Protective effects of corn silk extract administration on gentamicin-induced nephrotoxicity in rat

Recent Advances in the Extraction and Characterization of Bioactive Compounds from Corn By-Products

Maize comes in a variety of colors, including white, yellow, red, blue, and purple, which is due to the presence of phytochemicals such as carotenoids, anthocyanins, flavonoids, phytosterols, and some hydroxycinnamic acid derivatives. In Mexico, maize is primarily grown for human consumption; however, maize residues comprise 51-58% of the total maize plant weight (stalks, leaves, ears, and husks) and are mainly used as livestock feed. These residues contain numerous bioactive compounds that interest the industry for their potential health benefits in preventing or treating degenerative diseases. This review explores the current knowledge and highlights key aspects related to the extraction methods and different techniques for identifying the bioactive compounds found in maize by-products.

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.

By-Products of Zea mays L.: A Promising Source of Medicinal Properties with Phytochemistry and Pharmacological Activities: A Comprehensive Review

Zea mays (Z. mays) is one of the main cereal crops in the world, and it's by-products have exhibited medicinal properties to explore. This article intends to review the chemical compositions and pharmacological activities of by-products of Z. mays (corn silks, roots, bract, stems, bran, and leaves) which support the therapeutic potential in the treatment of different diseases, with emphasis on the natural occurring compounds and detailed pharmacological developments. Based on this review, 231 natural compounds are presented. Among them, flavonoids, terpenes, phenylpropanoids, and alkaloids are the most frequently reported. The by-products of Z. mays possess diuretic effects, hepatoprotective, anti-diabetic, antioxidant, neuroprotective, anti-inflammatory, anti-cancer, plant protection activity, and other activities. This article reviewed the phytochemistry and pharmacological activities of Z. mays for comprehensive quality control and the safety and effectiveness to enhance future application.

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.

Evaluation of symmetric dimethylarginine and Doppler ultrasonography in the diagnosis of gentamicin-induced acute kidney injury in dogs

Acute kidney injury is a common problem in dogs and is associated with significant morbidity and mortality. So, the present study aimed to evaluate symmetric dimethylarginine (SDMA) and Doppler ultrasonography including resistive index (RI) in the diagnosis of acute kidney injury in dogs. Ten healthy mongrel dogs were injected with gentamicin sulfate 10% at the dose of 30 mg/kg body weight daily for 10 days for induction of acute kidney injury. Clinical, biochemical, ultrasonographic, and Doppler ultrasonographic examinations and urinalysis were performed for all dogs on 0 day before induction, on the 5th day, and on the 10th day of induction. The results of the current study showed significant increase in plasma level of SDMA, serum urea, creatinine, phosphorus, and potassium and a significant decrease in serum sodium, calcium, and chloride on the 5th day and 10th day of induction, and there was an increase in renal cortical echogenicity of the right and left kidney compared to adjacent liver and spleen, respectively. RI value showed a significant increase on the 5th day and 10th day of induction. The present study showed that SDMA is a sensitive and promising biomarker for diagnosis of acute kidney injury in dogs compared to routine biomarkers; also, the RI of Doppler ultrasonography is useful for early identifying acute kidney injury when the only observable change is an increase in cortical echogenicity.

Ameliorative effects of corn silk extract on acetaminophen-induced renal toxicity in rats

The current study aimed to investigate the protective effect of corn silk methanolic extract (CSME) against acetaminophen (APAP)-induced nephrotoxicity. The present study was carried out on 40 male Wistar albino rats, which were randomly divided into four groups (n = 10): control group, orally administered with a single dose of 1.8 ml 0.9% normal saline at the last day of the experiment; CSME group, orally received CSME (400 mg/kg BW daily for 5 weeks); APAP group, orally administered with a single dose of APAP (2 g/kg BW); and CSME and APAP group, orally administered with CSME, followed by a single oral dose of APAP. The results of this study revealed that APAP caused a significant increase in serum urea, creatinine concentrations, and malondialdehyde (MDA) concentrations in renal tissues. In addition, APAP caused a significant decrease in superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities in renal tissues compared with the control group. Furthermore, APAP caused marked renal damage as revealed by alterations in histopathological architectures of kidney tissues. APAP resulted in a marked expression of caspase 3 and nuclear factor κB (NFĸβ) within the renal tubules, while caused marked decrease of proliferating cell nuclear antigen (PCNA) immunostaining and transforming growth factor beta 1 (TGFβ 1) expression within the epithelial lining of the renal tubules. However, pre-treatment with CSME returned all biochemical parameters, histopathological changes, and immunohistochemical parameters toward normal levels as the control group. In conclusion, oral administration of CSME protected rats against APAP renal toxicity through its antioxidant, anti-apoptotic, and anti-inflammatory protective mechanisms.

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.

Corn silk (Zea mays L.), a source of natural antioxidants with α-amylase, α-glucosidase, advanced glycation and diabetic nephropathy inhibitory activities

The oxidative stress plays a critical role in the progression of diabetes mellitus (DM) and its complications. Corn silk is a traditional medicine used to treat DM. The aim of this study is to investigate the antioxidant capacity of corn silk, as well as its inhibitory potential on DM and diabetic nephropathy (DN). The ethanol extract of corn silk (CS) was liquid-liquid fractionated to get petroleum ether fraction (PCS), ethyl acetate fraction (ECS), n-butanol fraction (BCS) and water fraction (WCS). The Folin-Ciocalteu and AlCl₃ assay showed that silk corn contained considerable amount of phenolics and flavonoids, ECS and BCS were the two phenolic-enriched fractions with highest TPC and TFC values. The ECS and BCS showed the highest total antioxidant activity and reducing power, as well as the strongest scavenging activity against DPPH and hydroxyl radicals, compared to CS and other fractions. The ECS and BCS displayed appreciable anti-hyperglycaemic effect indicated by the significant inhibition on α-amylase and α-glucosidase in enzymatic assays. In BSA-glucose model, ECS and BCS effectively inhibited the formation of advanced glycation end products (AGEs). In addition, the anti-diabetic nephropathy activity assay displayed that CS, ECS and BCS significantly inhibited the production of Col IV, FN and IL-6 in high-glucose stimulated mesangial cells at 200 μg/mL. These findings suggested the antioxidant activities of corn silk could contribute, at least in part, to its traditionally claimed therapeutic benefits on DM and DN. The phenolic-enriched CS fractions could be considered as a source of natural antioxidants and further developed for the prevention and treatment of DM and its complications including DN.

Membrane Stabilization and Detoxification of Acetaminophen-Mediated Oxidative Onslaughts in the Kidneys of Wistar Rats by Standardized Fraction of Zea mays L. (Poaceae), Stigma maydis

This study evaluated membrane stabilization and detoxification potential of ethyl acetate fraction of Zea mays L., Stigma maydis in acetaminophen-induced oxidative onslaughts in the kidneys of Wistar rats. Nephrotoxic rats were orally pre- and posttreated with the fraction and vitamin C for 14 days. Kidney function, antioxidative and histological analyses were thereafter evaluated. The acetaminophen-mediated significant elevations in the serum concentrations of creatinine, urea, uric acid, sodium, potassium, and tissue levels of oxidized glutathione, protein-oxidized products, lipid peroxidized products, and fragmented DNA were dose-dependently assuaged in the fraction-treated animals. The fraction also markedly improved creatinine clearance rate, glutathione, and calcium concentrations as well as activities of superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase in the nephrotoxic rats. These improvements may be attributed to the antioxidative and membrane stabilization activities of the fraction. The observed effects compared favorably with that of vitamin C and are informative of the fraction's ability to prevent progression of renal pathological conditions and preserve kidney functions as evidently supported by the histological analysis. Although the effects were prominently exhibited in the fraction-pretreated groups, the overall data from the present findings suggest that the fraction could prevent or extenuate acetaminophen-mediated oxidative renal damage via fortification of antioxidant defense mechanisms.

Corn silk (Stigma maydis) in healthcare: a phytochemical and pharmacological review

Corn silk (Stigma maydis) is an important herb used traditionally by the Chinese, and Native Americans to treat many diseases. It is also used as traditional medicine in many parts of the world such as Turkey, United States and France. Its potential antioxidant and healthcare applications as diuretic agent, in hyperglycemia reduction, as anti-depressant and anti-fatigue use have been claimed in several reports. Other uses of corn silk include teas and supplements to treat urinary related problems. The potential use is very much related to its properties and mechanism of action of its plant's bioactive constituents such as flavonoids and terpenoids. As such, this review will cover the research findings on the potential applications of corn silk in healthcare which include its phytochemical and pharmacological activities. In addition, the botanical description and its toxicological studies are also included.