Quercetin as one of the most abundant represented biological valuable plant components with remarkable chemoprotective effects - A review

Abstract

As a consequence of environmental quality changes as well as changes in our population's lifestyle, there is rapidly increasing variability and many so-called lifestyle disorders, allergies, and food intolerances (also known as non-allergic food hypersensitivity). Unhealthy eating practices, an inappropriate food composition with an excessive energy intake, a high intake of saturated fats, simple sugars, and salt, as well as an inadequate intake of fibre, vitamins, and substances with preventive effects (such as antioxidants), are some of the factors causing this detrimental phenomenon. Enhanced consumption of plant foods rich in valuable secondary metabolites such as phenolic acids and flavonoids with the benefit on human health, food research focused on these components, and production of foods with declared higher content of biologically active and prophylactic substances are some ways how to change and improve this situation. A unique class of hydroxylated phenolic compounds with an aromatic ring structure are called flavonoids. One unique subclass of flavonoids is quercetin. This phytochemical naturally takes place in fruits, vegetables, herbs, and other plants. Quercetin and its several derivates are considered to be promising substances with significant antidiabetic, antibacterial, anti-inflammatory, and antioxidant effects, which could also act preventively against cardiovascular disease, cancer, or Alzheimer's disease.

Keywords: Flavonoid; Nutrition; Plant; Quercetin.

Fig. 1

A) Scientific papers (reviewed journal articles only) on quercetin over the past ten years (2014–2024); B) Fields of study; C) Most active countries that have published works on quercetin (Data were taken from Lens.org on May 23, 2024).

Fig. 2

The basic structure of flavonoids [8].

Fig. 3

Structure of most common types of flavonoids. Figure reproduced from Ref. [9] with permission from Taylor & Francis.

Fig. 4

Flavonoids biosynthesis pathway [11].

Fig. 5

Chemical structure of quercetin.

Fig. 6

Biosynthetic pathway of quercetin[4].

Fig. 7

Chemical structure of rutin.

Fig. 8

Quercetin absorption from the digestive tract. Figure reproduced from Ref. [101] with permission from Taylor & Francis.