidant, antidiabetic and anticancer properties

“…Bioactive phenolics from durian rind exhibit various biological activities ( e.g . anticancer, anti‐inflammatory, antioxidant and antibacterial activities) that are beneficial and useful for pharmaceutical and nutritional applications (Kumar & Pandey, 2013; Dias & Pinto, 2021; Chen et al ., 2023). In this work, the Vietnamese durian fruit rinds were utilised as a material for extracting flavonoids.…”

Optimization of flavanonols heterologous biosynthesis in Streptomyces albidoflavus, and generation of auronols

“…These secondary metabolites are essential for the morphology and physiology of plants, displaying a wide range of functions, like cell growth regulation, pollinator insect attraction or protection against both biotic and abiotic stresses ( Dias et al, 2021 ). Humans can benefit from flavonoid intake as these compounds show diverse bioactive properties, such as antioxidant ( Chen et al, 2023 ; Liu et al, 2023 ), anti-inflammatory ( Chen et al, 2023 ; Liu et al, 2023 ), antitumor ( Redondo-Blanco et al, 2017 ) and cardioprotective ( Espírito-Santo et al, 2023 ), among many others.…”

“…Taxifolin ( Figure 1 ), also known as dihydroquercetin, is a flavanonol that, as aromadendrin, contains two stereocenters giving rise to four stereoisomers ( Bernatova and Liskova, 2021 ; Das et al, 2021 ). Many pharmacological properties are attributed to taxifolin, such as anti-inflammatory, antioxidant ( Liu et al, 2023 ), anti-Alzheimer, hepatoprotective, antiangiogenic, antimicrobial ( Bernatova and Liskova, 2021 ; Das et al, 2021 ), and also cosmetic ones ( Chen et al, 2023 ). Taxifolin has a higher antioxidant potential compared to other flavonoids, based on the disposition of its phenol groups and the elevated number of hydroxyl groups in its structure ( Das et al, 2021 ).…”