Acid-activated corn silk as a promising phytosorbent for uptake of Malachite green and Cd (II) ion from simulated wastewater: equilibrium, kinetic and thermodynamic studies

Malachite green (MG) dye and cadmium metal ion are toxic pollutants that should be removed from aqueous environment. The recent study aimed to examine the adsorption behavior of MG dye and Cd (II) from wastewater onto low-cost adsorbent prepared by activating corn silk with nitric acid (ACS) and characterized by SEM, FTIR, XRD, BET and TGA. The optimum MG and Cd (II) adsorption was observed at pH 7 and pH 9 and maximum uptake of both pollutants was at 0.5 g dosage, 60 mins contact time and 20 mg/L initial concentration. The retention of dye and metal ion by the studied adsorbent was best fit to Langmuir isotherm and Pseudo-second order kinetics. The maximum monolayer coverage capacity of ACS for MG dye and Cd (II) ion was 18.38 mg/g and 25.53 mg/g, respectively. Thermodynamic studies predicted a spontaneous reaction with exothermic process for MG dye whereas an endothermic and spontaneous process was confirmed for Cd ion based on estimated parameters. The adsorption mechanism of MG dye and Cd (II) uptake was by combination of electrostatic interaction, pore diffusion, ion exchange, pie-pie attraction, hydrogen bonding, and complexation. The adsorbed pollutants were effectively desorbed with significant regeneration efficiency after successive five cycles that proved the potential of low-cost biosorbent for selective sequestration of cationic dye and divalent metal ion from effluents.

An Umbrella Insight into the Phytochemistry Features and Biological Activities of Corn Silk: A Narrative Review

Corn silk (Zea mays L.) is the stigma of an annual gramineous plant named corn, which is distributed in many regions worldwide and has a long history of medicinal use. In recent years, with the sustainable development of traditional Chinese medicine, studies of corn silk based on modern technologies, such as GC-MS, LC-MS, and other analytical means, have offered more comprehensive analyses. Phytochemistry studies have shown that the main bioactive components in corn silk include flavonoids, polyphenols, phenolic acids, fatty acids, and terpenoids. Pharmacological studies have shown that corn silk extract has various pharmacological effects, such as reducing blood lipids, lowering blood pressure, regulating blood sugar levels, anti-inflammatory effects, and anti-oxidation effects. In this paper, the related research on corn silk from the past few years is summarized to provide a theoretical reference for the further development and utilization of corn silk.

Waste to Medicine: Evidence from Computational Studies on the Modulatory Role of Corn Silk on the Therapeutic Targets Implicated in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and/or defective insulin production in the human body. Although the antidiabetic action of corn silk (CS) is well-established, the understanding of the mechanism of action (MoA) behind this potential is lacking. Hence, this study aimed to elucidate the MoA in different samples (raw and three extracts: aqueous, hydro-ethanolic, and ethanolic) as a therapeutic agent for the management of T2DM using metabolomic profiling and computational techniques. Ultra-performance liquid chromatography-mass spectrometry (UP-LCMS), in silico techniques, and density functional theory were used for compound identification and to predict the MoA. A total of 110 out of the 128 identified secondary metabolites passed the Lipinski's rule of five. The Kyoto Encyclopaedia of Genes and Genomes pathway enrichment analysis revealed the cAMP pathway as the hub signaling pathway, in which ADORA1, HCAR2, and GABBR1 were identified as the key target genes implicated in the pathway. Since gallicynoic acid (-48.74 kcal/mol), dodecanedioc acid (-34.53 kcal/mol), and tetradecanedioc acid (-36.80 kcal/mol) interacted well with ADORA1, HCAR2, and GABBR1, respectively, and are thermodynamically stable in their formed compatible complexes, according to the post-molecular dynamics simulation results, they are suggested as potential drug candidates for T2DM therapy via the maintenance of normal glucose homeostasis and pancreatic β-cell function.

Role of corn silk for the treatment of Alzheimer's disease: A mechanism research based on network pharmacology combined with molecular docking and experimental validation

This study aimed to research the possible mechanism and effect of active ingredients of corn silk on Alzheimer's disease (AD) by the method of network pharmacology, molecular docking, and animal experiments. The active ingredients of Corn silk were obtained by searching the TCMSP database and the targets corresponding to the active ingredients of Corn silk were obtained through the TCMSP and SwissTargetPrediction platforms, and the AD targets were obtained in the GeneCards, OMIM, and DisgeNET databases. Cytoscape was employed for creating the "active ingredient-target" relationship network; STRING and Cytoscape for creating the protein-protein interaction (PPI) network. Besides, Meta scape was used for Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the intersecting targets; AutoDockTools and Pymol for molecular docking and visualization of core ingredients and core targets; and animal experiments for verifying the anti-AD effect of luteolin. A total of 12 active ingredients of corn silk were screened, including 465 targets and 209 intersected targets. Moreover, GO functional analysis results showed that the anti-AD effect of corn silk was mainly reflected in phosphotransferase activity, response to hormone, membrane raft, etc.; KEGG results indicated the main pathways involving cancer, Alzheimer disease, etc.; and the molecular docking results revealed excellent binding of the core ingredients (α-tocopheryl quinone, luteolin, etc.) to the core targets. Besides, the outcomes of animal experiments exhibited that luteolin not only reduced the expression of inflammatory factors TNF-α and IL-1β in mice but also attenuated inflammation. With the help of network pharmacology and experimental validation, the material basis and mechanism of the anti-AD of corn silk have been explored in this study. Briefly speaking, luteolin from corn silk plays an anti-AD role by inhibiting inflammation.

Antioxidant, Anti-Tyrosinase, and Anti-Skin Pathogenic Bacterial Activities and Phytochemical Compositions of Corn Silk Extracts, and Stability of Corn Silk Facial Cream Product

Zea mays L. Poaceae stigma (corn silk, CS) is a byproduct of agricultural waste and is used as a traditional herb in many countries. CS is rich in chemical compounds known to benefit human health and is also a remedy for infectious diseases and has anti-proliferative effects on human cancer cell lines. In the present study, CS extract has been evaluated for its antioxidant, antibacterial, and anti-tyrosinase activities and its phytochemical composition. The higher total phenolic and flavonoid contents were found in the ethanolic extract of corn silk (CSA), at 28.27 ± 0.86 mg gallic acid equivalent/g extract and 4.71 ± 0.79 mg quercetin equivalent/g extract, respectively. Moreover, the antioxidant content of CSA was found at 5.22 ± 0.87 and 13.20 ± 0.42 mg gallic acid equivalent/g extract using DPPH and reducing power assays. Furthermore, the ethanolic extract of corn silk showed tyrosinase inhibition with an IC50 value of 12.45 µg/mL. The bacterial growth inhibition of CSA was tested using agar disc diffusion and broth dilution assays against Cutibacterium acnes and Staphylococcus epidermidis. It was found that CSA inhibited C. acnes and S. epidermidis with an inhibition zone of 11.7 ± 1.2 and 9.3 ± 0.6 mm, respectively. Moreover, the CSA showed MIC/MBC of 15.625 mg/mL against C. acnes. The following phytochemical compounds were detected in CSA: cardiac glycosides; n-hexadecanoic acid; hexadecanoic acid, ethyl ester; oleic acid; and 9,12-octadecadienoic acid, ethyl ester. After the corn silk cream product was formulated, the product demonstrated stability without phase separation. This research is beneficial for promoting effective ways to use agricultural waste while utilizing the antioxidant, anti-tyrosinase, and antibacterial activities of corn silk. Moreover, the use of technology and innovation to obtain high-value CS extract will benefit the development of commercial cosmetic products by providing safe, natural, and quality ingredients to the consumer.

Modulatory Effects of Co-Fermented Pu-erh Tea with Aqueous Corn Silk Extract on Gut Microbes and Fecal Metabolites in Mice Fed High-Fat Diet

Pu-erh tea is recognized for its weight loss effects, but its potential association with gut microbiota and metabolites remains unclear. This research explored the alterations in gut flora and metabolite composition upon treatment with a co-fermented Pu-erh tea with an aqueous corn silk extract (CPC) in obese mice by employing integrated 16S ribosomal RNA gene sequencing and untargeted metabolomics processes. For 8 weeks, mice were fed control, high-fat, and high-fat diets which included a 46 mg/mL CPC extract. The CPC extract the alleviated high-fat diet (HFD), it stimulated systemic chronic inflammation, and it reduced the body weight, daily energy consumption, and adipose tissue weight of the mice. It also modified the gut microbiota composition and modulated the Lactobacillus, Bifidobacterium, Allobaculum, Turicibacter, and Rikenella genera. Fecal metabolomics analysis revealed that the CPC extract influenced the caffeine, cysteine, methionine, tryptophan, biotin metabolism pathways, primary bile acid, and steroid biosynthesis. This research revealed that the CPC extract could inhibit HFD-stimulated abnormal weight gain and adipose tissue accumulation in mice, and modulate mice gut microbiota composition and multiple metabolic pathways.

Protective effect of aqueous and methanolic extracts of corn silk on nicotine-induced reproductive system disorders in male mice

OBJECTIVE

The protective effect of aqueous and methanolic extracts of corn silk on reproductive disorders induced by nicotine was investigated in the present study.

METHODS

In this experimental study, 30 male NMRI mice (25-30gr) were divided into 5 groups: controls, sham, nicotine 2.5mg/kg, nicotine+aqueous extract of corn silk 400mg/kg, and nicotine+methanolic extract of corn silk 400mg/kg for 34 days. One day after the last nicotine and extracts administration, the serum samples were collected through cardiac puncture for hormonal measurements, and the testis and tail of the epididymis were isolated for the testis antioxidant, morphology, histopathology assessments, and sperm count.

RESULTS

Luteinizing hormone (LH) and malondialdehyde (MDA) increased in the nicotine group. Testosterone, sperm count, and glutathione (GSH) decreased when compared to the control group. Both aqueous and methanolic extracts of corn silk led to the improvement of mentioned changes; Except for GSH, because only treatment with methanolic extract could lead to its increase (p<0.05). Nicotine decreased the thickness of the epithelium of seminiferous tubules and the separation between them, and the administration of corn silk extracts improved that.

CONCLUSIONS

Nicotine consumption increased oxidative stress, LH levels, and decreased testosterone and sperm count, which indicate the induction of primary hypogonadism in animals. Moreover, the use of corn silk extracts has recovered the amounts of sex hormones and sperm count to normal conditions by reducing lipid peroxidation.

Optimizing extraction conditions and isolation of bound phenolic compounds from corn silk (Stigma maydis) and their antioxidant effects

During the processing of maize, Stigma maydis, also known as corn silk, is normally discarded as waste. Phytochemical research was carried out on the S. maydis to use it as a valuable source of bioactive components. This research aimed to maximize the recovery of free and bound phenolic compounds from corn silk under optimal experimental conditions. Response surface design was operated to optimize the alkaline hydrolysis extraction of bound phytochemicals from corn silk based on total phenolic content and DPPH radical scavenging activity. The optimum conditions (i.e., NaOH concentration 2 M, digestion time 135 min, digestion temperature of 37.5°C, the solid-to-solvent ratio of 1:17.5, and acetone) were obtained. The optimum parameters were used to extract the corn silk. The structures of two compounds isolated from ethyl acetate extracts were then identified as friedelin (1) and (E)-4-(4-hydroxy-3-methoxyphenyl) but-3-en-2-one (2). The DPPH, H₂ O₂ , and ABTS % inhibition of the compounds is as follows: compound (1) 74.81%, 76.8%, 70.33% and compound (2) 70.37%, 56.70% and 57.46%, respectively. The current study has opened previously unexplored perspectives of the composition of bound compounds in corn silk and established the foundations for more effective processing and utilization of corn waste. PRACTICAL APPLICATION: Bound phenolic compounds from corn silk under optimal experimental conditions were obtained. Corn silk can be utilized as a type of medicinal herb as well as a source of inexpensive natural antioxidants.

A Physicochemical Study of the Antioxidant Activity of Corn Silk Extracts

Corn silk (CS) extracts are reported to contain flavonoids (appx. 59.65 mg quercetin/g), polysaccharides (appx. 58.75 w.%), steroids (appx. 38.3 × 10^-3 to 368.9 × 10^-3 mg/mL), polyphenols (appx. 77.89 mg/GAE/g) and other functional biological substances. This study investigated the antioxidant activity of corn silk extracts related to their functional compounds. The radical scavenging effect of corn silk extracts was evaluated by the spin-trapping electron paramagnetic resonance (EPR) technique, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonate) (ABTS^•+) free radical measurement, ferric ion-reducing antioxidant power, and copper ion reductive capacity. It was found that the maturity stage of CS plant materials and the applied extraction procedure of their bioactive compounds have a profound effect on the radical scavenging capacity. Differences in the antioxidant activity of the studied corn silk samples based on their maturity were also confirmed. The strongest DPPH radical scavenging effect was observed for the corn silk mature stage (CS-M)stage (CS-MS) (65.20 ± 0.90)%, followed by the silky stage (CS-S) (59.33 ± 0.61)% and the milky stage (CS-M) (59.20 ± 0.92)%, respectively. In general, the final maturity stage (CS-MS) provided the most potent antioxidant effect, followed by the earliest maturity stage (CS-S) and the second maturity stage (CS-M).

Valorization and characterization of corn by-product polyphenols through green extraction technologies

The amount of food waste throughout the world has become quite alarming and is contributing to lower food resources. The study aimed to extract and characterize the polyphenols from corn silks at immature and mature stages through conventional and green extraction techniques. Purposely, corn silks, which are some of the by-products of corn, (Zea mays L.) were collected and subjected to proximate analysis including moisture, ash, protein, fiber, and minerals. Secondly, the antioxidants from both immature and mature corn silks were extracted by techniques involving supercritical and ultrasound extraction alongside conventional extraction. The results displayed a promising quantity of protein and fiber along with calcium, magnesium, sodium potassium, and copper. Among the extraction techniques, supercritical extraction at 3,000 Pa acquired the highest total phenolic contents (TPC), total flavonoids (TF), 2, 2-diphenylpicrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP) activities as 128.08 ± 3.74 mg GAE/100 g, 86.73 ± 2.75 mg CE/100 g, 106.73 ± 5.10%, and 73.52 ± 2.33 μM Fe + 2/g, respectively, followed by the ultrasound and conventional extraction techniques. Between the immature and mature corn silks, the highest antioxidant activity was displayed by immature corn silks.

Flavonoids with antioxidant and tyrosinase inhibitory activity from corn silk (Stigma maydis)

Corn silk (Stigma maydis), being the styles and stigmas of maize, is a famous traditional medicine and functional tea in China. Research into the chemical composition of corn silk led to the identification of an unreported flavone (1, silkone A), accompanying with three known flavonoids (2-4). And their structures were elucidated through comprehensive spectroscopic analysis. Each obtained compound was evaluated for antioxidant capacity by DPPH, ABTS and FRAP assays. As a result, all tested compounds exhibited stronger radicals scavenging activities than Trolox in ABTS radical assay and displayed relatively weak antioxidant capacity in the other two experiments. Tyrosinase inhibitory activities of compounds 1-4 were also investigated, and compounds 3 and 4 demonstrated moderate inhibitory activities to tyrosinase with IC₅₀ values of 0.49 and 0.21 mM, respectively, which was further investigated through molecular docking calculation. These results may contribute to the development of novel antioxidants and tyrosinase inhibitors from corn silk.

Growing and laying performance of two different-plumage color Japanese quail varieties supplemented with corn silk in their diet

The current study aimed to investigate the dietary supplementation effect of corn silk (CS) on performance and blood chemistry of brown and white-feathered quails during the grower and layer periods. Japanese quails of brown and white-feathered color (180 birds/variety at 2 wks old) were randomly allotted into three groups with 3 replicates each (n = 20 birds/replicate). Corn silk powder (CS) was supplemented to the basal diet at 0, 1, and 2% of the diet for each quail variety for 1-month growing period, then continued for another 6-wk laying period to assess the egg production and egg quality characteristics. CS supplementation at 1% and 2% for brown and white-feathered quails respectively improved their growth performance (body weight and weight gain), carcass yield, and intestinal villi length with increasing feed consumption but without changes in feed conversion ratio. In both quail varieties, CS addition had a hypolipidemic effect, confirmed by lowering serum triglyceride (TG), cholesterol (CHO), and low density lipoprotein (LDL) while increased high density lipoprotein (HDL) concentrations (P < 0.05) with a clear response observed in white quails than the brown ones. Besides, CS supplementation increased (P = 0.002) hen day egg production in brown feathered quails, while reducing it in the white-feathered quails compared with the CS-free diet. The increased egg production was not significantly (P > 0.05) correlated with lower content of TG and CHO, while significantly increased the antioxidant content in both quail varieties (P < 0.05). Moreover, CS dietary supplementation significantly enhanced (P = 0.003) the yolk color, especially in brown-feathered quail. In conclusion, CS can be safely supplemented to the Japanese quail diet (1% and 2% for brown-feathered and white-feathered quails respectively) to improve growth performance, and egg quality characteristics.

Modulation of gut microbiota and fecal metabolites by corn silk among high-fat diet-induced hypercholesterolemia mice

Corn silk (CS) is known to reduce cholesterol levels, but its underlying mechanisms remain elusive concerning the gut microbiota and metabolites. The aim of our work was to explore how altered gut microbiota composition and metabolite profile are influenced by CS intervention in mice using integrated 16S ribosomal RNA (rRNA) sequencing and an untargeted metabolomics methodology. The C57BL/6J mice were fed a normal control diet, a high-fat diet (HFD), and HFD supplemented with the aqueous extract of CS (80 mg/mL) for 8 weeks. HFD-induced chronic inflammation damage is alleviated by CS extract intervention and also resulted in a reduction in body weight, daily energy intake as well as serum and hepatic total cholesterol (TC) levels. In addition, CS extract altered gut microbial composition and regulated specific genera viz. Allobaculum, Turicibacter, Romboutsia, Streptococcus, Sporobacter, Christensenella, ClostridiumXVIII, and Rikenella. Using Spearman’s correlation analysis, we determined that Turicibacter and Rikenella were negatively correlated with hypercholesterolemia-related parameters. Fecal metabolomics analysis revealed that CS extract influences multiple metabolic pathways like histidine metabolism-related metabolites (urocanic acid, methylimidazole acetaldehyde, and methiodimethylimidazoleacetic acid), sphingolipid metabolism-related metabolites (sphinganine, 3-dehydrosphinganine, sphingosine), and some bile acids biosynthesis-related metabolites including chenodeoxycholic acid (CDCA), lithocholic acid (LCA), ursodeoxycholic acid (UDCA), and glycoursodeoxycholic acid (GUDCA). As a whole, the present study indicates that the modifications in the gut microbiota and subsequent host bile acid metabolism may be a potential mechanism for the antihypercholesterolemic effects of CS extract.

Medicinal Plants Extracts Impact on Oxidative Stress in Mice Brain Under the Physiological Conditions: the Effects of Corn Silk, Parsley, and Bearberry

This study was performed to examine the effects of medicinal plant extracts of corn silk (Stigma maydis), parsley leaf (Petroselini folium), and bearberry leaf (Uvae ursi folium) on antioxidant status of the brain of experimental animals (mice) under the physiological conditions. Biological properties of these plants are insufficiently investigated and the aim was to explore their possible antioxidant effects that can alleviate oxidative damage of the brain tissue. Corn silk extract showed positive effect on activities of antioxidant enzymes in mice brain tissue. Parsley extract induced the increase in glutathione content and decrease of lipid peroxidation. Bearberry leaf extract induced catalase activity and decrease of hydroxyl radical content, while malonyldialdehide accumulation was maintained at the control level. Results obtained in this study support the use of corn silk, parsley and bearberry leaves as natural antioxidant sources in the prevention and treatment of brain tissue damages and different diseases caused by oxidative stress.

Effect of Corn Silk Aqueous Extract on Brown Adipose Tissue of Embryos and Neonates of Diabetic Pregnant Mice: A Histological Study

Context

Many congenital malformations are seen increasingly, due to diabetic mothers causing a burden on health systems. Corn silk (CS) extract has been used as a natural hypoglycemic treatment. However, its teratogenic safety was not studied.

Aims

Therefore, in this study, we examine the effect of CS aqueous extract on fetuses, offspring of normal and diabetic female mice treated with CS aqueous extract.

Settings and Design

Pregnant female mice were divided into two groups diabetic and nondiabetic. Then, each of these groups was divided into control and treated.

Subjects and Methods

A daily dose of 4 g/kg of CS aqueous extract was given orally to the treated groups, control groups were given distilled water. The collection of samples was at day 16.5 of pregnancy, and neonates. Brown adipose tissue (BAT) in the sections of the preserved sample was examined.

Statistical Analysis Used

BAT areas were measured from 10 samples of each treatment age group in 2 sections. Data were analyzed with one-way ANOVA, then, two-independent sample test (Mann-Whitney) was done to test the significance of differences between groups.

Results

The BAT areas were negatively affected by diabetes and the extract. Both the extract and diabetes caused an increase in fat accumulation in the adipocytes with varying degrees.

Conclusions

This study showed for the first time to our knowledge that the use of CS aqueous extract during pregnancy affected BAT organization and area, and that the used dose did not decrease the malformations caused by diabetes. More studies with different doses should be investigated.

Extraction Optimization of Polysaccharides From Corn Silk and Their Antioxidant Activities in vitro and in vivo

Response surface technique was employed for improving the extraction of corn silk polysaccharides (CSP). Temperature, liquid-to-solid ratio, and per extraction time were all examined as separate factors. The optimal extraction parameters were determined by fitting experimental data to a second-order polynomial; a liquid-to-solid ratio of 21.5 ml/g, temperature equivalent to 88°C, and extraction time of 1.87 h. The experimental yield of the extracted polysaccharides following the application of these conditions was 4.33 ± 0.08% (dry weight), which fit quite well with the predicted value. CSP’s strong scavenging capabilities against hydroxyls, 1,1-diphenyl-2-picrylhydrazyl radicals, and superoxide anions along with its excellent reducing potential, were demonstrated in an in vitro antioxidant experiment. Meanwhile, in vivo testing revealed that CSP substantially enhanced glutathione peroxidase and superoxide dismutase activities. The Malondialdehyde levels in the liver and serum of aged mice also underwent a decrease. This study found that CSP has a substantial antioxidant potential in vitro and in vivo, suggesting that it might be used as an antioxidant in food and medicine.

Hypouricemia effects of corn silk flavonoids in a mouse model of potassium oxonated-induced hyperuricemia

The hypouricemic effect of corn silk flavonoids (CSFs) in vivo that were extracted by ethanol and fractionated by continuous elution with 40% (CSF-A) and 60% (CSF-B) ethanol solutions on polyamide column were investigated in this study. CSFs reduced serum uric acid (UA) level in a mouse model of potassium oxonate-induced hyperuricemia. CSF-B had the best hypouricemic effect, as it decreased the serum UA level by 26.69% and xanthine oxidase (XO) activity in the serum by 11.29%. The mechanism of action of CSF-B was related to the inhibition of XO activity and the promotion of UA excretion. CSF-B was found to contain 12 kinds of major flavonoids, five of which were speculated to influence its activity in the hyperuricemia mice. The five flavonoids were apigenin-6-C-glucoside-7-O-glucoside, kaempferol-3-O-rutinoside, luteolin-7-glucoside, luteolin-3',7-di-O-glucoside, and naringenin, respectively. Structure analysis revealed that C-4', C5 hydroxyl groups, and C2=C3 double bonds in CSF-B gave the latter its hypouricemic effect. PRACTICAL APPLICATIONS: The prevalence of hyperuricemia has increased in recent times. Current hypouricemic drugs have side effects and can easily lead to various complications. Therefore, it is of great practical significance to find safer and more effective hypouricemic drugs. This study demonstrated that corn silk flavonoids may be used as a dietary supplement to manage hyperuricemia.

Potential Effect of Polyphenolic-Rich Fractions of Corn Silk on Protecting Endothelial Cells against High Glucose Damage Using In Vitro and In Vivo Approaches

Endothelial cell dysfunction is considered to be one of the major causes of vascular complications in diabetes. Polyphenols are known as potent antioxidants that can contribute to the prevention of diabetes. Corn silk has been reported to contain polyphenols and has been used in folk medicine in China for the treatment of diabetes. The present study aims to investigate the potential protective role of the phenolic-rich fraction of corn silk (PRF) against injuries to vascular endothelial cells under high glucose conditions in vitro and in vivo. The protective effect of PRF from high glucose toxicity was investigated using human umbilical vein endothelial cells (HUVECs). The protective effect of PRF was subsequently evaluated by using in vivo methods in streptozotocin (STZ)-induced diabetic rats. Results showed that the PRF significantly reduced the cytotoxicity of glucose by restoring cell viability in a dose-dependent manner. PRF was also able to prevent the histological changes in the aorta of STZ-induced diabetic rats. Results suggested that PRF might have a beneficial effect on diabetic patients and may help to prevent the development and progression of diabetic complications such as diabetic nephropathy and atherosclerosis.

Use of Corn Silk Meal in Broiler Diet: Effect on Growth Performance, Blood Biochemistry, Immunological Responses, and Growth-Related Gene Expression

Simple Summary

Corn silk meal (CSM), the outer thread-like material found under corn husks, is a by-product of corn cultivation, which has been documented as a traditional medicine with multiple benefits for human health. Broilers cannot produce the enzymes needed to hydrolyze non-starch polysaccharide (NSP), which has been found to increase gut viscosity, and reduce the digestion and utilization of nutrients, thereby resulting in poor animal performance. The objective of this study was to examine the effects of diets supplemented with CSM and NSP on growth performance, blood biochemistry, immunological and growth-related gene expression in broiler chickens. A total of 270 broiler chickens were divided into six experimental groups: (1) basal diets (BD) as control; (2) BD supplemented with 0.5 g/kg feed NSP enzyme; (3) and (4) fed a diet containing 40 and 80 kg/ton of CSM; (5) and (6) fed a diet containing 40 and 80 kg/ton CSM and supplemented with 0.5 g/kg NSP enzyme. The results showed that the dietary inclusion of CSM with the NSP enzyme can improve growth performance, intestinal histopathology parameters, modify plasma lipids, and enhance immune response in broilers.

Abstract

The objective of this study was to examine the effects of diets supplemented with corn silk meal (CSM) and non-starch polysaccharide (NSP) enzyme on growth performance, blood biochemistry, immunological response, and growth-related gene expression in broiler chickens. A total of 270 broiler chickens were divided into six experimental groups: (1) basal diets (BD) as control; (2) BD supplemented with 0.5 g/kg feed NSP enzyme; the other four groups are CSM diets as following; (3) and (4) fed diet contain 40 and 80 kg/ton of CSM; (5) and (6) fed diet contain 40 and 80 kg/ton CSM and supplemented with 0.5 g/kg NSP enzyme. Body weight gain (BWG), feed conversion ratio (FCR), protein retention and fiber digestibility were synergistically improved (p < 0.05) when fed CSM supplemented with NSP enzyme. Moreover, a synergistic decrease (p < 0.05) in the serum glucose and total cholesterol were found. Immune organ weights and Newcastle disease virus titers were increased with CSM diets. Interestingly, the relative mRNAs of the growth hormone receptor (GHR) and insulin growth factor (IGF) were increased (p < 0.05) with the CSM and NSP enzyme: the relative mRNA expressions of cholecystokinin (CCK) and leptin were decreased by feeding CSM diets with the NSP enzyme. It could be concluded that the dietary inclusion of CSM with the NSP enzyme might improve growth performance, modify plasma lipids, and enhance immune response in broilers.

Comparison of the Flavonoid Profiles of Corn Silks to Select Efficient Varieties as Trap Plants for Helicoverpa zea

In Martinique, Helicoverpa zea is a common pest of tomato and is responsible for significant economic losses. To fight against H. zea proliferation and damage, corn could be used as a trap crop since H. zea larvae growth in the corn silk was inhibited by the presence of some flavonoids. However, only some corn varieties show an efficient inhibitory activity against H. zea depending on their flavonoid composition. In order to be able to select corn varieties with inhibition potential to be tested as a trap plant, a metabolomic approach was developed to compare the flavonoid composition of corn silks from resistant and nonresistant varieties. Quantitative analysis using UHPLC/TQ MRM MS associated with statistical treatments allowed the determination of the most concentrated and discriminant flavonoids of the resistant Java variety that clearly stood out, presenting a higher content in several C-glycosyl-O-glycosyl luteolin and apigenin derivatives such as maysin molecules.

Postprandial Glycemic and Insulinemic Effects of the Addition of Aqueous Extracts of Dried Corn Silk, Cumin Seed Powder or Tamarind Pulp, in Two Forms, Consumed with High Glycemic Index Rice

Several plant-based traditional ingredients in Asia are anecdotally used for preventing and/or treating type 2 diabetes. We investigated three such widely consumed ingredients, namely corn silk (CS), cumin (CU), and tamarind (TA). The aim of the study was to determine the effects of aqueous extracts of these ingredients consumed either as a drink (D) with high-glycemic-index rice or added to the same amount of rice during cooking (R) on postprandial glycemia (PPG), insulinemia (PPI), and blood pressure (BP), over a 3 h measurement period. Eighteen healthy Chinese men (aged 37.5 ± 12.5 years, BMI 21.8 ± 1.67 kg/m²) took part in a randomized crossover trial, each completing up to nine sessions. Compared to the control meal (plain rice + plain water), the addition of test extracts in either form did not modulate PPG, PPI, or BP. However, the extracts when added within rice while cooking gave rise to significantly lower PPI than when consumed as a drink (p < 0.01). Therefore, the form of consumption of phytochemical-rich ingredients can differentially modulate glucose homeostasis. This study also highlights the need for undertaking randomized controlled clinical trials with traditional foods/components before claims are made on their specific health effects.

Effects of β-Sitosterol from Corn Silk on TGF-β1-Induced Epithelial-Mesenchymal Transition in Lung Alveolar Epithelial Cells

Pulmonary fibrosis is a chronic lung disease characterized by abnormal accumulation of the extracellular matrix (ECM). Chronic damage of the alveolar epithelium leads to a process called "epithelial-mesenchymal transition" (EMT) and increases synthesis and deposition of ECM proteins. Therefore, inhibition of EMT might be a promising therapeutic approach for the treatment of pulmonary fibrosis. β-Sitosterol is one of the most abundant phytosterols in the plant kingdom and the major constituent in corn silk, which is derived from the stigma and style of maize (Zea mays). In this study, we elucidated that β-sitosterol inhibited transforming growth factor-β1 (TGF-β1)-induced EMT and consequently had an antifibrotic effect. β-Sitosterol (1-10 μg/mL) significantly downregulated the TGF-β1-induced fibrotic proteins, such as collagen, fibronectin, and α-smooth muscle actin in human alveolar epithelial cells (p < 0.01). After 24 h, relative wound density (RWD) was increased in TGF-β1 treated group (82.16 ± 5.70) compare to the control group (64.63 ± 2.21), but RWD was decreased in β-sitosterol cotreated group (10 μg/mL: 71.54 ± 7.39; 20 μg/mL: 65.69 ± 6.42). In addition, the changes of the TGF-β1-induced morphological shape and protein expression of EMT markers, N-cadherin, vimentin, and E-cadherin, were significantly blocked by β-sitosterol treatment (p < 0.01). The effects of β-sitosterol on EMT were found to be associated with the TGF-β1/Snail pathway, which is regulated by Smad and non-Smad signaling pathways. Taken together, these findings suggest that β-sitosterol can be used to attenuate pulmonary fibrosis through suppression of EMT by inhibiting the TGF-β1/Snail pathway.

Uric acid is a key player in salt-induced endothelial dysfunction: the therapeutic role of Stigma maydis (corn silk) extract

Hyperuricemia has been implicated in the pathogenesis and complications of cardiovascular diseases with associated elevated oxidant events. There is evidence that excessive salt intake results in cardiometabolic disturbances but the mechanism is elusive. Also, Stigma maydis (corn silk) is noted for its antioxidant properties among other beneficial roles. This study, therefore, aimed to establish the effect of high-salt diet (SD) on uric acid (UA) production and the role of S. maydis in salt-induced phenotypes. Four groups of randomly selected rats (n = 5) were fed with normal rat feed, corn silk extract (500 mg/kg), SD (8%) and corn silk extract plus high-salt feed. After 6 weeks of the experimental procedure, each animal was anesthetized by exposure to chloroform vapor and blood samples collected by cardiac puncture. Data were expressed in means ± SEM and p values <0.05 were accepted as significant. SD resulted in reduced plasma superoxide dismutase (SOD), nitric oxide (NO), and glutathione peroxidase (GPx) but not endothelial nitric oxide synthase. Also, plasma UA and vascular cell adhesion molecule-1 (VCAM-1) increased in the SD group compared with control. However, S. maydis extract in the SD-exposed group increased NO and GPx and not SOD. Also, S. maydis extract attenuated UA and VCAM-1. In conclusion, high-salt intake may initiate deleterious cardiovascular events through UA-dependent mechanism and S. maydis extract has therapeutic potential in high-salt-induced oxidative damage and/or UA-dependent endothelial pathologies.

Antihypertensive Effects of Corn Silk Extract and Its Novel Bioactive Constituent in Spontaneously Hypertensive Rats: The Involvement of Angiotensin-Converting Enzyme Inhibition

Corn silk tea has been used in folk medicine for anti-hypertensive healthcare. Angiotensin-converting enzyme (ACE) plays a crucial role on the homeostasis of blood pressure. However, effects of corn silk tea on ACE activity and the presence of ACE inhibitory constituents in corn silk are still unknown. Here we applied proteomics and bioinformatics approaches to identify corn silk bioactive peptides (CSBps) that target ACE from the boiling water extract of corn silk (CSE). CSE significantly reduced systolic blood pressure (SBP) levels in spontaneously hypertensive rats and inhibited the ACE activity. By proteomics coupled with bioinformatics analyses, we identified a novel ACE inhibitory peptide CSBp5 in CSE. CSBp5 significantly inhibited the ACE activity and decreased SBP levels in a dose-dependent manner. Docking analysis showed that CSBp5 occupied the substrate-binding channel of ACE and interacted with ACE via hydrogen bonds. In conclusion, we identified that CSE exhibited anti-hypertensive effects in SHRs via the inhibition of ACE, the target of most anti-hypertensive drugs. In addition, an ACE inhibitory phytopeptide CSBp5 that decreased SBP levels in rats was newly identified. Our findings supported the ethnomedical use of corn silk tea on hypertension. Moreover, the identification of ACE inhibitory phytopeptide in corn silk further strengthened our findings.

Rapid discovery and global characterization of multiple components in corn silk using a multivariate data processing approach based on UHPLC coupled with electrospray ionization/quadrupole time-of-flight mass spectrometry

Corn silk is an important traditional Chinese medicine which has been widely used as diuretic, antilithiasic, uricosuric, antiseptic, etc. for thousands of years. However, it is a pity that the chemical ingredients in corn silk, especially the constituents absorbed into blood, are unclear up to now. The aim of our study was to investigate the multiple components of corn silk in vitro and in vivo. In this present study, a sensitive and rapid method using ultra high performance liquid chromatography coupled with electrospray ionization/quadrupole time-of-flight tandem mass spectrometry and a multivariate data processing approach was established to detect the constituents of corn silk in vitro and in vivo. Consequently, total 41 ingredients in vitro and 19 of them absorbed into blood including luteolin, various C-glycosyl flavones, jasmonic acid, abscisic acid, gibberellin A, etc. were tentatively characterized in sequence. Furthermore, of particular importance, a kind of stable compound named C-glycosyl flavones is a great discovery in vivo, which can point the further pharmacological study target in future. In a word, this is the first serum pharmacochemistry study of corn silk, which played a critical role in exploring the pharmacological and effective data for further research.

Acute and Subacute Toxicity Evaluation of Corn Silk Extract

Many studies have reported therapeutic efficacy of corn silk extract. However, research on its toxicity and safe dose range is limited. Thus, the objective of this study was to determine the acute and subacute toxicity of corn silk extract in ICR mice. To determine acute toxicity, corn silk extract containing high levels of maysin was orally administered to mice at a dose of 0 or 2,000 mg/kg. Clinical symptoms, mortality, and body weight changes were recorded for 14 days. To determine subacute toxicity, corn silk extract was orally administered to mice over a 4-week period, and then body weight, water and food consumption, and organ weight were determined. In addition, urine and serum analyses were performed. In the acute toxicity study, no death or abnormal symptoms was observed in all treatment groups during the study period. Body weights did not show any significant change compared to those of the control group. Lethal dose of corn silk extract was estimated to be more than 2,000 mg/kg. In the 4-week subacute toxicity study, there was no corn silk extract related toxic effect on body weight, water intake, food consumption, urine parameters, clinical chemistry, or organ weight. Histopathological examination showed no abnormality related to the administration of corn silk extract at 500 mg/kg. The maximum non-toxic dose of corn silk extract containing high levels of maysin was found to be more than 500 mg/kg.

Corn Silk Extract and Its Bioactive Peptide Ameliorated Lipopolysaccharide-Induced Inflammation in Mice via the Nuclear Factor-κB Signaling Pathway

Bioactive peptides derived from foods have shown beneficial anti-inflammatory potential. Inhibitory κB kinase-β (IKKβ) plays a crucial role in the activation of nuclear factor-κB (NF-κB), a transcription factor involved in inflammation. Here we applied proteomic and bioinformatics approaches to identify anti-inflammatory peptides that target IKKβ from corn silk. Corn silk extract significantly suppressed lipopolysaccharide (LPS)-induced NF-κB activities [(1.7 ± 0.2)-fold vs (3.0 ± 0.6)-fold, p < 0.05] in cells. Trypsin hydrolysate of corn silk also suppressed LPS-induced NF-κB activities [(1.1 ± 0.3)-fold vs 3.3 ± 0.5 fold, p < 0.01]. In addition, both corn silk extract and trypsin hydrolysate significantly inhibited LPS-induced interleukin-1β (IL-1β) production by 58.3 ± 4.5 and 55.1 ± 7.4%, respectively. A novel peptide, FK2, docked into the ATP-binding pocket of IKKβ, was further identified from trypsin hydrolysis of corn silk. FK2 inhibited IKKβ activities, IκB phosphorylation, and subsequent NF-κB activation [(2.3 ± 0.4)-fold vs (5.5 ± 0.4)-fold, p < 0.001]. Moreover, FK2 significantly reduced NF-κB-driven luminescent signals in organs by 5-11-fold and suppressed LPS-induced NF-κB activities and IL-β production in tissues. In conclusion, our findings indicated that corn silk displayed anti-inflammatory abilities. In addition, we first identified an anti-inflammatory peptide FK2 from corn silk. Moreover, the anti-inflammatory effect of FK2 might be through IKKβ-NF-κB signaling pathways.

Pro-apoptotic and anti-proliferative effects of corn silk extract on human colon cancer cell lines

Corn silk is an economically and nutritionally significant natural product as it represents a staple food for a large proportion of the world population. This study investigated the anticancer activity of corn silk extract in human colon cancer cells and human gastric cancer cells. Following treatment with corn silk extract, certain apoptosis-related events were observed, including inhibition of cell proliferation, loss of mitochondrial membrane potential (ΔΨm), release of Ca2+ and release of cytochrome c from the mitochondria into the cytosol. Our results revealed that corn silk extract inhibited the proliferation of cancer cells and increased the level of apoptosis in a concentration-dependent manner. Western blot analysis revealed that corn silk extract upregulated the levels of Bax, cytochrome c, caspase-3 and caspase-9, but downregulated the levels of B-cell lymphoma 2. These results suggest that corn silk extract may induce apoptosis through the mitochondria-mediated pathway.

Anti-Diabetic, Anti-Oxidant and Anti-Hyperlipidemic Activities of Flavonoids from Corn Silk on STZ-Induced Diabetic Mice

Corn silk is a well-known ingredient frequently used in traditional Chinese herbal medicines. This study was designed to evaluate the anti-diabetic, anti-oxidant and anti-hyperlipidemic activities of crude flavonoids extracted from corn silk (CSFs) on streptozotocin (STZ)-induced diabetic mice. The results revealed that treatment with 300 mg/kg or 500 mg/kg of CSFs significantly reduced the body weight loss, water consumption, and especially the blood glucose (BG) concentration of diabetic mice, which indicated their potential anti-diabetic activities. Serum total superoxide dismutase (SOD) and malondialdehyde (MDA) assays were also performed to evaluate the anti-oxidant effects. Besides, several serum lipid values including total cholesterol (TC), triacylglycerol (TG), low density lipoprotein cholesterol (LDL-C) were reduced and the high density lipoprotein cholesterol level (HDL-C) was increased. The anti-diabetic, anti-oxidant and anti-hyperlipidemic effect of the CSFs suggest a potential therapeutic treatment for diabetic conditions.