Quercetin: A Promising Flavonoid with a Dynamic Ability to Treat Various Diseases, Infections, and Cancers

Abstract

Quercetin is a multifaceted dietary flavonoid with a multitude of biologic activities that can be used to treat various ailments. These include cancer, bacterial and viral infections, cardiovascular disease, and diabetes. A greater emphasis on cancer is discussed within this paper by highlighting some of the beneficial qualities of quercetin without including other related dietary flavonoids and quercetin analogs. In vitro and in vivo analysis are evaluated without making recommendations on dosage, dosing regiments, or administration since quercetin has not been subjected to rigorous clinical trials despite the significant amount of research that has been conducted with quercetin.

Lycopene, sulforaphane, quercetin, and curcumin applied together show improved antiproliferative potential in colon cancer cells in vitro

“…The p53 protein, commonly known as “the guardian of the https://en.wikipedia.org/wiki/Genome,” acts as a regulator of DNA repair by stopping cell cycle at G1/S or G2/M phases, and due to major defects induces apoptosis (Vogt Sionov & Haupt, ). The assumption of the authors of the presented study is supported by a number of other studies which indicate p53 as an important molecular target of the examined phytochemicals (reviewed in Smith et al, ; reviewed by Teodoro et al, ; reviewed in Clarke et al, ; reviewed in Goel et al, ). The data presented in the presented study are consistent with results described by other researchers investigating aspects of the anticancer activity of natural compounds.…”

“…Several well‐designed, large population‐based studies have revealed that frequent consumption of cruciferous vegetables, three and more portions per week of, e.g., broccoli, cauliflower, cabbage, radish, horseradish, canola, mustard, and arugula, significantly decreases the relative risk of colon cancer development (Annema, Heyworth, McNaughton, Iacopetta, & Fritschi, ; Benito et al, ; Bosetti et al, ; Wu et al, ). The well‐examined, bioactive substances present in cruciferous vegetables are isothiocyanate sulforaphane (reviewed in Tortorella, Royce, Licciardi, & Karagiannis, ; reviewed in Clarke, Dashwood, & Ho, ) and the polyphenol quercetin, one of the most abundant flavonoid found in many other vegetables (not only cruciferous) and fruits, e.g., apples, berries, onions, capers, and radish (reviewed in Smith, Oertle, Warren, & Prato, ; reviewed in Boots, Haenen, & Bast, ). Studies in vitro (Constantinescu et al, ; Hashemzaei et al, ; Niestroy et al, ; Nishikawa et al, ; Pappa, Bartsch, & Gerhauser, ; Pereira et al, ; Yang et al, ; Zhang, Zhang, Yin, & Zhang, ) and in vivo (Hashemzaei et al, ; Matsukawa et al, ; Matusheski & Jeffery, ; Munday & Munday, ; Myzak, Dashwood, Orner, Ho, & Dashwood, ; Veeranki, Bhattacharya, Marshall, & Zhang, ; Yang et al, ) which show the effects of pure sulforaphane and quercetin, suggest that the beneficial impact of cruciferous consumption on colon cancer development is commonly linked to the presence of the mentioned phytochemicals.…”

Flavonoids From Endophytic Bacteria of Cosmos Caudatus Kunth. Leaf as Anticancer and Antimicrobial

“…Quercetin has extraordinary antioxidant properties caused by its pharmacophores B ring, and the group ONOO − makes quercetin actable as a strong inhibitor of lipid peroxidation. In addition to the antioxidant properties, quercetin may also increase glutathione concentrations potentially inhibiting free radical formation [16]. Quercetin is able to regulate the cycle of cancer cells by binding to multiple targets, for example, by blocking the cell cycle at the G2/M phase or G1/S transition and also capable of interfering with MMP, thus triggering the release of cytochrome c in the cytoplasm and the activation of caspase-3 and caspase-7 [17].…”

Saponins and Polyphenolics of Methanol Leaf Extract of Boswellia dalzielii Hutch

“…Furthermore, kaempferol is an inhibitor of the human monoamine oxidases (hMAO-A and hMAO-B) [25] and a potent superoxide scavenger, with an IC 50 of 0.5 µM [26]. Quercetin has the ability to scavenge free radicals, bind to transition metal ions due to the presence of pharmacophores and a catechol group found in ring B hence regarded as the most potent scavenger of 2 O − , and ONOO − among the flavonoids [27] and improves glutathione concentrations [28,29]. The flavonol group of flavonoids can react with a free radical, it donates a proton and becomes a radical itself, but the resulting unpaired electron is delocalized by resonance, making the flavonol radical too low in energy to be reactive [30].…”