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This study presents the determination of the total antioxidant capacity (TAC) in twenty edible plants traditionally considered as having pro-health properties and commonly found in East Asia and the Middle East. The aim of the study was to apply a flow-injection amperometric detector (Blizar antioxidant analyzer) for rapid measurement of TAC. Three extraction solvents were used (water, 40% ethanol and 96% ethanol). On average, the edible plants that presented the highest TAC [expressed as gallic acid equivalents (GAE)] for the three extraction solvents were Rosa rugosa (34 mg/g GAE), Scutellaria baicalensis (22.9 mg/g GAE), Forsythia suspensa (11.7 mg/g GAE), Carthamus tinctorius (11.5 mg/g GAE), Smilacis glabrae rhizoma (10.8 mg/g GAE), Citri reticulatae pericarpium (8.8 mg/g GAE), Apocynum venetum (7.6 mg/g GAE) and Glycyrrhiza uralensis (7.5 mg/g GAE). This investigation contributes to the current knowledge on the overall antioxidant activity of edible plants traditionally consumed for expected pro-health properties, identifying specimens exhibiting high TAC determined by a rapid and low cost amperometric method.

Purpose The purpose of this paper is to determine the antioxidant activity of natural polyphenols from larch wood by the amperometric method. Design/methodology/approach Direct measurements of antioxidant activity were carried out by the amperometric method in an oxidizing mode with glassy carbon as a working electrode, set potential +1.3V and using a flow-injection system with 2.2 mM phosphoric acid as the mobile phase with a flow rate of 1.2 ml/min. Findings The reported results show the following values of antioxidant activity for the tested compounds: (−)-secoisolariciresinol – 0.199 ± 0.002 mg/L (p < 0.05); isolariciresinol – 0.196 ± 0.002 mg/L (p < 0.05); lariciresinol - 0.222 ± 0.001 mg/L (p < 0.05); O-isopropylidene derivative of (−)-secoisolariciresinol - 0.143 ± 0.002 mg/L (p < 0.05); (+)-dihydroquercetin – 0.153 ± 0.002 mg/L (p < 0.05); and quercetin – 0.521 ± 0.001 mg/L (p < 0.05). The last product was tested as the reference of a widely used current antioxidant. General tendencies of determined values of antioxidant activity for studied compounds are in good correlation with published data as determined by the t-BuOOH-initiated lipid peroxidation method. Practical implications Described results show practical applicability of the amperometric method as being faster and cheaper in comparison to other methods, including oxygen radical absorbance capacity (ORAC) assay or 2,2′diphenyl-1-picrylhydrazyl (DPPH) reagent based assay. Originality/value The described results show the first-time application of the amperometric method for the evaluation of the antioxidant activity of phenolic compounds from larch wood.

Epidemiological studies have provided the evidence that regular consumption of fruits and vegetables reduce the risk of pathological condition such as cardiovascular disease, cancer, inflammation, and aging. Among fruits, berries are considered as superfruits due to their highly packed phytochemicals comprising phenolic acids, flavonoids viz. flavonols, flavanols, and anthocyanins. These bioactive compounds are associated with significant antioxidant, antidiabetic, antiinflammation, and anticancer properties. This review highlights the basic information and interesting findings of some selected commercial berries with their phytochemical composition, antioxidant properties, and potential health benefits to human.

Antioxidants are substances that prevent oxidation of other compounds or neutralize free radicals. Spices and herbs are rich sources of antioxidants. They have been used in food and beverages to enhance flavor, aroma and color. Due to their excellent antioxidant activity, spices and herbs have also been used to treat some diseases. In this review article, the chemical composition and antioxidant activity of spices and culinary herbs are presented. The content of flavonoids and total polyphenols in different spices and herbs are summarized. The applications of spices and their impacts on human health are briefly described. The extraction and analytical methods for determination of antioxidant capacity are concisely reviewed.

Polysaccharides are naturally occurring biomacromolecules composed of carbohydrate molecules linked by glycosidic bonds. A number of polysaccharides are known to possess beneficial therapeutic effects against inflammation, diabetes, cardiovascular diseases, and cancers. Indeed, polysaccharides are reportedly effective free radical scavengers and antioxidants, thereby playing a critical role in the prevention of damage to living organisms under oxidative stress. In this review we provide an overview of the sources, extraction, and antioxidant activities of some natural polysaccharides.

Numerous epidemiological studies indicate that consumption of antioxidant-rich foods is beneficial to human health and reduces the risks of dangerous diseases and premature aging. Among natural antioxidants some stand out for their powerful activity and health benefits and they are epigallocatechin gallate, quercetin, curcumin, resveratrol, hydroxytyrosol, astaxanthin, lycopene, dihydroquercetin, and lignans. Preclinical, clinical, and therapeutic studies of these antioxidants in their pure form or in their combination have shown positive health benefits. This review highlights basic information and interesting findings with their source, structure, antioxidant properties, and potential health benefits to human.

This review summarizes published information concerning the determination of antioxidant activity (AA) in coffee samples by various methods (ORAC, FRAP, TRAP, TEAC, etc.) in vitro and limited data of antiradical activity of coffee products in vitro and in vivo. Comparison is carried out of the AA of coffee Arabica and coffee Robusta roasted at different temperatures as well as by different roasting methods (microwave, convection, etc.). Data on the antiradical activity of coffee is provided. The antioxidant activity of coffee, tea, cocoa, and red wine is compared. At the end of this review, the total antioxidant content (TAC) of coffee samples from 21 coffee-producing countries as measured by an amperometric method is provided. The TAC of green and roasted coffee beans is also compared.

Interest in antioxidants and antioxidant therapy has been growing during the last decade. Antioxidants are generally considered to have the capability to protect people from harmful effects of reactive oxygen and nitrogen species (RONSs), including free radicals (FR), when these are present in excessive amounts. RONS and free radicals perform a variety of useful biological functions in the body. Their excess is controlled by a natural antioxidant protection system in humans. This protection is provided at three levels: by simple molecules (such as cysteine, glutathione (GSH), uric acid, ubiquinol, etc.), medium-molecular weight, and high molecular weight compounds (enzymes, etc.). Under certain adverse conditions, this system does not manage to provide adequate protection and the RONSs and free radicals begin to damage vital DNA, proteins, and lipids. In such a case, antioxidant therapy, which includes antioxidant supplements and foods containing natural antioxidants, has been suggested to be of possible benefit. However, there are many unresolved issues related to the effective use of an antioxidant therapy: 1. A person should know the content of antioxidants in everyday food products and its relation to the storage time and processing methods used. 2. How many antioxidants should a person consume? It is known that at high concentrations some antioxidants become pro-oxidants. 3. Are the antioxidants consumed by a person bioavailable and, if so, to what extent; for some food products, bioavailability has already been determined but most foods have not been examined. 4. Many antioxidants are digested by intestinal microflora before they reach the systemic blood circulation. 5. Even those antioxidants that do reach the blood are often rapidly metabolized; the role of their metabolites is unclear; there is some evidence that certain metabolites are also antioxidants. 6. How long do antioxidants and their metabolites stay in the body; how are they distributed in different organs; and when are they excreted? In order to answer these questions, the pharmacokinetics of antioxidants should be studied. 7. The presence of oxidative stress, i.e., excess amounts of RONSs and free radicals, can be detected by various oxidative stress markers but, in order to see the whole picture, the actual concentrations of RONSs

Antioxidant activity of different types of tea (green, oolong, black, pu-erh ) were measured using different modern methods. Several types of commercially available teas, from various manufacturers were tested for antioxidant content using the amperometric method, the data is displayed here. Data gathered about antioxidant content of these different tea samples can be used to estimate quality and type of tea. The data collected using this method is also important when trying to account for the normal daily consumable antioxidant of healthy people and also patients using clinical antioxidant therapy.

This review discusses the bioavailability of active components of green and black teas--in hot brewed tea, cold tea, and dietary supplements containing tea extracts, based on literature published in 1995-2011. Many publications demonstrate that consumption of tea increases the antioxidant status of a person (between 3.5-76%) and reduces the concentration of oxidative stress biomarkers in biological fluids. In 1-2 hours after tea intake, epigallocatechin gallate (EGCG), epicatechin (EC), and epicatechin gallate (ECG) at a level of 5-150 ng/ml were detected in plasma by HPLC. The results of pharmacokinetics and metabolism of biologically active tea components analyzed within 24 hours in plasma, urine, and feces by HPLC-MS and GC-MS are presented. Dozens of metabolites were identified in urine and plasma—these are methylated, sulfated, and glucuronide conjugates of catechins. Some metabolites were shown to have high antioxidant activity. The role of the small intestine and colon in absorption of catechins was also identified.