Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

Phenolic compounds as well as flavonoids are well-known as antioxidant and many other important bioactive agents that have long been interested due to their benefits for human health, curing and preventing many diseases. This review attempts to demonstrate an overview of flavonoids and other phenolic compounds as the interesting alternative sources for pharmaceutical and medicinal applications. The examples of these phytochemicals from several medicinal plants are also illustrated, and their potential applications in pharmaceutical and medical aspects, especially for health promoting e.g., antioxidant effects, antibacterial effect, anti-cancer effect, cardioprotective effects, immune system promoting and anti-inflammatory effects, skin protective effect from UV radiation and so forth are highlighted.

https://www.mdpi.com/2305-6320/5/3/93/pdf

Flavonoids and Other Phenolic Compounds from Medicinal Plants for Pharmaceutical and Medical Aspects: An Overview.

The objective of this study was to investigate how 6 commonly used solvent systems affected the yields of phenolic substances and the antioxidant capacity of extracts from 8 major classes of food legumes. Several antioxidant-related phytochemical compositions, namely, total phenolic content (TPC), total flavonoids content (TFC), and condensed tannins content (CTC), were investigated. In addition, antioxidant activities were tested using 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging, ferric-reducing antioxidant power (FRAP), and the oxygen radical absorbance capacity (ORAC). The results showed that the 50% acetone extracts exhibited the highest TPC for yellow pea, green pea, chickpea, and yellow soybean. Acidic 70% acetone (+0.5% acetic acid) extracts exhibited the highest TPC, TFC, and FRAP values for black bean, lentil, black soybean, and red kidney bean. The 80% acetone extracts exhibited the highest TFC, CTC, and DPPH-free radical scavenging activity for yellow pea, green pea, chickpea, and yellow soybean. The 70% ethanol extracts exhibited the greatest ORAC value for all selected legumes. These results indicated that solvents with different polarity had significant effects on total phenolic contents, extracted components, and antioxidant activities. High correlations between phenolic compositions and antioxidant activities of legume extracts were observed. The information is of interest to the nutraceutical food/ingredient industries since legumes are a rich source of antioxidants.

A Comparative Study on Phenolic Profiles and Antioxidant Activities of Legumes as Affected by Extraction Solvents

Being secondary plant metabolites, polyphenols represent a large and diverse group of substances abundantly present in a majority of fruits, herbs and vegetables. The current contribution is focused on their bioavailability, antioxidative and anticarcinogenic properties. An overview of extraction methods is also given, with supercritical fluid extraction highlighted as a promising eco-friendly alternative providing exceptional separation and protection from degradation of unstable polyphenols. The protective role of polyphenols against reactive oxygen and nitrogen species, UV light, plant pathogens, parasites and predators results in several beneficial biological activities giving rise to prophylaxis or possibly even to a cure for several prevailing human diseases, especially various cancer types. Omnipresence, specificity of the response and the absence of or low toxicity are crucial advantages of polyphenols as anticancer agents. The main problem represents their low bioavailability and rapid metabolism. One of the promising solutions lies in nanoformulation of polyphenols that prevents their degradation and thus enables significantly higher concentrations to reach the target cells. Another, more practiced, solution is the use of mixtures of various polyphenols that bring synergistic effects, resulting in lowering of the required therapeutic dose and in multitargeted action. The combination of polyphenols with existing drugs and therapies also shows promising results and significantly reduces their toxicity.

https://www.mdpi.com/1420-3049/21/7/901/pdf

Polyphenols: Extraction Methods, Antioxidative Action, Bioavailability and Anticarcinogenic Effects

Antioxidant activities, phenolic and β-carotene contents of sweet potato genotypes with varying flesh colours

The 80% ethanol extracts of 5 purple-fleshed sweet potato cultivars were separated into 2 fractions, anthocyanins- and phenolic compounds-rich fractions, to clarify the contribution of these constituents to the radical-scavenging activity. The separation was accomplished with an ethyl acetate liquid/liquid extraction. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity in each fraction and the contributors varied according to the cultivars. The dominant DPPH radical-scavengers in “Ayamurasaki” and “Kyushu-132” were anthocyanins rather than phenolic compounds, while those in “Miyanou-36” and “Bise” were phenolic compounds, such as chlorogenic acid. Furthermore, the high-performance liquid chromatography analysis of anthocyanins showed that “Ayamurasaki” and “Kyushu-132” were rich in anthocyanins with peonidin aglycon, whereas “Miyanou-36,”“Bise,” and “Tanegashimamurasaki” contained cyanidin aglycon.

Involvement of Anthocyanins and other Phenolic Compounds in Radical-Scavenging Activity of Purple-Fleshed Sweet Potato Cultivars

The extracts from white-, black-, and red-hulled rice were prepared by sequential extraction with six different polar solvents, and their radical-scavenging activities were measured by methods usin...

Polymeric procyanidins as radical-scavenging components in red-hulled rice.

1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity of the 70% aqueous acetone extract from the seed coat of the brown soybean variety, Akita-Zairai, was investigated The activity of the seed coat of Akita-Zairai was much higher than that of three other reddish-brown varieties, but lower than that of two black varieties, and was closely dependent on the content of phenolic compounds In the LH20 column chromatography of Akita-Zairai, high DPPH radical-scavenging activities were detected in the fractions eluted with MeOH and 70% aqueous acetone Proanthocyanidins were also detected in fractions showing high radical-scavenging activities Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis showed that the degree of polymerization (DP) of the procyanidins contained in the brown or black soybean seed coat was as high as DP30

Highly polymerized procyanidins in brown soybean seed coat with a high radical-scavenging activity.

Studies on the physiological functionality of purple-fleshed sweet potatoes and their dominant anthocyanin pigments are described. The purple-fleshed sweet potato cultivar 'Ayamurasaki' contained anthocyanins, which consisted of mono- or di-acylated forms of cyanidin (YGM-1a, -1b, -2 and -3) and peonidin (YGM-4b, -5a, -5b and -6). It was also rich in anthocyanins with peonidin aglycon. The 'Ayamurasaki' extract and the purified YGM exhibited multiple physiological functions such as radical-scavenging, antirnutagenic, angiotensin I-converting enzyme-inhibitory, and α-glucosidase-inhibitory activities in vitro. Moreover, they also showed an ameliorative effect on carbon tetrachloride-induced liver injury and decreased postprandial blood glucose levels in rats. In addition, their role in restoring the liver function and blood pressure levels to normal in volunteers with impaired hepatic function and/or hypertension was also confirmed. The acylated anthocyanins, which were the major radical scavengers in 'Ayamurasaki', were directly absorbed into the blood stream of rats and were present as intact acylated forms in the plasma, and could also enhance the plasma antioxidative capacity. Based on these evidences, the purple-fleshed sweet potato can be recommended as a superior source for the production of foods with health benefits. Some foods and beverages in Japan that utilize these characteristics of anthocyanin pigments are also introduced in this paper.

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Shu Furuta

Papers

Involvement of Anthocyanins and other Phenolic Compounds in Radical-Scavenging Activity of Purple-Fleshed Sweet Potato Cultivars

Polymeric procyanidins as radical-scavenging components in red-hulled rice.

Highly polymerized procyanidins in brown soybean seed coat with a high radical-scavenging activity.

Physiological Functionality of Purple-Fleshed Sweet Potatoes Containing Anthocyanins and Their Utilization in Foods