Exploring the cholesterol‐lowering effects of cereal bran cell wall‐enriched diets

Abstract Cell wall polysaccharides (dietary fiber) in cereal grains contribute to health benefits. The novelty of the current study was an effort to explore the in vivo therapeutic potential of different cereal bran cell walls against hypercholesterolemia. For this purpose, the cell walls were isolated from different cereal brans (wheat, maize, oats, and barley), and the intake of these cereal bran cell walls was evaluated for their anti‐lipidemic activity in normal and hypercholesterolemic rats. The serum taken from the rats was tested for cholesterol, lipid, and triglyceride profiles before and after treatment. The outcomes of the current study have shown that the cereal cell wall has a significant hypercholesterolemia effect. The biochemical parameters of the control animals were within the normal clinical ranges, indicating that the experimental diets were safe. Among cereal bran cell walls, barley bran significantly decreased cholesterol (56.35 ± 1.35 mg/dL), low‐density lipoprotein (56.35 ± 1.05 mg/dL), triglycerides (105.29 ± 1.95 mg/dL), and increased high‐density lipoprotein level (48.35 ± 1.35 mg/dL). These findings provide conclusive evidence that the cereal cell wall is beneficial in the treatment of hypercholesterolemia and may potentially provide protection against other acute, recurring, or chronic illnesses.

comprises three primary constituents: embryo, endosperm, and bran, which is multilayered for reinforcement.The composition and properties of the cell wall of the complex structure that is the cereal kernel vary.The predominant constituent of the composition is starch, with proteins and non-starch polysaccharides accounting for 10%-15%, 3%-8%, and 70%-80%, respectively, of the total.Dietary or pharmaceutical reduction of total and LDL lowers CHD risk.Whole-grain diets reduce the risk of cancer, cardiovascular disease, and noninsulin-dependent diabetes.
Whole-grain fiber affects risk factors like blood glucose, insulin, and cholesterol, which may explain these findings.Studies have shown that soluble-fiber-rich whole grains like oats and barley reduce blood cholesterol better than insoluble-fiber-rich grains like wheat or rice.Adding dietary fiber, a variety of plant compounds that resist digestion by human gastrointestinal enzymes, lowers cholesterol (Noreen, Tufail, Ul Ain, et al., 2023).The structural or matrix fibers (lignins, cellulose, and some hemicelluloses) are insoluble in water, while the natural gel-forming fibers (pectins, gums, mucilages, and the rest of the hemicelluloses) are soluble.
Bran is the hard outer layer of grain left over after milling.Thickwalled cells in cereal bran include aleurone, testa, pericarp, and remnant endosperm tissue.Bran is found in rice, corn, wheat, oats, barley, rye, and millet (McRorie Jr et al., 2020;Semjon et al., 2020).
Hypocholesterolemia may be caused by increased bile acid excretion, fermentation-produced short-chain fatty acids, or small intestinal food absorption.In a crossover research, Whyte et al. explained how oat and wheat bran affect plasma lipids (Whyte et al., 1992).High-soluble oat fiber diets can significantly cut plasma total and LDL cholesterol in mildly hypercholesterolemic patients, lowering coronary heart disease risk (Tufail, Saeed, Afzaal, et al., 2021).Considering all the above, the cereal bran cell wall must be isolated and purified and used in goods to fight various diseases.Soluble fiber has the ability to bind cholesterol in the bowel and eliminate it from the body.This is because soluble fiber is not absorbed in the intestine during digestion.Water, protein, fat, carbohydrates, arabinoxylans, cellulose, lignin, fructans, β-glucans, nonstarch polysaccharides, phenolic acids, flavonoids, tocopherols, tocotrienols, c-oryzanol, and phytic acid are present in the bran cell wall (Noreen et al., 2021).The current study extracted and purified wheat, rice, maize, barley, oat, rye, and oat bran cell walls for nutritional characterization, product integration, and hyperglycemia and hyperlipidemia prevention.

| Procurement of raw materials
Two varieties of four cereal brans, i.e., wheat, barley, maize, and oat, were procured from Faisalabad.

| Isolation of cell walls
Cell walls from various grain brans were isolated and purified, and carbohydrates and proteins from endosperm tissue were extracted using the method of Brillouet et al. (1988)."First, 50 g bran was suspended in 0.1 M phosphate buffer (pH 7.5 I 1) with 1% sodium lauryl sulfate 2-mercaptoethanol and 1% sodium azide.Add 25 ml of 5 mg/mL alkaline protease to buffer and stir for 2 h at 40°C.The residue was rinsed and suspended in distilled water following centrifugation.After boiling for 15 min, 10 mL Termamyl 120 L was added and stirred at 95°C for 1 h.A sintered glass filter collected the residue, which was rinsed with 500 mL hot water, solvent-exchanged (ethanol, acetone), and oven-dried overnight at 40°C".

| Experimental animals
The hypocholestrolemic potential of wheat, maize, oats, and barley cell walls was tested on rats.The Animal Room of the Department of Physiology, Government College University, Faisalabad, housed 80 male Sprague Dawley rats (180-200 g).For 1 week, rats were fed a baseline diet to acclimate.Environmental conditions during the experiment included a 23 ± 2°C temperature, 55 ± 5% relative humidity, and a 12-h light-dark cycle.Dissecting certain rats at trial start provided baseline values for specified attributes.The Research Ethical Committee of Government College University, Faisalabad, accepted the methods.

| High cholesterol diet
Normal rats will be fed a high-cholesterol diet of 2.0% cholesterol and 0.5% cholic acid to produce hypercholesterolemia in all groups except T 0 .To monitor hypercholesterolemia induction, rats were examined periodically (Feng et al., 2019;Noreen, Rehman, et al., 2023).

| Kits
The Gamma Trade Company provided TC, LDL-C, VLDL, and HDL for pharmaceutical and chemical purposes.

| Animal experiment
After 1 week of adaptation, 80 rats were divided into two groups.As a negative control group (−ve), Group I (16 rats) was fed only the basal diet.Group II (64 rats) received a hypercholesterolemic diet without any medications for 2 weeks during the trial (Noreen, Rehman, et al., 2023).This group had four 16-rat subgroups.Disease-free male rats with an age range of 6-8 weeks and a weight of 180-200 g were included in the study, and diseased, underweight, and female rats were excluded from the study.Table 6 shows that the other four subgroups were fed 2% wheat, barley, maize, and oat bran cell walls for 3 weeks.

| Biochemical examination
Hematological parameters were measured in EDTA-treated tubes for baseline and follow-up testing.Fortnightly serum lipid profiling included cholesterol, LDL, HDL, and TG.The total cholesterol was determined using the Desai et al. (2006) method.HDL was measured using the technique mentioned by Alshatwi et al. (2010).LDL levels in sera samples were also reported according to Kim et al. (2011).
Triglycerides were measured using the methodology reported by Patel et al. (2013).

| Statistical analysis
Following parameter data collection, Statistix 8.1 was utilized to analyze the statistics.In the preliminary analysis of variety composition, a complete randomized design (CRD) was utilized.Analysis of variance (two-factor factorial) and least significant difference were subsequently utilized by Steel et al. to establish treatment significance over variety (Steel & Torrie, 1980).

| Total cholesterol (TC)
Cholesterol levels after consuming cereal grain cell walls are in

TA B L E 4
Effect of treatments on lowdensity lipoprotein level.
Cereal bran reduces the risk of chronic diseases (Knudsen et al., 1995;Saeed et al., 2021).The findings of this research suggested that the mean levels of cholesterol were higher after consuming selected cereal grain cell walls, as shown in Table 1.
The control group (T 0 ) exhibited maximal cholesterol levels of 62.30 ± 1.88 mg/dL and 62.84 ± 2.62 mg/dL, respectively, in trials I and II of study II (anti-hypercholesterolemic study).The mean cholesterol levels influenced by the cell walls of particular cereal grains were displayed.Maximum cholesterol levels for the control group (T 0 ) were recorded as 62.30 ± 1.88 mg/dL and 62.84 ± 2.62 mg/dL, respectively, in both trials of study II (antihypercholesterolemic study).In the normal study, T 3 cholesterol levels were recorded as 82.64 ± 5.28 mg/dL, whereas in the hypercholesterolemic study, they were reduced to 81.32 ± 3.55 mg/dL.
Trials I and II of the control group and trial I and II of the hypercholesterolemic group, respectively, observed reduced cholesterol levels in T 1 (80.19 ± 4.66, 79.25 ± 2.21, and 58.11 ± 3.11, respectively).In normal and hypercholesterolemic studies, than wheat bread (Momenizadeh et al., 2014).
In hypercholesterolemic study groups, the control group had the highest LDL levels (62.10 ± 1.08 mg/dL), followed by maize bran Note: T 0 = control diet; T 1 = wheat bran cell wall; T 2 = barley bran cell wall, T 3 = maize bran cell wall; T 4 = oat bran cell wall.
cell wall-fed rats (61.29 ± 0.41 mg/dL) and barley bran cell wall-fed rats (56.35 ± 1.05 mg/dL) in trial I.In trial II, the greatest LDL level (62.34 ± 2.62 mg/dL) was observed in T 0 , progressively decreasing in T 3 , T 4 , T 1 , and T 2 (56.35 ± 1.05 mg/dL).Mumford et al. showed that premenopausal women lacking estrogen had lower lipoprotein cholesterol after eating fiber (Mumford et al., 2011).Barley supplementation also altered cardiovascular disease biomarkers and lipid parameters, according to Behall et al.Because barley contains soluble fiber, total cholesterol dropped and high-density lipoprotein increased (Behall et al., 2004).In a randomized controlled experiment, Tighe et al. (2013) found that wheat and oat-based whole grain meals did not affect blood lipoprotein size and distribution in overweight middle-aged people.
The maximum HDL level (48.70 ± 1.35 mg/dL) was obtained in trial II (T 2 ), whereas the lowest was observed in trial I (T 0 ) (Table 3).
In trial I, T 2 had the highest HDL level, followed by T 1 , T 4 , T 3 , and T 0 .In trial II, T 2 had the highest HDL level, followed by T 1 and T 4 .
T  (Lupton et al., 1994).HDL increased dramatically, while total cholesterol, LDL, and triglycerides decreased.In a randomized controlled clinical trial, Gong et al. (2018) found that barley's high soluble fiber and beta glucan content reduced cholesterol better than wheat in hypercholesterolemic patients.
Due to its ability to bind bile acids, soluble fiber derived from barley reduces total cholesterol, triglycerides, and LDL (Zhu et al., 2015).Jenkins et al. investigated the impact of wheat bran supplementation on the serum lipid profile and discovered that it significantly decreased the triglyceride concentration in hyperlipidemic individuals (Jenkins et al., 1999).Furthermore, the effect of oat bran on lipoprotein parameters was assessed in a placebo-controlled study on subjects with hyperlipidemia, and it was observed that oat bran lowers the triglyceride level of lipid profile owing to the presence of high fiber contents (Bremer et al., 1991).Moreover, barley supplementation altered cardiovascular disease biomarkers and lipid parameters, according to Behall et al. (2004).

| CON CLUS IONS
These findings suggest that the cell wall has direct effects on the absorption of cholesterol in the small intestine.In the small intestine, cholesterol re-esterification is mediated by cholesterol acyltransferase, which may be inhibited by the cell wall.Among cereal bran cell walls, barley bran significantly decreased cholesterol T 4 cholesterol levels decreased to 81.44 ± 1.12, 80.82 ± 4.05,   59.29 ± 3.34, and 60.47 ± 2.96 mg/dL, respectively.The findings of this investigation mirrored those of a prior study conducted by AbuMweis et al., which explored the lipid-lowering effects of barley beta-glucan.In a dose-dependent manner, barley beta-glucan reduced total cholesterol and LDL (AbuMweis et al., 2010).Further, Moreira-Rosario et al. discovered that wheat germenriched bread did not change cardiovascular disease risk factors like cholesterol levels (Moreira-Rosário et al., 2019).In a randomized controlled experiment, Momenizadeh et al. studied how oat and wheat bread affected hypercholesterolemic individuals' lipid profiles.Beta glucan in oat bread lowered cholesterol more

(
56.35 ± 1.35 mg/dL), low-density lipoprotein (56.35 ± 1.05 mg/dL), triglycerides (105.29 ± 1.95 mg/dL), and increased high-density lipoprotein level (48.35 ± 1.35 mg/dL).As a result, the cereal bran cell walls and barley bran were proposed as a novel option for the clinical care of hyperlipidemic patients.The cell wall exhibited substantial hypocholestrolemic activity, indicating that the concentrations of the cell wall should be investigated further.

Table 3 .
In the control group (T 0 ), maximum cholesterol levels (62.30 ± 1.88 mg/dL and 62.84 ± 2.62 mg/dL) were observed in trial I and trial II of study II (anti-hypercholesterolemic study).Treatment plan.
Note: Different letters in the table indicate statistically significant differences between the samples while the level of significant is p= < .05.TA B L E 2Mean values for cell wall contents (g/100 g) of cereals bran.(maizecell wall) showed a considerable cholesterol drop in both ex-
Effect of treatments on cholesterol level.
in trial II of the normal investigation.In the antihypercholesterolemic investigation, T 0 (control diet) had the highest triglycerides (114.10 ± 1.18 mg/dL), whereas T 2 had the lowest (106.58 ± 4.91 mg/dL) TA B L E 3 Effect of treatments on triglyceride level.
A study byLupton et al. indicatedthat barley bran flour and oil raised total cholesterol in hypercholesterolemia individuals