Phytochemical content and antioxidant activities of Rhubarb (Rheum emodi)

Medicinal plants have varying natural products and several antioxidants. Antioxidants play a principal function to protect against destruction caused by oxidative stress (OS), <i>Rheum emodi</i> is not an exception, in which it is reported to have compounds that possess antioxidant activity, like polyphenolic compounds. In addition to that, other compounds have proven to have antidiabetic, antimicrobial, antifungal, cytotoxic, hepatoprotective, and nephroprotective activities. This study aimed to quantify the water extract of a powdered plant of <i>R. emodi</i> to evaluate its ability to scavage free radicals. Total phenolic, total flavonoid contents, and reducing ability were measured to consider possible sources of future novel antioxidants in plants. The TPC, TFC, and reducing power assay increased with increasing concentrations of <i>R. emodi</i>. At 1000 µg/ml, the absorbance ranged from 1.437 for TPC, 1.602 for TFC, and 1.638 for reducing power assay, which is more than the absorbance of the standards at the same concentration. The extracted content of reducing power, phenolic, and flavonoid compounds were higher than the standard pyrogallol, quercetin, and ascorbic acid.

The Involvement of Glucose in Hydrogen Gas-Medicated Adventitious Rooting in Cucumber

Hydrogen gas (H2) and glucose (Glc) have been reported as novel antioxidants and signal molecules involved in multiple biological processes in plants. However, the physiological roles and relationships of H2 and Glc in adventitious rooting are less clear. Here, we showed that the effects of different concentrations Glc (0, 0.01, 0.05, 0.10, 0.50 and 1.00 mM) on adventitious rooting in cucumber were dose-dependent, with a maximal biological response at 0.10 mM. While, the positive roles of hydrogen rich water (HRW, a H2 donor)-regulated adventitious rooting were blocked by a specific Glc inhibitor glucosamine (GlcN), suggesting that Glc might be responsible for H2-regulated adventitious root development. HRW increased glucose, sucrose, starch and total sugar contents. Glucose-6-phosphate (G6P), fructose-6-phosphate (F6P) and glucose-1-phosphate (G1P) contents were also increased by HRW. Meanwhile, the activities of sucrose-related enzymes incorporating sucrose synthase (SS) and sucrose phosphate synthase (SPS) and glucose-related enzymes including hexokinase (HK), pyruvate kinase (PK) and adenosine 5′-diphosphate pyrophosphorylase (AGPase) were increased by HRW. Moreover, HRW upregulated the expression levels of sucrose or glucose metabolism-related genes including CsSuSy1, CsSuSy6, CsHK1, CsHK3, CsUDP1, CsUDP1-like, CsG6P1 and CsG6P1-like. However, these positive roles were all inhibited by GlcN. Together, H2 might regulate adventitious rooting by promoting glucose metabolism.

Antioxidant Profiling of Ginger via Reaction Flow Chromatography

Reaction flow (RF) chromatography is a powerful and efficient approach that utilizes conventional high-performance liquid chromatography (HPLC)–ultraviolet (UV)–visible detection. This technique exploits a novel column end-fitting and an extra HPLC pump that delivers a reagent specific for selective detection, in particular the antioxidant profiling of natural products. This study employed RF for the first time to identify antioxidants in a commercial ginger sample. This demonstrated the previously validated assay's ease and power to extract information about the natural product's antioxidant properties. Due to the simplicity involved with data analysis and peak matching process, the following information was revealed between the chemical and antioxidant profiles: three of the strongest antioxidant activity peaks in the ginger sample (593 nm) did not correlate with the three most abundant chemical profile peaks (UV absorbance at 254 and 280 nm); the ratio of seven antioxidant peaks may be potentially used for food authenticity purposes, and future research should target these peaks for the early discovery of novel antioxidants sourced in ginger. Utilization of this previously validated assay provided the resolution of numerous peaks in the ginger extract and information associated with their antioxidant attributes and chemical abundance. This approach is more informative than total antioxidant assays that lack compound specificity information. Furthermore, it is superior to mass spectrometric (MS) assays that cannot evaluate each compound's antioxidant strength, and does not involve the expense involved in the acquisition and maintenance of the MS detection hardware, and does not require the high level of expertise needed to conduct the MS data analysis.

Antioxidants in Fish Sperm and the Potential Role of Melatonin

In recent years, the effects of novel antioxidants have played an important role in the research focusing on fish cell protection. As food demand grows, aquaculture production becomes more intensive, and fish are more exposed to oxidative stress conditions, like high densities, temperature shifting, frequent fish handling and samplings, and prophylactic or disease treatments, which expose fish to a different environment. Particularly in reproduction, germ cells lose antioxidant capacity with spermatogenesis, as spermatozoa are more prone to oxidative stress. Antioxidants have been used in a variety of fish physiological problems including in reproduction and in the establishment of cryopreservation protocols. From the most used antioxidants to natural plant food and herbs, and endogenously produced antioxidants, like melatonin, a review of the literature available in terms of their effects on the protection of fish spermatozoa is presented here in a classified structure. Several direct and indirect approaches to improve gamete quality using antioxidants administration are mentioned (through feed supplementation or by adding in cryopreservation media), as well as factors affecting the efficiency of these molecules and their mechanisms of action. Special attention is given to the unclear melatonin pathway and its potential scavenger activity to prevent and counteract oxidative stress damage on fish spermatozoa.

Oxidative Stress and Antioxidant Treatments in Cardiovascular Diseases

Oxidative stress plays a key role in many physiological and pathological conditions. The intracellular oxidative homeostasis is tightly regulated by the reactive oxygen species production and the intracellular defense mechanisms. Increased oxidative stress could alter lipid, DNA, and protein, resulting in cellular inflammation and programmed cell death. Evidences show that oxidative stress plays an important role in the progression of various cardiovascular diseases, such as atherosclerosis, heart failure, cardiac arrhythmia, and ischemia-reperfusion injury. There are a number of therapeutic options to treat oxidative stress-associated cardiovascular diseases. Well known antioxidants, such as nutritional supplements, as well as more novel antioxidants have been studied. In addition, novel therapeutic strategies using miRNA and nanomedicine are also being developed to treat various cardiovascular diseases. In this article, we provide a detailed description of oxidative stress. Then, we will introduce the relationship between oxidative stress and several cardiovascular diseases. Finally, we will focus on the clinical implications of oxidative stress in cardiovascular diseases.

Anthocyanins from Purple Tomatoes as Novel Antioxidants to Promote Human Health

Anthocyanins are plant secondary metabolites belonging to the class of polyphenols, whose beneficial roles in the prevention and treatment of several important human diseases have been demonstrated in many epidemiological studies. Their intake through diet strictly depends on the eating habits, as anthocyanins are contained in red and purple fruit and vegetables as well as in some processed foods and beverages, such as red wine. Genetic engineering and breeding programs have been recently carried out to increase the content of anthocyanins in candidate plant species which cannot offer satisfactory levels of these precious compounds. Tomato (Solanum lycopersicum) is a vegetable commodity where these strategies have resulted in success, leading to the production of new anthocyanin-rich fruit varieties, some of which are already marketed. These varieties produce purple fruits with a high nutraceutical value, combining the health benefits of the anthocyanins to the other classical tomato phytochemicals, particularly carotenoids. The antioxidant capacity in tomato purple fruits is higher than in non-anthocyanin tomatoes and their healthy role has already been demonstrated in both in vitro and in vivo studies. Recent evidence has indicated a particular capacity of tomato fruit anthocyanins to act as scavengers of harmful reactive chemical species and inhibitors of proliferating cancer cells, as well as anti-inflammatory molecules.

Macrocycles and Supramolecules as Antioxidants: Excellent Scaffolds for Development of Potential Therapeutic Agents

Oxidative stress due to the high levels of reactive oxygen species (ROS) that damage biomolecules (lipids, proteins, DNA) results in acute inflammation. However, without proper intervention, acute inflammation progresses to chronic inflammation and then to several chronic diseases, including cancer, myocardial infarction, cardiovascular diseases, chronic inflammation, atherosclerosis, and more. There has been extensive research on the antioxidants of natural origin. However, there are myriad possibilities for the development of synthetic antioxidants for pharmacological applications. There is an increasing interest in the identification of novel synthetic antioxidants for the modulation of biochemical processes related to ROS. In this regard, derivatives of supramolecules, such as calix[n]arene, resorcinarene, calixtyrosol, calixpyrrole, cucurbit[n]uril, porphyrin etc. are gaining attention for their abilities to scavenge the free radicals. Supramolecular chemistry offers excellent scaffolds for the development of novel antioxidants that can be used to modulate free radical reactions and to improve the disorders related to oxidative stress. This review focuses on the interdisciplinary approach for the design and development of novel synthetic antioxidants based on supramolecular scaffolds, with potentially protective effects against oxidative stress.