The wine industry represents a significant economic sector; however, it generates large volumes of waste that can be valorized due to the presence of bioactive compounds, particularly stilbenes. These naturally occurring stilbenes exhibit remarkable potential in the prevention and treatment of various diseases, including cardioprotection, neuroprotection, antidiabetic properties, anti-inflammatory activity, and cancer prevention and therapy. This review discusses biosynthesis, structures, extraction methods, and mechanisms of action of stilbenes, with a particular emphasis on cancer prevention and treatment. Evidence from in vitro, in vivo, and clinical studies demonstrate that stilbenes modulate multiple molecular pathways by promoting apoptosis, inhibiting cell proliferation, and regulating inflammation, oxidative stress, and metabolism. However, the clinical application of stilbenes is limited by their low bioavailability. To overcome this, pharmaceutical formulations have been developed to enhance their stability and bioavailability, reduce side effects, and improve target interactions. These advances are expected to increase the therapeutic efficacy of stilbenes. Furthermore, information on the health benefits of less common stilbenes remains limited, highlighting the need for further research on these compounds.

BACKGROUND Resveratrol (3,5,4′‐trihydroxy‐trans‐stilbene) is a natural phytoalexin synthesized by plants in response to stress. This compound has several beneficial documented properties, namely anti‐inflammatory, antioxidant, neuroprotective and antimicrobial activities. In this study the antimicrobial activity of resveratrol against Listeria monocytogenes and Listeria innocua was investigated. RESULTS Resveratrol had a minimum inhibitory concentration of 200 µg mL−1 for the tested strains, with time‐kill curves demonstrating bacteriostatic activity. Inhibition of biofilm formation was also assessed, with resveratrol strongly inhibiting biofilm formation by both species even at subinhibitory concentrations. Overall, resveratrol showed antimicrobial properties on planktonic cells and on biofilm formation ability. Considering the potential use of resveratrol as a food preservative, the antimicrobial efficacy of resveratrol in food was studied in milk, lettuce leaf model and chicken juice. Resveratrol retained greater efficacy in both lettuce leaf model and chicken juice, but milk had a negative impact on its antilisterial activity, indicating a possible reduction of resveratrol availability in milk. CONCLUSION This study reinforces resveratrol as an antimicrobial agent, pointing out its antibiofilm activity and its potential use as preservative in some food matrices. © 2016 Society of Chemical Industry

Os compostos polifenólicos são um grupo de metabolitos secundários que ocorrem na Natureza. São considerados compostos bioativos pois apresentam múltiplas propriedades biológicas e farmacológicas, entre elas destaca-se a atividade antioxidante. A sua aplicação é reduzida devido à sua baixa solubilidade em água, fraca absorção intestinal e estabilidade limitada. A polidatina é um derivado glicosilado do resveratrol com uma grande variedade de actividades biológicas descritas em diversos estudos in vitro e in vivo.A modificação semi-sintética dos compostos polifenólicos glicosilados através da obtenção de derivados acilados visa melhorar as caraterísticas físico-químicas dos compostos e explorar a modulação das suas actividades biológicas. A acilação enzimática seletiva destes compostos é preferível em relação à catálise química, uma vez que se trata de moléculas complexas e lábeis, sendo necessárias reações seletivas e condições suaves, condições estas não oferecidas pela catálise química. Além disso, por via enzimática, as etapas de proteção /desproteção dos grupos funcionais são evitadas, reduzindo os passos de síntese. Tendo em consideração as vantagens que oferece a biocatálise, esta parece ser uma estratégia eficaz para a modificação estrutural dos compostos polifenólicos.De forma a melhorar as propriedades biológicas e farmacológias da polidatina, um derivado glicosilado do resveratrol, este trabalho teve como objetivo geral a obtenção de derivados acilados da polidatina através da biocatálise, recorrendo à lipase B de Candida antarctica (CALB) como biocatalisador. Neste trabalho estudou-se a síntese e caraterização estrutural de derivados acilados da polidatina, onde pela análise dos espetros de ressonância magnética nuclear foi possível verificar as posições de acilação da polidatina, bem como confirmar a estrutura dos derivados acilados obtidos.

Aiming at the development of an active food packaging, the goal of this study was to increase stilbenes (resveratrol (RV), pterostilbene (PT) and pinosylvin (PS)) aqueous solubility and stability using hydropropyl-cyclodextrins (HP-CDs) and bile salts. To evaluate stilbene concentration, an HPLC-DAD method was validated. Stilbene solubility was improved by the formation of inclusion complexes and micellar systems with higher solubility values obtained for the inclusion complexes with cyclodextrins. Inclusion complexes revealed a 1:1 stoichiometry for RV and PT and a 1:2 for PS. Solid state characterisation was carried out using X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry. 1H NMR studies were also performed to characterise the prepared complexes. Photostability studies revealed that CDs were able to increase stilbene photostability at 4 °C. This work showed that stable stilbene solutions can be achieved using hydroxypropyl-CDs, contributing for their incorporation in several materials for the food and pharmaceutical industries.

This study presents a sustainable method to purify stilbenes from residual grape stem biomass. This approach was experimentally validated through the use of a pilot size fixed-bed adsorption prototype for the automation of the purification process. Molecularly imprinted polymers, synthesized through photopolymerization at room temperature and incorporating the 4-vinylpyridine monomer, serve as adsorbents. The purification procedure leads to a significant enrichment, with a more than 22-fold increase in (E)-ε-viniferin and a 9-fold increase in (E)-resveratrol. High recoveries of 80.3% and 62.1% for (E)-ε-viniferin and (E)-resveratrol, respectively, were achieved. Notably, the use of eco-friendly water and ethanol mixtures distinguishes this method from others focused on stilbenes purification. This study further explores the variability of the stilbenes in the residual grape stems by analysing different varieties, emphasizing the complexity of the starting material of the purification process. The range of purities achieved for the fractions enriched with stilbenes (e.g., 12.8% for (E)-ε-viniferin and 3.4% for (E)-resveratrol) are suitable for direct use in controlling of Plasmopara viticola, the agent causing grapevine downy mildew. Furthermore, through compositional combination of these fractions, it is possible to conceive new stilbene-containing phytochemicals with improved anti-fungal activity. Therefore, the developed adsorbents and purification process, enabling the steady enrichment of stilbenes regardless of the unavoidable variability in the initial vine biomass, is a contribution towards the quest for more environmentally friendly and sustainable phytochemicals.

The selective separation of structurally analogous polyphenols from complex plant matrices remains a longstanding challenge in bioseparation engineering. This study introduces a custom-designed adsorbent, poly(2,6-bis(acrylamido)pyridine) (poly(BAAPy)), tailored for subfamily-level resolution of stilbenes obtained from crude grape cane extracts. Leveraging dual amide and pyridine functionalities, poly(BAAPy) achieves selective retention of oligomeric stilbenes (e.g., trans-ε-viniferin, miyabenol C) via multivalent hydrogen bonding and π-π stacking interactions. Comparative breakthrough experiments against commercial poly(4-vinylpyridine) (poly(4VP)) demonstrate superior oligomer retention across both ethanol-water and acetonitrile systems. In dynamic closed-loop adsorption mode, poly(BAAPy) enabled polarity-driven elution and achieved up to a 3.4-fold enrichment of stilbene oligomers, with their recovery in fractions containing ≥ 90 % oligomeric content in a single desorption cycle. Uptake profiles and adsorption selectivity coefficients confirmed poly(BAAPy)’s preference for oligomers under both ethanol-water and acetonitrile conditions. The total stilbene recovery was 75 %. Breakthrough data were fitted using both empirical (Clark, Thomas) and mechanistic models, revealing distinct adsorption dynamics for poly(BAAPy) versus a commercial poly(4VP) resin. This work demonstrates a sustainable valorisation route for grape cane waste, converting viticultural residues into a high-value source of bioactive compounds. The use of green solvents and fixed-bed adsorption aligns with circular economy principles and environmentally conscious separation processes.

Recently, studies on the by-products from the food industry, such as passion fruit seeds, have significantly increased, as these can have an added value, due to their properties, such as potential antioxidant activity. This study was conducted to determine the presence of piceatannol and resveratrol in various extracts of passion fruit (Passiflora edulis) seeds from Madeira Island and a commercial passion fruit oil was used as reference. The commercial oil and the extracts that were obtained by traditional Soxhlet method with ethanol and acetone did not reveal the presence of the two stilbenes, piceatannol and resveratrol. However, the extracts that were obtained by the ultrasound method showed significant amounts of piceatannol and resveratrol when compared with the commercial oil. The presence of these compounds indicates that this oil could have potential application in cosmetic and pharmaceutical industries, due to their proven antioxidant and anti-aging properties.

Epidemiological studies have remarked the beneficial role that polyphenols may have in the elderly population such as cancer and cardiovascular disease prevention. This is particularly relevant considering the global tendency of population aging. Data on polyphenol intake in the elderly population are scarce and usually provide partial information—only for some polyphenol classes. The aim of this study was to estimate the intake of polyphenols and its major dietary contributors in the population of Viçosa.A cross-sectional population-based survey including 620 elderly was conducted in Viçosa, Brazil. Food intake was estimated by recall of habitual consumption (RHC). Polyphenol intake was calculated by matching food consumption data from the RHC with the polyphenol content in foods listed in the Phenol-Explorer database.The average total polyphenol intake was 1198.6 mg/day (533.7 mg/day as aglycone). The main polyphenol classes were phenolic acids (729.5 mg/day) and flavonoids (444.7 mg/day). The main dietary contributors for total polyphenols were coffee (45.8%), beans (32.8%) and polenta (1.3%). A total of 292 polyphenols divided in 14 classes and 23 subclasses were found. The individual compounds with the highest intake were isomers of chlorogenic acid (i.e., 5-caffeoylquinic acid, 4-caffeoylquinic acid and 3-caffeoylquinic acid) among hydroxycinnamic acids that largely originated from coffee.The data reported here can be used to evaluate the association between the amount and type of ingested polyphenols and health outcomes in epidemiological studies in order to eventually establish nutritional recommendations.

Polyphenols are extensively distributed in fruits, vegetables, herbs, seeds, cereals and beverages. Among the polyphenols present in foods, quercetin (QUE) and resveratrol (RES) have received increased interest because of the strong evidence of the association of their intake with a variety of health benefits. QUE is one of the largest representatives of the class of flavonoids found naturally in apples and red wine, while RES is the main representative of the class of stilbenes, naturally present in bark and grape seeds, and in wine. However, the benefits of ingestion of polyphenols are related to their bioavailability, which is usually very low. Thus, the compounds reach the large intestine, where they are metabolized through the action of the bacteria present in the intestinal microbiota. Among these bacteria potentially capable of metabolizing polyphenols are probiotics. The potential ability of probiotics to exert health benefits on the host has been commonly associated with the compliance of in vitro pre-requisites that include a set of physiological functionalities (e.g., acid and bile salts tolerance, cell surface hydrophobicity, autoaggregation, coaggregation with pathogens and antagonistic activity against pathogens) and capability of surviving during exposure to gastrointestinal conditions. Studies have suggested that the combined intake of polyphenols and probiotics may be an effective strategy to increase their biological functionalities, but phenolic compounds may exert varied influences on specific characteristics of probiotic, which reveals the need for further studies evaluating these potential influences that polyphenols may exert on probiotics. This study assessed the effects of polyphenols QUE and RES on the growth and some in vitro functionality-related properties of six proven potentially probiotic Lactobacillus strains (L. plantarum 49, L. plantarum 53, L. paracasei 106, L. paracasei 108, L. fermentum 263 and L. fermentum 296). QUE and RES showed weak inhibitory effects on the growth of the tested Lactobacillus strain, with minimum inhibitory concentration (MIC) as high as 512 – >1024 μg/mL. In most cases, QUE and RES at all tested concentrations (i.e., MIC, 1/2 MIC and 1/4 MIC) did not affect the tolerance of the Lactobacillus strains to acidic pH and bile salts. QUE increased the cell surface hydrophobicity of most of the tested Lactobacillus strains, while increases or decrease in this property varied among some of these strains in the presence of different RES concentrations. QUE and RES increased the ability of the tested Lactobacillus strains to aggregate and coaggregate with Listeria monocytogenes and Escherichia coli. These compounds did not affect negatively the antagonistic activity of the tested Lactobacillus strains against pathogens, as well as did not decrease their survival when exposed to an in vitro digestion. In few cases, the ability of some of the tested Lactobacillus strains to antagonize pathogens as well as to survive to specific steps of the in vitro digestion were increased by QUE or RES. The combined use of QUE or RES with probiotic lactobacilli could improve functional properties exerted by these bacteria on the host; however, the concentration of these compounds should be careful considered to reach these desirable effects.