**H.P. Vasantha Rupasinghe 1,2**


Received: 13 October 2020; Accepted: 15 October 2020; Published: 16 October 2020

In recent years, the interest in flavonoids as dietary bioactives to prevent human diseases, as well as their candidacy as pharmaceutical leads, has exponentially expanded. Flavonoids are a sub-class of plant polyphenols that have been shown to possess numerous health-promoting physiological benefits in a wide range of investigations from cell-based assays to epidemiological and human intervention studies. In this e-book editorial, a brief overview and insights into articles published in the Special Issue of *Molecules* titled "Flavonoids and Their Disease Prevention and Treatment" are provided. It is evident that all these papers contribute toward new knowledge to discover and validate beneficial physiological functions and the therapeutic potential of dietary flavonoids. Beyond their role as biologically active molecules of plant food, new insights are presented for the potential use of flavonoid derivatives as effective therapeutics to manage certain cancers. Flavonoids also offer promising applications in the management of obesity- and inflammation-associated disorders as well as the control of infectious diseases, including COVID-19.

Flavonoids are ubiquitously present in plant-based foods and natural health products. The molecule of flavonoids is characterized by a 15-carbon skeleton of C6-C3-C6, with the different structural configuration of subclasses. The major subclasses of flavonoids with health-promotional properties are the flavanols or catechins (e.g., epigallocatechin 3-gallate from green tea), the flavones (e.g., apigenin from celery), the flavonols (e.g., quercetin glycosides from apples, berries, and onion), the flavanones (e.g., naringenin from citrus), the anthocyanins (e.g., cyanidin-3-*O*-glucoside from berries), and the isoflavones (e.g., genistein from soya beans). Scientific evidence has strongly shown that regular intake of dietary flavonoids in efficacious amounts reduces the risk of oxidative stressand chronic inflammation-mediated pathogenesis of human diseases such as cardiovascular disease, certain cancers, and neurological disorders [1]. The physiological benefits of dietary flavonoids have been demonstrated to be due to multiple mechanisms of action, including regulating redox homeostasis, epigenetic regulations, activation of survival genes and signaling pathways, regulation of mitochondrial function and bioenergetics, and modulation of inflammation response. The role of flavonoids on gut microbiota and the impact of microbial metabolites of flavonoids on optimal health has begun to unravel. The complex physiological modulations of flavonoid molecules are due to their structural diversity. However, some flavonoids are not absorbed well, and their bioavailability could be enhanced through structural modifications and applications of nanotechnology, such as encapsulation. This Special Issue consists of four review articles on flavonoids and 13 original research articles, which cover the latest findings on the role of dietary flavonoids and their derivatives in disease prevention and treatment.
