Pharmacological Properties of Polyphenols: Bioavailability, Mechanisms of Action, and Biological Effects in In Vitro Studies, Animal Models, and Humans

Abstract

Drugs are bioactive compounds originally discovered from chemical structures present in both the plant and animal kingdoms. These have the ability to interact with molecules found in our body, blocking them, activating them, or increasing or decreasing their levels. Their actions have allowed us to cure diseases and improve our state of health, which has led us to increase the longevity of our species. Among the molecules with pharmacological activity produced by plants are the polyphenols. These, due to their molecular structure, as drugs, also have the ability to interact with molecules in our body, presenting various pharmacological properties. In addition, these compounds are found in multiple foods in our diet. In this review, we focused on discussing the bioavailability of these compounds when we ingested them through diet and the specific mechanisms of action of polyphenols, focusing on studies carried out in vitro, in animals and in humans over the last five years. Knowing which foods have these pharmacological activities could allow us to prevent and aid as concomitant treatment against various pathologies.

In Vitro and In Silico Interaction Studies with Red Wine Polyphenols against Different Proteins from Human Serum

“…Only an ethanolic solution of rutin at the concentration of 830 µM prolonged the aPTT, while the TT and PT were unaffected [69]. According to the results obtained and based on numerous recent reports [7,[66][67][68][69], it was declared that wines possess a high bioactivity that allows them to be settled in the industries of food additives and medicinal products. In addition to phenolics, a number of other compounds are responsible for the quality of wine, as they determine the overall organoleptic impression of the wine in addition to the content of phenolic compounds, which are also present in large amounts in many other food products.…”

“…As discussed, polyphenols are among the molecules with pharmacological activity produced by plants. As drugs, these, due to their molecular structure, also have the ability to interact with molecules in our body, presenting various pharmacological properties [66]. Tannic acid and flavonoids play a role in the prevention of some diseases, and specifically in atherosclerosis.…”

A Peek into Pandora’s Box: COVID-19 and Neurodegeneration

“…In recent years, there has been increasing data for the effectiveness of natural extracts such as polyphenols, flavonoids, and saponins as potent anti-oxidant and anti-inflammatory agents (reviewed in: [ 250 ]). Phytochemicals such as resveratrol, curcumin, mulberry extract, green tea polyphenols, etc., have been shown to energize mitochondria through the SIRT1/PGC-1α, AMPK/PGC-1α, or Nrf2/PGC-1α axis, and exert neuroprotective effects and improve overall health [ 251 , 252 , 253 , 254 , 255 ]. The therapeutic potential of thymoquinone, a component of Nigella sativa , against COVID-19 is worthy of further investigation due to multiple evidence of this compound’s efficacy in targeting the AMPK/PPARγ/PGC-1α and Nrf2/heme oxygenase (HO-1) pathway and in preventing SARS-CoV-2 entry into the cells [ 256 , 257 , 258 ].…”

All Polyphenols Are Not Created Equal: Exploring the Diversity of Phenolic Metabolites

“…The structure−activity relationships in regard to their specific biological activities among the discussed polyphenols are extensive and cannot be reviewed here in full detail; see elsewhere. 102 We can speculate that if metabolism of anthocyanins is confirmed to produce larger amounts of benzoic acid metabolites, their biological activity may be greater in the areas of inflammation via inhibition of cyclooxygenase-mediated prostaglandin formation and NADPH oxidase activities as evident from studies on salicylic acid (2HBA) and apocynin (acetovanillone). 103 Along the same line of thought, higher amounts of cinnamic acid metabolites associated with caffeoylquinic metabolism may promote greater vasodilation and blood pressure as shown for ferulic acid, 104 similar to flavan-3-ol metabolites (γ-valerolactones) and their effects on endothelial function and flowmediated dilation.…”

“…The structure–activity relationships in regard to their specific biological activities among the discussed polyphenols are extensive and cannot be reviewed here in full detail; see elsewhere . We can speculate that if metabolism of anthocyanins is confirmed to produce larger amounts of benzoic acid metabolites, their biological activity may be greater in the areas of inflammation via inhibition of cyclooxygenase-mediated prostaglandin formation and NADPH oxidase activities as evident from studies on salicylic acid (2HBA) and apocynin (acetovanillone) .…”