Anti-inflammation effects of corn silk in a rat model of carrageenin-induced pleurisy

Elucidation of active components and target mechanism in Jinqiancao granules for the treatment of prostatitis and benign prostatic hyperplasia

ETHNOPHARMACOLOGICAL RELEVANCE

Prostatitis and benign prostatic hyperplasia (BPH) are inflammations of the prostate gland, which surrounds the urethra in males. Jinqiancao granules are a traditional Chinese medicine used to treat kidney stones and this medicine consists of four herbs: Desmodium styracifolium (Osbeck) Merr., Pyrrosia calvata (Baker) Ching, Plantago asiatica L. and stigma of Zea mays L.

AIM OF THE STUDY

We hypothesized that Jinqiancao granules could be a potential therapy for prostatitis and BPH, and this work aimed to elucidate active compounds in Jinqiancao granules and their target mechanisms for the potential treatment of the two diseases.

MATERIALS AND METHODS

Jinqiancao granules were commercially available and purchased. Database-driven data mining and networking were utilized to establish a general correlation between Jinqiancao granules and the two diseases above. Ultra-performance liquid chromatography-mass spectrometry was used for compound separation and characterization. The characterized compounds were evaluated on four G-protein coupled receptors (GPCRs: GPR35, muscarinic acetylcholine receptor M3, alpha-1A adrenergic receptor α1A and cannabinoid receptor CB2). A dynamic mass redistribution technique was applied to evaluate compounds on four GPCRs. Nitric acid (NO) inhibition was tested on the macrophage cell line RAW264.7. Molecular docking was conducted on GPR35-active compounds and GPR35 crystal structure. Statistical analysis using GEO datasets was conducted.

RESULTS

Seventy compounds were isolated and twelve showed GPCR activity. Three compounds showed potent GPR35 agonistic activity (EC50 < 10 μM) and the GPR35 agonism action of PAL-21 (Scutellarein) was reported for the first time. Docking results revealed that the GPR35-targeting compounds interacted at the key residues for the agonist-initiated activation of GPR35. Five compounds showed weak antagonistic activity on M3, which was confirmed to be a disease target by statistical analysis. Seventeen compounds showed NO inhibitory activity. Several compounds showed multi-target properties. An experiment-based network reflected a pharmacological relationship between Jinqiancao granules and the two diseases.

CONCLUSIONS

This study identified active compounds in Jinqiancao granules that have synergistic mechanisms, contributing to anti-inflammatory effects. The findings provide scientific evidence for the potential use of Jinqiancao granules as a treatment for prostatitis and BPH.

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.

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.

Novel Therapeutics for Treating Sleep Disorders: New Perspectives on Maydis stigma

Sleep is a restorative period that plays a crucial role in the physiological functioning of the body, including that of the immune system, memory processing, and cognition. Sleep disturbances can be caused by various physical, mental, and social problems. Recently, there has been growing interest in sleep. Maydis stigma (MS, corn silk) is a female maize flower that is traditionally used as a medicinal plant to treat many diseases, including hypertension, edema, and diabetes. It is also used as a functional food in tea and other supplements. β-Sitosterol (BS) is a phytosterol and a natural micronutrient in higher plants, and it has a similar structure to cholesterol. It is a major component of MS and has anti-inflammatory, antidepressive, and sedative effects. However, the potential effects of MS on sleep regulation remain unclear. Here, we investigated the effects of MS on sleep in mice. The effects of MS on sleep induction were determined using pentobarbital-induced sleep and caffeine-induced sleep disruption mouse models. MS extracts decreased sleep latency and increased sleep duration in both the pentobarbital-induced sleep induction and caffeine-induced sleep disruption models compared to the positive control, valerian root extract. The butanol fraction of MS extracts decreased sleep latency time and increased sleep duration. In addition, β-sitosterol enhances sleep latency and sleep duration. Both MS extract and β-sitosterol increased alpha activity in the EEG analysis. We measured the mRNA expression of melatonin receptors 1 and 2 (MT1/2) using qRT-PCR. The mRNA expression of melatonin receptors 1 and 2 was increased by MS extract and β-sitosterol treatment in rat primary cultured neurons and the brain. In addition, MS extract increased the expression of clock genes including per1/2, cry1/2, and Bmal1 in the brain. MS extract and β-sitosterol increased the phosphorylation of ERK1/2 and αCaMKII. Our results demonstrate for the first time that MS has a sleep-promoting effect via melatonin receptor expression, which may provide new scientific evidence for its use as a potential therapeutic agent for the treatment and prevention of sleep disturbance.

Undescribed C-Glycosylflavones from Corn Silk and Potential Anti-inflammatory Activity Evaluation of Isolates

Phytochemical investigation of corn silk resulted in isolation and characterization of four flavone C-glycosides, chrysoeriol 6-C-β-oliopyranosyl-7-O-β-D-glucopyranoside (1: ), 3'-methoxycassiaoccidentalin A (2: ), chrysoeriol 6-C-β-boivinopyranosyl-7-O-β-D-glucopyranoside (3: ), and ax-4″-OH-3'-methoxymaysin (4: ), a triterpenoid, friedelin (5: ), two sterols, (22E)-5α,8α-epidioxyergosta-6,22-dien-3β-ol (6: ) and 6β-hydroxystigmasta-4,22-diene-3-one (7: ), and a mixture of β-sitosterol and stigmasterol. Compounds 1: and 2: were previously undescribed. Structure elucidation of the isolated compounds was attained using spectral data including 1D and 2D NMR and HRESIMS. Compounds1, 2, 5: , and 6: inhibited iNOS activity in LPS-induced macrophages and decreased nitrite levels by 68.64 ± 4.46, 65.67 ± 6.47, 88.50 ± 0.50, and 94.00 ± 4.00%, respectively, at 50 µM. Compound 5: also showed inhibition of NF-κB (51.00 ± 1.50%). Compounds 1: and 2: induced NAG-1 activity in chondrocytes by 1.80 ± 0.05 and 2.00 ± 0.13 fold, respectively. The extract of corn silk, however, did not exhibit inhibition of iNOS or NF-κB but induced NAG-1 by 1.80 ± 0.51 fold.

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.

Antioxidant, Anti-Inflammatory, and Anti-Apoptotic Effects of Azolla pinnata Ethanolic Extract against Lead-Induced Hepatotoxicity in Rats

The current study investigated the protective potential of Azolla pinnate ethanolic extract (APE) against lead-induced hepatotoxicity in rats. Sixty male Wistar albino rats were randomly allocated into six groups (n = 10). The control group was orally administrated with saline. The second group received lead acetate (100 mg/kg body weight (BW) orally for 60 days). The third group was fed with APE (10 mg/kg BW orally for 60 days). The fourth group was administrated with lead acetate like the second group and APE like the third group, concomitantly, for 60 days. The fifth group was administrated with APE like the third group for 30 days, then orally administrated with the lead acetate like the second group for another 30 days. The sixth group was administrated with lead acetate like the second group for 30 days, then with APE like the third group for a further 30 days. Phytochemical analysis of APE indicated the presence of peonidin 3-O-glucoside cation, vitexin, rutin, thiamine, choline, tamarixetin, hyperoside, astragalin, and quercetin. The latter has been elucidated using one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) and liquid chromatography–mass spectrometry (LC–MS-MS). Lead acetate increased the serum levels of alanine and aspartate aminotransferases and that of urea, creatinine, tumor necrosis factor alpha, and interleukin 1β, hepatic tissue malondialdehyde contents, and caspase 3 protein expression, as well as altering the hepatic tissue architecture. However, it decreased the serum levels of interleukin 10 and glutathione (GSH) contents, and the activities of catalase and superoxide dismutase in hepatic tissue. In contrast, the administration of APE ameliorated the lead-induced alterations in liver function and structure, exemplifying the benefits of Azolla’s phytochemical contents. Collectively, A. pinnate extract is a protective and curative agent against lead-induced hepatotoxicity via its antioxidant, anti-inflammatory, and anti-apoptotic impacts.

Natural therapeutics for urinary tract infections-a review

Background

The recurrence of the urinary tract infections (UTI), following the antibiotic treatments suggests the pathogen’s resistance to conventional antibiotics. This calls for the exploration of an alternative therapy.

Main body

The anti-uropathogenic and bactericidal activity of many plant extracts was reported by many researchers, which involves only preliminary antibacterial studies using different basic techniques like disk diffusion, agar well diffusion, or minimum inhibitory concentration (MIC) of the crude plant extracts, but reports on the specific action of the phytoconstituents against uropathogens are limited. Vaccinium macrocarpon Aiton (cranberry) is the best-studied home remedy for UTI. Some evidences suggest that proanthocyanins present in cranberry, prevent bacteria from adhering to the walls of the urinary tract, subsequently blocking the further steps of uropathogenesis. Probiotics such as Lactobacillus and Bifidobacterium are beneficial microorganisms that may act by the competitive exclusion principle to defend against infections in the urogenital tracts. Reports on potential vaccine agents and antibodies targeting the different toxins and effecter proteins are still obscure except uropathogenic E. coli.

Conclusion

This review highlights some of the medicinal herbs used by aborigines to prevent or treat acute or chronic urinary tract infections, botanicals with established urobactericidal activity, clinical trials undertaken to compare the efficacy of cranberry products in UTI prevention, and other natural therapeutics reported for UTI.

Evaluation of Anti-Diabetic Potential of Corn Silk in High-Fat Diet/ Streptozotocin-Induced Type 2 Diabetes Mice Model

BACKGROUND

Corn silk is the elongated stigma of the female flower of Zea mays and traditionally used to treat diabetes mellitus (DM).

OBJECTIVE

To investigate the beneficial effects of corn silk extract (CSE) on HFD/STZ-induced diabetic C56BL/6J mice.

METHODS

Establishment of a T2DM model through feeding HFD combined with STZ. T2DM was randomly divided into 5 groups: diabetic control mice treated with vehicle (model group, n=10), metformin- treated group (metformin: 150 mg/kg.d, n=10), three CS-treated groups (CS: 300, 600 and 1200 mg/kg.d, n=10). After four weeks of CS treatment, the body weight, FBG, IR, TC, TG, LDL-C, MDA and SOD levels of mice were measured. In addition, the liver tissue was histomorphologically analyzed by HE stain followed a light microscopy observation.

RESULTS

4-week CSE treatment significantly reduced FBG and enhanced the glucose tolerance; improved IR indicated by decreased HOMA-IR and elevated ISI; alleviated hyperlipidemia indicated by decreased TC, TG, LDL-C, and increased HDL-C; reduced oxidative stress by decreased MDA and elevated SOD activity; decreased hepatic lipid accumulation and prevented liver tissue morphological change in T2DM. In addition, CSE treatments effectively prevent the weight gain loss of diabetic mice.

CONCLUSION

These results confirmed the traditionally claimed benefits of corn silk on DM, which suggested that the corn silk possessed the anti-diabetic potential and could be further developed as a cheap and plant-derived agent for the treatment of type 2 diabetes mellitus.

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.

Studies on the binding characteristics of three polysaccharides with different molecular weight and flavonoids from corn silk (Maydis stigma)

Polysaccharides and flavonoids co-existed in corn silk (Maydis stigma) could interact inevitably during processing and digestion. In this study, the binding interaction between three polysaccharides with different molecular weight and flavonoids from corn silk was characterized using molecular dynamic and thermodynamic simulation. And the corn silk polysaccharides-flavonoids complex (CSP - CSF complex) was characterized using fourier transform infrared (FT-IR) spectra, circular dichroism (CD), scanning electron microscope (SEM) and differential scanning calorimetry (DSC). The three polysaccharides from corn silk showed the molecular weight distributions of 43.3 kDa, 61.3 kDa and 106.6 kDa, respectively, and they had the same monosaccharide types with different ratios. The adsorption of flavonoids to polysaccharides might be mostly driven by van der Waals forces and hydrogen bonding, and it could be described through various isothermal models and thermodynamic equations such as Langmuir, Freundlich equations and Clausius-Clapeyron equation. This type of interactions could improve the biological activities of polysaccharides such as α-amylase and α-glucosidase inhibition.

ent-Kaurane Diterpenoids with Neuroprotective Properties from Corn Silk ( Zea mays)

Thirteen new ent-kaurane diterpenoids, stigmaydenes A-M (1-13), together with two known compounds (14, 15), were isolated from the crude extract of corn silk ( Zea mays). The structures of the compounds were confirmed by comprehensive spectroscopic analyses. The absolute configuration of compound 1 was defined by single-crystal X-ray diffraction. The absolute configurations of the compounds were also confirmed by comparison of experimental and calculated specific rotations. The compounds were evaluated for their neuroprotective effects against H₂O₂-induced SH-SY5Y cell injury, and compound 8 was active at 100 μM, as determined by flow cytometry (annexin V-FITC/PI staining) and Hoechst 33258 staining. The results suggested that compound 8 could protect neuronal cells from H₂O₂-induced injury by inhibiting apoptosis in SH-SY5Y cells.

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.

Anti-inflammatory effect of volatile oil from Schizonepeta tenuifolia on carrageenin-induced pleurisy in rats and its application to study of appropriate harvesting time coupled with multi-attribute comprehensive index method

ETHNOPHARMACOLOGICAL RELEVANCE

Schizonepeta tenuifolia Briq. (ST) herbs have been used as a Traditional Chinese Medicine (TCM) for treating colds for thousands of years. The volatile oil is considered as the main material basis responsible for the efficacy of ST and has attracted lots of attention on its anti-inflammatory effect recently.

AIM OF STUDY

This paper investigated the anti-inflammatory effects of the distilled volatile oils from Schizonepeta tenuifolia (STVO) that were collected at different harvesting times on carrageenin-induced pleurisy in rats. Based on the anti-inflammatory effects, instead of contents of marker components, we aim to evaluate the quality and determine the appropriate harvesting time of ST.

MATERIALS AND METHODS

There were eleven groups with eight male rats in each randomly. They were model group, control group, positive group (dexamethasone) and eight groups treated with eight STVOs at different harvesting times. All treatments were performed by gavage and administered once a day on four consecutive days. One hour after the last treatments, except the rats in control group, those in other groups were treated with carrageenin to induce the pleurisy. Four hours later, all the rats were sacrificed and their pleurisy exudates and lung tissues were collected for further analysis. To evaluate the comprehensive anti-inflammatory effect of the eight STVOs, multi-attribute comprehensive index method (MACIM) was used to obtain the integration of various effects.

RESULTS

All the eight STVOs could decrease the seven indicators relating to pleurisy, which were exudate volume, leukocytes, protein level, myeloperoxidase (MPO), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α) and interleukine-1β (IL-1β). Majority of these decreases were significant (P<0.01, P<0.05). As far as each indicator was concerned, each STVO showed different effect from others. With MACIM, it was found that STVO in Group 6 was the most effective one with the highest V_s and appropriate harvesting time of ST was in late September.

CONCLUSIONS

The study may provide scientific basis to further understanding of the mechanism of STVO in anti-inflammatory effect of carrageenin-induced pleurisy. Meanwhile, this study also provides a new access to determining the appropriate harvesting time of TCM and even evaluating the quality of TCM.

Toxicological evaluation of the flavonoid-rich extract from Maydis stigma: Subchronic toxicity and genotoxicity studies in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Maydis stigma (corn silk) has a long history of use as a traditional herbal medicine or functional food in China and many other countries and has been listed in the Chinese Pharmacopea. However, little data about its potential toxicity is available.

AIM OF THE STUDY

In this study, we evaluated the subchronic toxicity and genotoxicity of the flavonoid-rich extract from Maydis stigma (FMS) in mice.

MATERIALS AND METHODS

In the subchronic toxicity study, the FMS was administered orally to mice at doses of 2.50, 5.00 and 10.00g/kg/day for 28 consecutive days. At the end of experiment, general clinical signs, mortality, haematological, biochemical and histopathological parameters were examined. The genotoxicity of FMS was also evaluated by the micronucleus assay and the sperm malformation assay.

RESULTS

All animals survived until the scheduled necropsy, and no statistically significant or toxicologically relevant differences were observed in any of the FMS-treatment groups, compared with the control group. The no-observed-adverse-effect level (NOAEL) was determined as 10.00g/kg/day. Based on the results of the micronucleus assay and the sperm malformation assay, no evidence of genotoxicity was found either in somatic cells or germ cells even at an experimental upper limit dose (10.00g/kg/day).

CONCLUSIONS

The results of the present studies might support the safe use of FMS as a functional food, food additive and natural remedy.

Zea mays, Stigma maydis prevents and extenuates acetaminophen-perturbed oxidative onslaughts in rat hepatocytes

CONTEXT

Zea mays L. (Poaceae) Stigma maydis is an underutilized product of corn cultivation finding therapeutic applications in oxidative stress-related disorders.

OBJECTIVES

This study investigated its aqueous extract against acetaminophen (APAP)-perturbed oxidative insults in rat hepatocytes.

MATERIALS AND METHODS

Hepatotoxic rats were orally pre- and post-treated with the extract (at 200 and 400 mg/kg body weight) and vitamin C (200 mg/kg body weight), respectively, for 14 days. Liver function, antioxidative and histological analyses were thereafter evaluated.

RESULTS

The APAP-induced marked (p < 0.05) increases in the activities of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, gamma glutamyl transferase and the concentrations of bilirubin, oxidized glutathione, protein carbonyls, malondialdehyde, conjugated dienes, lipid hydroperoxides and fragmented DNA were dose-dependently extenuated in the extract-treated animals. The extract also significantly (p < 0.05) improved the reduced activities of superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase as well as total protein, albumin and glutathione concentrations in the hepatotoxic rats. These improvements may be attributed to the bioactive constituents as revealed by the gas chromatography-mass spectrometric chromatogram of the extract. The observed effects compared favourably with vitamin C and are informative of hepatoprotective and antioxidative attributes of the extract and were further supported by the histological analysis.

CONCLUSION

The data from the present findings suggest that Stigma maydis aqueous extract is capable of preventing and ameliorating APAP-mediated oxidative hepatic damage via enhancement of antioxidant defence systems.

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

BACKGROUNG/OBJECTIVES

The study was performed to investigate the effects and mechanisms of action of high maysin corn silk extract on body weight and fat deposition in experimental animals.

MATERIALS/METHODS

A total of 30 male C57BL/6J mice, 4-weeks-old, were purchased and divided into three groups by weight using a randomized block design. The normal-fat (NF) group received 7% fat (diet weight basis), the high-fat (HF) group received 25% fat and 0.5% cholesterol, and the high-fat corn silk (HFCS) group received high-fat diet and high maysin corn silk extract at 100 mg/kg body weight through daily oral administration. Body weight and body fat were measured, and mRNA expression levels of proteins involved in adipocyte differentiation, fat accumulation, fat synthesis, lipolysis, and fat oxidation in adipose tissue and the liver were measured.

RESULTS

After experimental diet intake for 8 weeks, body weight was significantly lower in the HFCS group compared to the HF group (P < 0.05), and kidney fat and epididymal fat pad weights were significantly lower in the HFCS group compared to the HF group (P < 0.05). In the HFCS group, CCAAT/enhancer binding protein-β, peroxisome proliferator-activated receptor-γ1 (PPAR-γ1), and PPAR-γ2 mRNA expression levels were significantly reduced (P < 0.05) in the epididymal fat pad, whereas cluster of differentiation 36, lipoprotein lipase, acetyl-CoA carboxylase-1, sterol regulatory element binding protein-1c, pyruvate dehydrogenase kinase, isozyme-4, glucose-6-phosphate dehydrogenase, and stearoyl-CoA desaturase-1 mRNA expression levels were significantly decreased in liver and adipose tissues (P < 0.05). In the HFCS group, mRNA expression levels of AMP-activated protein kinase, hormone-sensitive lipase, and carnitine palmitoyltransferase-1 were elevated (P < 0.05).

CONCLUSIONS

It can be concluded that high maysin corn silk extract inhibits expression of genes involved in adipocyte differentiation, fat accumulation, and fat synthesis as well as promotes expression of genes involved in lipolysis and fat oxidation, further inhibiting body fat accumulation and body weight elevation in experimental animals.

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.

C-Glycosylflavones Alleviate Tau Phosphorylation and Amyloid Neurotoxicity through GSK3β Inhibition

Alzheimer's disease (AD) is the most common brain disorder worldwide. Aberrant tau hyperphosphorylation and accumulation play critical roles in the formation of neurofibrillary tangles highly associated with neuronal dysfunction and cognitive impairment in AD pathogenesis. Glycogen synthase kinase-3β (GSK3β) is a key kinase responsible for tau hyperphosphorylation. Selective inhibition of GSK3β is a promising strategy in AD therapy. Corn silks (CS, Zea mays L.) have been traditionally used as a medicinal herb and recently noted for their potentially cognitive benefits. However, the neuroprotective components of CS and their molecular mechanism have received little attention to date. As part of our effort screening phytochemicals against a broad panel of kinases targeting AD tauopathy, we found inhibition of GSK3β by CS extracts. Subsequent bioassay-guided fractionation led to the isolation and identification of two 6-C-glycosylflavones, isoorientin (1) and 3'-methoxymaysin (2), with selective inhibition against GSK3β in vitro. Enzyme kinetics and molecular docking studies demonstrated that 1 specifically inhibited GSK3β via an ATP noncompetitive mechanism, acting as a substrate competitive inhibitor of GSK3β. Further in vitro cellular studies demonstrated that 1 effectively attenuated tau phosphorylation mediated by GSK3β and was neuroprotective against β-amyloid-induced tau hyperphosphorylation and neurotoxicity in SH-SY5Y cells. The C-glycosylflavones represent new lead candidates with a novel mechanism of action for the development of AD phytopharmaceuticals.

Safety Evaluation, in Vitro and in Vivo Antioxidant Activity of the Flavonoid-Rich Extract from Maydis stigma

This study aimed to assess the acute toxicity and safety of flavonoid-rich extract from Maydis stigma (FMS) in mice. The in vitro antioxidant activity of FMS was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethyl-benzthiazoline-6-sulphonate) (ABTS) scavenging assays. Furthermore, the in vivo antioxidant of FMS against ethanol-induced oxidative damage in mice was determined by analysis of the serum total superoxide dismutase (T-SOD) activity, malondialdehyde (MDA) content, liver tissue glutathione (GSH) content, and protein carbonyl (PC) content in liver tissue. The oral administration of FMS at doses of 30 g/kg did not cause death in mice, and there were no significant biologically adverse effects in mice. These results indicated that the median lethal dose (LD₅₀) is higher than this dose. The IC₅₀ values of FMS for the DPPH and ABTS scavenging activity were 50.73 and 0.23 mg/mL, respectively. Meanwhile, FMS could significantly enhance T-SOD activity, reduce MDA content in the serum, increase GSH content, and decrease PC content in the liver tissue at the tested doses (25, 50, 100, 200 mg/kg·day). These results indicate that FMS can be generally regarded as safe and used potentially as a bioactive source of natural antioxidants.

Toxicological evaluations of Stigma maydis (corn silk) aqueous extract on hematological and lipid parameters in Wistar rats

Despite the acclaimed phytotherapeutic attributes of Stigma maydis in folkloric medicine, there is paucity of information on its toxicity profile on hematological and lipid parameters. The toxicological effect of aqueous extract of corn silk at 100, 200 and 400 mg/kg body weight on hematological indices in Wistar rats were evaluated progressively at 24 h after 1, 7, 14, 21 and 28 days. Lipid parameters were also analyzed at the end of the experimental period. We observed that the extract did not exhibit any significant (p > 0.05) effect on red blood cells, hematocrit, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and mean platelet volume at all the tested doses. The study however showed a significant increase in the serum levels of white blood cell, platelet, lymphocytes, high-density lipoprotein cholesterol; as well as feeding pattern in the animals, while the concentrations of total cholesterol, low-density lipoprotein cholesterol, and artherogenic index value were significantly lowered. These findings are suggestive of non-hematotoxic potential of the extract. Overall, the effect exhibited by corn silk extract in this study proved that, it is unlikely to be hematotoxic and could be a good candidature in the management of coronary heart diseases if consumed at the doses investigated.

Characterizing the human equivalent dose of herbal medicines in animal toxicity studies

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicines have been generally believed to be safe. With the increasing use of herbal medicine worldwide, however, the safety of traditional herbal drugs frequently becomes a medical issue.

AIM OF THE STUDY

This study was aimed to characterize the safe dose of herbal medicines through the systematic review for "human equivalent dose (HED)" from animal-based toxicity studies.

METHODS AND MATERIALS

A literature search for animal-based toxicity studies of herbal medicines in eight databases, including PubMed and Embase, was performed without language restriction. From the "no observed adverse effect level (NOAEL)" of each animal study, HED values were then calculated according to the composition (single or multiple herbs) and indication of the medicines.

RESULTS

Among 729 relevant articles identified in the initial screening, 112 (233 studies comprising 105 single-herb and 128 multiple-herb studies) that met our inclusion criteria were finally reviewed. The total average HED value (from mouse, rat, rabbit and dog) was 278.1±358.0 mg/kg, and the values for single- and multiple-herb studies were 322.7±488.4 mg/kg and 241.5±189.2 mg/kg, respectively. When the studies were analyzed according to herbal drug indication, drugs used for revitalization had the highest HED value (433.0±265.2 mg/kg), while those for infectious diseases had the lowest (110.6±118.6 mg/kg).

CONCLUSIONS

Our results provide important information regarding the safe dose of herbal medicines; thus, these data offer researchers and practitioners information critical for drug development or clinical application.

Evaluation of anti-inflammatory and mechanism of action of extract of Macrosiphonia longiflora (Desf.) Müll. Arg

ETHNOPHARMACOLOGICAL RELEVANCE

Macrosiphonia longiflora (Desf.) Müll. Arg (Apocynaceae), popularly known as 'velame' and 'velame branco', is a native subshrub that grows in the Brazilian Cerrado. This plant is widely used in traditional medicine in the form of decoction and infusion, particularly as anti-inflammatory, depurative, anti-rheumatic, antisyphilitic and antiulcer remedy. There is no available information in the literature that has addressed its pharmacological activity and phytochemical analysis.

AIM OF THE STUDY

This study aimed to evaluate the anti-inflammatory pharmacological profile of the hydroethanolic extract of Macrosiphonia longiflora, using in vivo and in vitro acute inflammation experimental models, as well as investigate the roles of cytokines and nitric oxide in its mechanism of action, and including phytochemical analysis constitution of its hydroethanolic extract.

MATERIALS AND METHODS

Hydroethanolic (70%) extract of Macrosiphonia longiflora (HEMl) was prepared by maceration. The preliminary phytochemical analysis was performed according to procedures described in the literature. Selected secondary metabolites detected were quantified by spectrophotometry and high performance liquid chromatography (HPLC). Its cytotoxic potential in Chinese hamster ovary (CHO-k1) epithelial cell lines was evaluated using Alamar Blue. in vivo anti-inflammatory activity was evaluated with carrageenan- and dextran-induced paw edemas, carrageenan-induced pleurisy in rats and lipopolysaccharide (LPS)-induced peritonitis in mice. The in vitro anti-inflammatory activity was evaluated using RAW 264.7 cells stimulated with LPS and interferon (INF)-γ. Effects of HEMl on the inflammatory cytokines (IL-1β, IL-10, IL-17, INF-γ and TNF-α) concentrations in the peritoneal lavage were evaluated using commercial ELISA kits, while the Griess method was employed to determine nitric oxide (NO) concentrations in the peritoneal lavage, as well as in the supernatants of RAW 264.7 cells.

RESULTS

Preliminary phytochemical analysis, revealed the presence of phenolics compounds, terpenoids, alkaloids and flavonoids. Spectrophotometric analysis revealed the presence of relatively high content of phenolics and flavonoids in HEMl. HPLC analysis confirmed the presence of the quantified compounds and demonstrated the presence of ellagic acid in the detected matrix of compounds. HEMl appeared to be non-cytotoxic. It effectively inhibited (p<0.05) paw edema induced by carrageenan and dextran. Furthermore, HEMl also significantly reduced exudates volume and leukocyte migration in the carrageenan-induced pleurisy and LPS-induced peritonitis, neutrophils counts in LPS-induced peritonitis. HEMl also acts by effectively inhibiting the following inflammatory cytokines: IL-1β and IL-10 levels in the peritoneal lavage, but had no effect on IL-17 level in the peritonitis model. In addition, HEMl had no effect on the levels of tumor necrosis factor alpha (TNF-α) present in the peritoneal lavage and cells supernatants. The concentration of NO, as assessed by measurement of nitrite (NO2(-)), showed that pretreatment with HEMl reduced NO significantly in the peritoneal lavage and in RAW 264.7 cells co-stimulated with LPS and INF-γ.

CONCLUSION

The results obtained in this study indicate that HEMl possesses very low cytotoxic potential. In addition, it demonstrated a potent anti-inflammatory activity in both the in vivo and in vitro models of acute inflammation. The anti-inflammatory effect is partly related to the inhibition of IL-1β, IL-10, and nitric oxide releases, but independent of TNF-α and IL-17 modulation. Phytochemical analysis revealed the predominant presence of the flavonoids (naringin, rutin, myricetin, morin, quercetin, (±)-naringenin, and luteolin) and phenols (ellagic acid), which are possibly involved in the anti-inflammatory effect of HEMl. The current study provided supportive evidence for the popular use of HEMl in the treatment of inflammatory conditions, and shed more light on the possible roles of the inflammatory cytokines in its mechanisms of action as anti-inflammatory agent.

Inhibitory effect of corn silk on skin pigmentation

In this study, the inhibitory effect of corn silk on melanin production was evaluated. This study was performed to investigate the inhibitory effect of corn silk on melanin production in Melan-A cells by measuring melanin production and protein expression. The corn silk extract applied on Melan-A cells at a concentration of 100 ppm decreased melanin production by 37.2% without cytotoxicity. This was a better result than arbutin, a positive whitening agent, which exhibited a 26.8% melanin production inhibitory effect at the same concentration. The corn silk extract did not suppress tyrosinase activity but greatly reduced the expression of tyrosinase in Melan-A cells. In addition, corn silk extract was applied to the human face with hyperpigmentation, and skin color was measured to examine the degree of skin pigment reduction. The application of corn silk extract on faces with hyperpigmentation significantly reduced skin pigmentation without abnormal reactions. Based on the results above, corn silk has good prospects for use as a material for suppressing skin pigmentation.

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.