High maysin corn silk extract reduces body weight and fat deposition in C57BL/6J mice fed high-fat diets

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.

Lemon Balm and Corn Silk Mixture Alleviates Metabolic Disorders Caused by a High-Fat Diet

We recently reported that varying combination ratios of lemon balm (Mellissa officinalis L.) and corn silk extracts (Stigma of Zea mays L. fruit) could reduce the obesity caused by a high-fat diet (HFD). The present study investigated the dose-dependent effect of a 1:1 (w:w) mixture of lemon balm and corn silk extracts (M-LB/CS) on HFD-mediated metabolic disorders and compared the effect with metformin. Oral administration of 50–200 mg/kg of M-LB/CS for 84 days significantly inhibited HFD-induced body weight gain, adipocyte hypertrophy, and lipogenic gene induction without affecting food consumption in mice. Biochemical analyses showed that M-LB/CS blocked abnormal lipid accumulation in the blood by escalating fecal lipid excretion. In addition, M-LB/CS prevented HFD-mediated pancreatic atrophy, decreased the number of insulin- and glucagon-immunoreactive cells, and inhibited increases in glycated hemoglobin, glucose, and insulin. Moreover, M-LB/CS also reduced hepatic injury, lipid accumulation, gluconeogenesis, and lipid peroxidation in parallel with the induction of AMP-activated protein kinase and antioxidant enzymes. Furthermore, M-LB/CS protected the kidney by inhibiting tubular vacuolation and reducing serum creatinine and blood urea nitrogen levels. The prophylactic effect of 100 mg/kg M-LB/CS-administration was comparable to that of metformin. Therefore, M-LB/CS may be an alternative option for managing obesity and its related metabolic disorders.

Lemon Balm and Corn Silk Extracts Mitigate High-Fat Diet-Induced Obesity in Mice

Lemon balm and corn silk are valuable medicinal herbs, which exhibit variety of beneficial effects for human health. The present study explored the anti-obesity effects of a mixture of lemon balm and corn silk extracts (M-LB/CS) by comparison with the effects of single herbal extracts in high-fat diet (HFD)-induced obesity in mice. HFD supplementation for 84 days increased the body weight, the fat mass density, the mean diameter of adipocytes, and the thickness of fat pads. However, oral administration of M-LB/CS significantly alleviated the HFD-mediated weight gain and adipocyte hypertrophy without affecting food consumption. Of the various combination ratios of M-LB/CS tested, the magnitude of the decreases in weight gain and adipocyte hypertrophy by administration of 1:1, 1:2, 2:1, and 4:1 (w/w) M-LB/CS was more potent than that by single herbal extracts alone. In addition, M-LB/CS reduced the HFD-mediated increases in serum cholesterol, triglyceride, and low-density lipoprotein, prevented the reduction in serum high-density lipoprotein, and facilitated fecal excretion of cholesterol and triglyceride. Moreover, M-LB/CS mitigated the abnormal changes in specific mRNAs associated with lipogenesis and lipolysis in the adipose tissue. Furthermore, M-LB/CS reduced lipid peroxidation by inhibiting the HFD-mediated reduction in glutathione, catalase, and superoxide dismutase. Therefore, M-LB/CS is a promising herbal mixture for preventing obesity.

Optimization and Encapsulation of Phenolic Compounds Extracted from Maize Waste by Freeze-Drying, Spray-Drying, and Microwave-Drying Using Maltodextrin

Cornsilk is maize waste containing phenolic compounds. In this study, freeze-drying, spray-drying, and microwave-drying techniques were evaluated for the encapsulation of cornsilk's phenolic compounds using maltodextrin as wall material. The results of antioxidant properties showed that freeze-drying was more efficient than microwave-drying and spray-drying techniques. The highest recovery of phenolic compounds was obtained with freeze-drying. The microstructure, DSC, and FTIR data showed that the encapsulation process was effective, and freeze-drying was the best drying technique. The physical properties of the microparticles greatly changed with the drying techniques. This study revealed that the phenolic compounds of the cornsilk extract can be successfully encapsulated and valorized.

Maysin plays a protective role against α-Synuclein oligomers cytotoxicity by triggering autophagy activation

Parkinson's disease (PD) is a widespread neurodegenerative disorder characterized by the progressive loss of neurons. The accumulation of aggregated forms of the α-Synuclein (Syn) protein is the main cause of neurotoxicity in PD by disrupting cellular homeostasis until neuronal death. Scientific research is constantly looking for natural products as preventive agents against the progression of several neurodisorders due their safety and non-toxic nature. Neuroprotective phytochemicals include Maysin (Mys), the most abundant C-glycosilflavone in corn silk. In this work, the Mys protective role against damage by Syn amyloid aggregates - oligomers and fibrils - was investigated in SH-SY5Y human neuroblastoma cells obtaining novel and interesting information concerning the Mys molecular mechanism of action. Mys showed effectiveness in preventing the typical toxic events induced by Syn amyloid aggregates, i.e. oxidative stress and imbalance of intracellular calcium homeostasis. Mys exhibited a cytoprotective role, especially against Syn oligomers injury, activating an autophagic degradative process, thus playing a key role on several features of amyloid neurotoxicity. Therefore, Mys could be proposed for the first time to the scientific community as an interesting novel natural compound that might allow to develop alternative strategies to prevent the damage of Syn oligomers involved in Parkinson's disease.

Corn Silk (Zea mays L.) Induced Apoptosis in Human Breast Cancer (MCF-7) Cells via the ROS-Mediated Mitochondrial Pathway

Cancer has been recognized as one of the life-threating diseases. Breast cancer is a leading cause of mortality among women. In spite of current developments in the therapy and diagnosis of cancer, the survival rate is still less. Recently, plant-derived natural products gain attention as anticancer agents due to the nontoxic nature. Therefore, the aim of present study was to investigate the anticancer capacity of corn silk extract (CSE) on human breast cancer (MCF-7) and normal human mesenchymal (hMSC-TERT4) cells. Following 24 h treatment to corn silk extract, the cytotoxicity was assessed by MTT, NRU, and morphological assays. The oxidative stress markers (GSH and LPO), ROS production, MMP change, and expression of apoptotic marker genes (p53, Bax, Bcl-2, caspase-3, and caspase-9) were also studied in MCF-7 cells treated at 250 to 1000 μg/ml of CSE for 24 h. Our results showed that CSE decreased the cell viability and increased the apoptosis in a dose-dependent manner. The level of LPO and ROS production was found significantly higher; however, GSH and MMP level was observed lower in CSE-treated MCF-7 cells. The real-time PCR data showed a significant upregulation in p53, Bax, caspase-3, and caspase-9 and downregulation in the mRNA expression of Bcl-2 genes in MCF-7 cells exposed to CSE. Collectively, the data from this study stated that corn silk extract induced apoptosis via the ROS-mediated mitochondrial pathway in MCF-7 cells.

Inhibitory effect of saccharides and phenolic compounds from maize silks on intestinal α-glucosidases

Maize silks have been used in Mexico for centuries as a natural-based treatment for various illnesses, including obesity and diabetes. It has been shown in mice that intake of maize silk extracts reduces the levels of blood glucose. However, it is not clear how or what maize silk compounds are involved in such an effect. A hypothesized mechanism is that some maize silk compounds can inhibit carbohydrate hydrolyzing enzymes like α-glucosidases. This work aimed to assess the capability of both saccharides and phenolic compounds from maize silks to inhibit intestinal α-glucosidases. Results showed that saccharides from maize silks did not produce inhibition on intestinal α-glucosidases, but phenolics did. Maize silk phenolics increased the value of K_m significantly and decreased the V_max slightly, indicating a mixed inhibition of α-glucosidases. According to the molecular docking analysis, the phenolics maysin, methoxymaysin, and apimaysin, which had the highest predicted binding energies, could be responsible for the inhibition of α-glucosidases. PRACTICAL APPLICATIONS: The International Diabetes Federation (IDF) reported in 2017 that diabetes affects over 424 million people worldwide, and caused 4 million deaths. Non-insulin-dependent diabetes or type 2 diabetes mellitus (T2DM) accounts for ∼90% of cases. T2DM is characterized by insulin resistance and pancreatic β-cell failure. Therapy for T2DM includes the use of sulfonylureas, thiazolidinediones, biguanides, and α-glucosidase inhibitors. Regarding the α-glucosidase inhibitors, only few are commercially available, and these have been associated with severe gastrointestinal side effects. This work aimed to assess the capability of both saccharides and phenolic compounds from maize silks to inhibit intestinal α-glucosidases. Results from this work evidenced that maize silk polyphenols acted as effective inhibitors of intestinal rat α-glucosidases. Computational analysis of maize silk polyphenols indicated that maysin, a particular flavonoid from maize silks, could be responsible for the inhibition of α-glucosidases.

Distribution of Four Bioactive Flavonoids in Maize Tissues of Five Varieties and Correlation with Expression of the Biosynthetic Genes

Flavonoids are characteristic in maize and have diverse biological functions. C-Glycosylflavones are neuroprotective against β-amyloid-induced tau hyperphosphorylation and neurotoxicity in SH-SY5Y cells, which is relevant to Alzheimer's disease prevention and treatment. The content of the flavonoids eriodictyol, luteolin, isoorientin, and maysin varied in pollens, silks, tassels, and seeds among five maize varieties. Eriodictyol content was high (51-322 ng/g dw) in pollens, while luteolin content was low (0.2-106 ng/g dw) in all four tissues. The isoorientin content was approximately 3- to 10-fold greater than eriodictyol in pollens and tassels, particularly in the hybrid M1 and sweet corn M5 varieties. Maysin content was high in most silks and tassels. The differential expression of five genes involved in the maysin biosynthesis correlated well with the profiles of the four flavonoids among tissues and varieties. The present study offers valuable data for maize breeding and the use of maize flavonoids as functional food components.

Galectin-12 is Involved in Corn Silk-Induced Anti-Adipogenesis and Anti-Obesity Effects

Obesity is a significant risk factor for various diseases. It is a clinical condition caused by the excessive accumulation of fat, which has a negative impact on human health. Galactin-12 is an adipocyte-expressed protein and possesses adipocyte-inducing activity. We investigated the expression level of candidate proteins involved in galactin-12-mediated adipocyte differentiation pathway. We performed a high-throughput screening assay to monitor galectin-12 promoter activity using 105 traditional Chinese herbs. Corn silk extract and [Formula: see text]-sitosterol reduced the expression of galactin-12 promoter in 3T3-L1 cells. In addition, corn silk extract and [Formula: see text]-sitosterol decreased the level of lipid droplets and downregulated the gene and protein expression level of C/EBP[Formula: see text], C/EBP[Formula: see text], PPAR[Formula: see text], Ap2, and adipsin in 3T3-L1 pre-adipocytes via AKT and ERK1/2 inhibition. In vivo study with the oral administration of corn silk extract and [Formula: see text]-sitosterol in a mouse model showed a significant weight reduction and decrease in adipocytes in several organs such as the liver and adipose tissue. Taken together, corn silk extract and [Formula: see text]-sitosterol may effectively reduce pre-adipocyte differentiation by inhibiting galectin-12 activity and exerting anti-obesity effects. These findings highlight the potential use of corn silk extract and [Formula: see text]-sitosterol as potential candidates for the prevention and treatment of obesity.

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 improves benign prostatic hyperplasia in experimental rat model

BACKGROUND/OBJECTIVES

This study was conducted to investigate the effect of a corn silk extract on improving benign prostatic hyperplasia (BPH).

MATERIALS/METHODS

The experimental animals, 6-week-old male Wistar rats, were divided into sham-operated control (Sham) and experimental groups. The experimental group, which underwent orchiectomy and received subcutaneous injection of 10 mg/kg of testosterone propionate to induce BPH, was divided into a Testo Only group that received only testosterone, a Testo+Fina group that received testosterone and 5 mg/kg finasteride, a Testo+CSE10 group that received testosterone and 10 mg/kg of corn silk extract, and a Testo+CSE100 group that received testosterone and 100 mg/kg of corn silk extract. Prostate weight and concentrations of dihydrotestosterone (DHT), 5α-reductase 2 (5α-R2), and prostate specific antigen (PSA) in serum or prostate tissue were determined. The mRNA expressions of 5α-R2 and proliferating cell nuclear antigen (PCNA) in prostate tissue were also measured.

RESULTS

Compared to the Sham group, prostate weight was significantly higher in the Testo Only group and decreased significantly in the Testo+Fina, Testo+CSE10, and Testo+CSE100 groups (P < 0.05), results that were consistent with those for serum DHT concentrations. The concentrations of 5α-R2 in serum and prostate as well as the mRNA expression of 5α-R2 in prostate were significantly lower in the Testo+Fina, Testo+CSE10, and Testo+CSE100 groups than that in the Testo Only group (P < 0.05). Similarly, the concentrations of PSA in serum and prostate were significantly lower in the Testo+Fina, Testo+CSE10, and Testo+CSE100 groups (P < 0.05) than in the Testo Only group. The mRNA expression of PCNA in prostate dose-independently decreased in the Testo+CSE-treated groups (P < 0.05).

CONCLUSIONS

BPH was induced through injection of testosterone, and corn silk extract treatment improved BPH symptoms by inhibiting the mRNA expression of 5α-R2 and decreasing the amount of 5α-R2, DHT, and PSA in serum and prostate tissue.