Natural phenolic compounds play an important role in cancer prevention and treatment. Phenolic compounds from medicinal herbs and dietary plants include phenolic acids, flavonoids, tannins, stilbenes, curcuminoids, coumarins, lignans, quinones, and others. Various bioactivities of phenolic compounds are responsible for their chemopreventive properties (e.g., antioxidant, anticarcinogenic, or antimutagenic and anti-inflammatory effects) and also contribute to their inducing apoptosis by arresting cell cycle, regulating carcinogen metabolism and ontogenesis expression, inhibiting DNA binding and cell adhesion, migration, proliferation or differentiation, and blocking signaling pathways. This review covers the most recent literature to summarize structural categories and molecular anticancer mechanisms of phenolic compounds from medicinal herbs and dietary plants.

Natural Phenolic Compounds From Medicinal Herbs and Dietary Plants: Potential Use for Cancer Prevention

This narrative mini- review summarizes current knowledge of the role of polyphenols in health outcomes-and non-communicable diseases specifically-and discusses the implications of this evidence for public health, and for future directions for public health practice, policy, and research The publications cited originate mainly from animal models and feeding experiments, as well as human cohort and case-control studies Hypothesized protective effects of polyphenols in acute and chronic diseases, including obesity, neurodegenerative diseases, type 2 diabetes, and cardiovascular diseases, are evaluated Potential harmful effects of some polyphenols are also considered, counterbalanced with the limited evidence of harm in the research literature Recent international governmental regulations are discussed, as the safety and health claims of only a few specific polyphenolic compounds have been officially sanctioned The implications of food processing on the bioavailability of polyphenols are also assessed, in addition to the health claims and marketing of polyphenols as a functional food Finally, this mini-review asserts the need for increased regulation and guidelines for polyphenol consumption and supplementation in order to ensure consumers remain safe and informed about polyphenols

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The Role of Polyphenols in Human Health and Food Systems: A Mini-Review.

USDA Database for the Flavonoid Content of Selected Foods Release 3.1

Effect of fermentation on the antioxidant activity in plant-based foods

Flavonoids are polyphenolic compounds subdivided into 6 groups: isoflavonoids, flavanones, flavanols, flavonols, flavones and anthocyanidins found in a variety of plants. Fruits, vegetables, plant-derived beverages such as green tea, wine and cocoa-based products are the main dietary sources of flavonoids. Flavonoids have been shown to possess a wide variety of anticancer effects: they modulate reactive oxygen species (ROS)-scavenging enzyme activities, participate in arresting the cell cycle, induce apoptosis, autophagy, and suppress cancer cell proliferation and invasiveness. Flavonoids have dual action regarding ROS homeostasis—they act as antioxidants under normal conditions and are potent pro-oxidants in cancer cells triggering the apoptotic pathways and downregulating pro-inflammatory signaling pathways. This article reviews the biochemical properties and bioavailability of flavonoids, their anticancer activity and its mechanisms of action.

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Flavonoids as Anticancer Agents

Interactions of polyphenols with carbohydrates, lipids and proteins

https://bib.irb.hr/datoteka/482802.eruga-FC-2011.pdf

Determination of polyphenols content and antioxidant activity of some red wines by differential pulse voltammetry, HPLC and spectrophotometric methods.

Background Polyphenolic compounds have shown many potentially positive bioactivities. But these beneficial effects depend on the amount of polyphenols accessible for absorption in the upper or lower parts of the digestive tract (bioaccessibility) or on the amount actually absorbed. Dietary fibers can interact with polyphenols in the digestive tract creating associations with them, which might influence polyphenol bioaccessibility in the digestive tract and therefore their bioactivities. Scope and approach The aim of this review is to discuss recent literature about non-covalent dietary fiber - polyphenol interactions, the parameters that affect these interactions, the types of bonds between polyphenols and dietary fibers and the influence of dietary fibers on the polyphenol bioaccessibility in the upper and lower parts of the digestive tract. Key findings and conclusions Dietary fibers create associations with polyphenols. This process depends on environmental conditions like pH value, temperature and ionic strength. In both, the upper and lower parts of the digestive tract, polyphenols can be released from various food matrices. Dietary fibers affect that process by lowering the polyphenol amount released in the upper digestive tract. By this mechanism, they also potentially increase the polyphenol amount that reaches lower parts of the digestive tract, where polyphenols, once released, can show beneficial effects. Dietary fibers might be a sort of a “control mechanism” for controlling the amount of bioaccessible polyphenols in the upper or lower parts of the digestive tract. Further studies are needed to clarify the role of dietary fibers in polyphenol bioactivities.

Non-covalent dietary fiber - Polyphenol interactions and their influence on polyphenol bioaccessibility

Red fruits (blueberry, blackberry, chokeberry, strawberry, red raspberry, sweet cherry, sour cherry, elderberry, black currant and red currant) were analyzed for flavonols (quercetin, myricetin, and kaempferol), hydroxycinnamic acids (caffeic, ferulic, p-coumaric acid) and hydroxybenzoic acids (p-hydroxybenzoic, ellagic acid) by using HPLC method. Compounds were analyzed as aglycons after acid hydrolysis with 1.2 mol dm-3 HCl. Each fruit sample was analyzed for total polyphenols (TP) and total anthocyanins (TA). TP ranged from 1763 to 7194 mg kg-1 fresh weight (FW) in red raspberries and chokeberries, respectively. TA ranged from 169 to 4069 mg kg-1 FW in strawberries and blueberries, respectively. Flavonols varied from 4 mg kg-1 in red raspberries to 183 mg kg-1 in blueberries. Hydroxycinnamic acids were found in relatively high concentrations in blueberries (92 mg kg-1) and in black currant (70 mg kg-1) and represented significant portion in sour and sweet cherry phenolics. The amount of ellagic acid was high in blackberry (121 mg kg-1), strawberry (41 mg kg-1) and red raspberry (32 mg kg-1). The strongest antioxidant activity determined by DPPH• and ABTS• + assays showed chokeberry, followed by blueberry, black currant and elderberry. Antioxidant activity correlated better with TP than with TA, total flavonols (TF), or total hydroxycinnamic acids. Additionally, linear relationship was observed between antioxidant activity of fruits and content of caffeic acid, quercetin and p-coumaric acid. Overall results showed that red fruits can serve as good source of bioactive polyphenols in human diet, but due to high concentrations of anthocyanins, flavonols, phenolic acids and strong antioxidant activity, chokeberry, blueberry, elderberry and black currant can be regarded as good candidates for nutritional supplement formulations.

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Flavonols, phenolic acids and antioxidant activity of some red fruits

#Summary Anthocyanin content and antioxidant activity of various red fruit juices (black currant, red raspberry, blackberry, sour cherry, sweet cherry, strawberry, chokeberry, and elderberry juice) has been evaluated in this study by using HPLC, pH-differential, and DPPH method. Anthocyanins were the predominant phenolic components (66 % in elderberry juice, 56 % in black currant juice) or represented considerable portion in total polyphenol content of some juices (40 % in blackberry juice, 33 % in chokeberry juice). Amount of anthocyanins determined by HPLC method ranged from 202 to 6287 mg l –1 in strawberry and elderberry juice, respectively. Anthocyanins present in investigated red fruit juices were derivatives of cyanidin, delphinidin, pelargonidin and peonidin. Chokeberry, elderberry, blackberry and sour cherry juice were characterized by cyanidin derivatives, black currant juice by delphinidin and cyanidin derivatives and strawberry juice by pelargonidin derivatives. The major anthocyanins in red raspberry and sweet cherry juice were derivatives of cyanidin although peonidin (in sweet cherry juice) and pelargonidin derivatives (in red raspberry juice) were found in low amount. Antioxidant activity varied from 4 to 72 μmol TE/ml in sweet cherry and chokeberry juice, respectively. High correlation was observed between antioxidant activity and total anthocyanin content of investigated red fruit juices. Overall results showed that red fruit juices can serve as a good source of bioactive phytochemicals in human diet. Chokeberry, elderberry and black currant juice were the richest in anthocyanin content and showed the strongest antioxidant activity, as well. Therefore, these three juices can be regarded as good candidates for raw materials in production of functional foods. Zusammenfassung In dieser Studie wurden Anthocyane-Konzentration sowie antioxidative Aktivitat von Fruchtsafte aus verschiedenen Beerenfruchte-Sorten und Kirschen (schwarze Johannisbeere, Himbeere, Brombeere, Sauerund Suskirschen, Erdbeere, Aronia und Holunderbeere) mittels HPLC, pH-Differenzial und DPPH-Methode bestimmt. In einigen Saften bilden Anthocyane den grosten Anteil der Gesamtpolyphenole (z. B. 66 % im Holunderbeersaft, 56 % im schwarzen Johannisbeersaft), oder stellen einen bedeutenden Anteil am Gesamtpolyphengehalt mancher Safte (40 % im Brombeersaft, 33 % im Aroniasaft) dar. Die Anthocyane-Konzentration, mittels HPLC bestimmt, variierte von 202 mg/l im Erdbeersaft bis 6287 mg/l im Holunderbeersaft. Bei den aus Beerenfruchten und Kirschen hergestellten Fruchsaften vorhandenen Anthocyanen handelt es sich um Cyanidin-, Delphinidin-, Pelargonidin-, und Peonidinderivate. So wurden im Aronia-, Holunderbeere-, Brombeere- und Sauerkirschensaft Cyanidinderivate gefunden. Im schwarzen Johannisbeersaft wurden Delphinidin- und Cyanidin-, im Erdbeersaft Pelargonidinderivate gefunden. Die im Himbeer- und Suskirschensaft enthaltenen Anthocyane sind grostenteils Cyanidinderivate, obwohl auch darin, aber nur in kleinen Mengen, Peonidinderivate (im Suskirschensaft) und Pelargonidinderivate (im Himbeersaft) vorhanden sind. Die antioxidative Aktivitat variierte im Bereich von 4 μmol Troloxaquivalent/ml im Suskirschensaft bis zu 72 μmol Troloxaquivalent/ml im Aroniasaft. Es wurde eine starke Korrelation zwischen der antioxidativen Aktivitat und der Anthocyan-Konzentration in den gepruften Saften aus Beerenfruhten und Kirschen festgestellt. Alle Ergebnisse weisen darauf hin, dass Safte aus Beerenfruchten und Kirschen eine geeignete Quelle an bioaktiven Phytochemikalien fur die menschliche Ernahrung darstellen. Aronia-, Holunderbeer- und schwarzer Johannisbeersaft enthalten die groste Anthocyane-Konzentration und zeigen die starkste antioxidative Aktivitat. Diese Safte sind daher zur Herstellung funktioneller Lebensmittel geeignet.

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Lidija Jakobek

Papers

Interactions of polyphenols with carbohydrates, lipids and proteins

Determination of polyphenols content and antioxidant activity of some red wines by differential pulse voltammetry, HPLC and spectrophotometric methods.

Non-covalent dietary fiber - Polyphenol interactions and their influence on polyphenol bioaccessibility

Flavonols, phenolic acids and antioxidant activity of some red fruits

Anthocyanin content and antioxidant activity of various red fruit juices