1. Introduction

Wheat (Triticum aestivum L.) is used as a staple food by human since the late Stone Age (ca. 6700

BC) [1]. It is also a promising source of bioactive compounds such as phenolic acids, tocotrienols, tocopherols, carotenoids, phytosterols, and flavonoids and antinutritional factors, such

as phytic acids and oxalates. Wheat cultivars exert antioxidant activity due to the presence of

phytochemicals, such as phenolic acids, carotenoids, anthocyanins, and tocopherols [2]. They

are also enriched with basic nutrients, i.e., proteins, vitamins, and minerals including calcium,

iron, zinc, phosphorous, etc. The percentages of the phytochemicals are greatly influenced by

multiple factors, such as soil type, cultivar type, topography, temperature, and humidity [3].

The population is more diverting toward the consumption of natural antioxidants due to their

safe status and effectiveness in the physiological system when compared to synthetic antioxidants. They neutralize the effects of free radicals, act as metal chelators, and terminate the

oxidative enzyme inhibitors and reactive oxygen species (ROS) reactions [4]. These free radicals enhance the uncontrolled growth of cells, produce the genetic defects in DNA, and leak

the antioxidant enzyme concentration from the cells [5]. Similarly, low-density lipoprotein

(LDL) is responsible for the development of coronary diseases [6]. The polyphenols from the

wheat have preventive role against reactive oxygen species through neutralizing the hydroxyl

and peroxy radicals, thereby suppressing the lipid peroxidation [7]. The human body contains two antioxidant systems: enzymatic including glutathione peroxidase and superoxide

dismutase (SOD) and nonenzymatic, i.e., vitamin C, β-carotene, vitamin E, and selenium [8].

3. Chemistry of wheat polyphenols

Wheat polyphenols are generally involved in defense mechanism against biotic and abiotic

stresses which are secondary metabolites [35]. The first substrate of the phenyl propanoid

pathway is phenylalanine, which initiates the biosynthesis of phenolic acids and then produces

the different phenolic acids and flavonoids [36]. Similarly, wheat phenolic compounds are categorized into derivatives of hydroxybenzoic acid or hydroxycinnamic acid. In hydroxybenzoic

acid derivatives, different compounds are present like gallic, vanillic, p-coumaric, hydroxybenzoic, and syringic acids, whereas hydroxycinnamic acids contain different derivatives, such

as ferulic acid, dehydrotrimers of ferulic acid, p-coumaric acids, and dehydrodimers [37, 38].

5. Wheat antioxidants in breakfast foods

Wheat-based breakfast is proven effective by promoting the health-endorsing perspectives due to

higher concentration of phenolic bioactive moieties. The acid and enzymatic hydrolysis increase

the solubility of wheat bioactive compounds. Similarly, food processing conditions mainly affect

the stability, distribution, and activity of wheat-based compounds [53]. The resultant breakfast

of wheat has been used to prevent from the proliferation of type 2 diabetes mellitus through

lowering the glycemic level in the postprandial phase [54]. The utilization of wheat in breakfast foods prevented the individuals from many disorders like obesity, hypertension, oxidative

stress, diabetes complications, mental disorders, digestive ailments, and cognition due to the

presence of diets higher in minerals and vitamins and lower in fat. These breakfasts are also

used to reduce the body mass index and incidences of obesity and overweight [55, 56]. Similarly,

wheat antioxidant-based breakfast significantly decreased hunger [57]. They also protect from

the bowel disorder due to dietary fiber. They enhanced the hydrated fecal weight between 10

and 20 g/100 g diet from a baseline of 21±1.5 g/100 g diet [58]

6. Absorption and bioavailability of wheat antioxidants

6.1. Syringic acid, sinapic acid, vanillic acid, and p-hydroxybenzoic acid

The information regarding pharmacokinetic parameters or the absorption characteristics of

syringic acid, sinapic acid, p-hydroxybenzoic acid, and vanillic acid is less. Therefore, it is need

of the time to conduct some studies regarding the absorption of these particular acids. Moreover,

these compound bioavailability is unknown. Which based on the derived innovative principle of

bioavailability and absorption for phenolic acid, nevertheless, we can now assess their bioavailability and absorption effectiveness. The substrate of monocarboxylic acid transporter meets the structural standards of all these compounds, that is, group of mono-anionic carboxyl and a

component of aromatic hydrophobic. Each phenolic acid inhibits the transport of fluorescein,

and they increased by the following order: syringic acid (105.9%)<sinapic acid (75.0%)<vanillic

acid (56.2%)<p-hydroxybenzoic acid (35.5%) [59]. Compared to fluorescein transport inhibition

by p-coumaric acid (85.2%), ferulic acid (52.4%), and caffeic acid (116.2%), each phenolic acid

monocarboxylic acid transporter affinity increased by the following order: p-hydroxybenzoic

acid>vanillic acid ¼ ferulic acid>p-coumaric acid, sinapic acid>syringic acid>caffeic acid. Hence,

monocarboxylic acid transporter vigorously absorbed the p-hydroxybenzoic acid, vanillic acid,

and sinapic acid through a mediated transport system.

6.2. Soluble, insoluble, and free conjugate-bound phenolic acid present in wheat

In grains, phenolic acid contributes the major portion, for instance, corn, wheat, and rice,

which are typically esterified with arabinose or galactose in pectic and hemicellulosis residues

in cell wall as well as occur as insoluble fraction (corn 85%, wheat 75%, and rice 62%) [67].

The major phenolic compounds present in grains is ferulic acid with free, soluble conjugated

and bound form present in 0.1:1:100 ratios [67]. Furthermore, the major contributors to the

total antioxidant activity are the bound phytochemicals e.g. 71% in rice, 90% in wheat, 58% in

oats and 87% in corn. The health consequences of dietary phenolic acid in wheat based food materials depends mainly on the bioavailability and absorption of soluble/ insoluble and free/

conjugate phenolic acids.

7. Health perspectives of wheat antioxidants

There are multiple evidences which prove that utilization of wheat antioxidants is linked with

the lower incidence of oxidative stress-related chronic diseases and age-related disorders,

such as carcinogenesis, cardiovascular diseases, type II diabetes, and obesity. They perform

health-endorsing perspectives due to the presence of vitamin C, vitamin E, carotenoids, phenolic acids, and flavonoids [25, 26]. They also facilitate digestion in human body by allowing

the bound phenolics in the colon [67]. Similarly, they improve insulin and inhibit the tumor

necrosis factor (TNF) alpha serum levels, lowering the serum cholesterol, fasting glucose, and

triglyceride. They also exert anticancer effects on cell growth and apoptosis of human breast

cancer cells such as MCF-7 and MDA-MB-231 [72].

The fact is that diet can completely change the life quality and human health. Wheat has

numerous essential nutrients, which are important part of diet. It is one of the most dominating nutritious crops. Intake of whole grain or wheat reduces the cardiovascular risk and diabetes [73]. The antioxidants of wheat and the insoluble fibers impart the valuable properties. Nevertheless, metabolism and cholesterol biosynthesis are directly standardized through

wheat antioxidants as compares to antioxidative agents, which are acting simply. The productive impacts are examined regarding the effect of antioxidants present in wheat on the

enzymes which participate in cholesterol biosynthesis.