Month: November 2019

2,4,6-trihydroxyphenanthrene: a new trans-resveratrol derivative detected in red wine after UV irradiation.

By Luciana Mosca and Alberto Macone

RSV is a naturally occurring compound produced by plants in response to biotic and abiotic stress, including pathogenic invasion, physical trauma and UV irradiation and occurs in two isomeric forms, cis- and trans-RSV, the latter being dominant in terms of prevalence and biological activity.
RSV can be found as a glucoside derivative in many plant foods (red grapes, berries, peanuts, soy, etc.), while in red wine it is mainly present as an aglycone derivative. Resveratrol content in red wine comes from grapes (Vitaceae), being the skin, seeds, petioles, and woody parts the richest sources. Even though the direct free radical scavenging activity of resveratrol is relatively poor, in vitro, ex-vivo and in vivo experiments show that its antioxidant properties are likely due to its effect as a gene regulator. Thus, it is not surprising that this molecule may affect many cellular processes including metabolism, stress resistance, cell survival, aging inflammation and immune response. However, although commonly used as a dietary supplement, and despite the number of beneficial effects described over the years, there is little clinical evidence that RSV could be an effective therapeutic agent in humans. Similarly, very little is known about the effects of RSV derivatives (synthetic and natural analogues as well as adducts, derivatives, and conjugates) on human health and only a few studies have been set up to determine the levels of the other stilbenes in wines, with the exception of the cis-RSV, and their 3-O-β-glucosides.
Recently we have focused our attention on resveratrol photo-oxidation products. It is known that, when exposed to UV radiation, trans-RSV isomerizes to cis-RSV. The latter can subsequently undergo electrocyclization leading to the formation of THP (Figure 1).

 

Figure 1. UV light induced photo-oxidation of trans-RSV.

To the best of our knowledge, THP has not yet been detected in RSV rich foods or in beverages such as red wine. Considering that red wine is the main source of trans-RSV, and the cis-isomer can be formed in this matrix as the result of UV-light induced isomerization, it is reasonable to hypothesize the presence of THP as well.
In our laboratory, at Sapienza University, we set up a simple procedure for the simultaneous qualitative and quantitative analysis of trans-RSV, cis-RSV and THP in red wine, before and after UV-light exposure. Being these molecules sparingly soluble in water, we performed a liquid-liquid extraction using ethyl-acetate. The organic extracts were then submitted to a derivatization procedure in order to make RSV isomers and THP suitable to the subsequent gas chromatographic-mass spectrometric analysis.
In setting up and validating the analytical method, we had to solve two different critical issues: i) cis-RSV and THP are not commercially available (this represents one of the major limits to the studies on these molecules); ii) due to the complexity and the natural variability of wine chemical composition, the validation of the analytical method should be done on an artificial matrix (synthetic wine) that can resemble, as much as possible, a generic red wine.
To solve this latter issue, we prepared and used for the validation of the analytical method a synthetic red wine consisting in a water solution containing 13% ethyl alcohol, 1% glycerol and a variety of acids, such as succinate, malate and tartrate (making up an additional 0.8%) at a final pH of 3.3.
Concerning the issue arising from the lack of commercially available analytical standards, cis-RSV can be easily prepared by exposing trans-RSV dissolved in isopropanol or methanol to sunlight or UV light. However, in these conditions, the subsequent rate of conversion of cis-RSV to THP is very low. We were able to show that when the UV irradiation is performed in ethanol-water solution (13:87 v/v), higher rate of conversion of cis-RSV to THP can be achieved. This procedure yields cis-RSV and THP directly from trans-RSV at concentrations suitable to setting-up the analytical method. Thus, by varying the exposure time to UV light, it is possible to fine-tune the relative concentrations of RSV isomers and THP.
Once developed and fully validated, the analytical method was then tested on a selection of commercial and homemade red wines from different Italian regions, grape varieties and vintages showing for the very first time the presence of THP in this matrix.
These wines were analyzed before and after 10 min of UV irradiation. As expected, UV light induces trans-RSV isomerization followed by cis-RSV cyclization to THP. After only 10 min of UV light treatment, a mean 9.35-fold increase of THP can be observed (Figure 2). The studies on THP are in the early stages and, at present, the potential effects of this molecule on human health are not yet known. Being a polycyclic aromatic hydrocarbon, THP could indeed exert cytotoxic and genotoxic effects. It has been demonstrated that THP can induce DNA damage through a pro-oxidant mechanism on Caulobacter crescentus model system, even at sub-micromolar concentrations. On the other hand, due to the extended delocalization and conjugation of the π electrons over the entire molecule, THP displays a significantly increased antioxidant activity compared to RSV with potential benefits on human health.
Whatever the effect of THP on human health, it becomes important to establish its actual presence not only in RSV-containing food and beverages but even in cosmetics that, by their nature, are subject to UV radiation.

Figure 2. THP mean value in 20 different Italian wines before and after UV treatment

Dr Alberto Macone: master degree in Biological Sciences, residency in Clinical Pathology and Ph.D. in Biochemistry. Currently, he is assistant professor at the Department of Biochemical Sciences “A. Rossi Fanelli, Sapienza University of Rome (Italy) where he is head of the Metabolomics Lab. His research activity is mainly focused on metabolome analysis (metabolite target analysis, profiling and fingerprinting) through the development and validation of chromatographic and mass spectrometric methods for the study of metabolic profiles associated with specific cellular processes, physiological and pathological, in different biological systems. Part of the research work is dedicated to plant metabolomics (biochemical characterization of plant pathogen interaction) and to the application of metabolomics to food quality and safety.

mail: alberto.macone@uniroma1.it
ORCID ID: 0000-0003-0455-1400
ResearcherID: AAB-2570-2019

 

Dr. Luciana Mosca: master degree in Pharmacy, PhD in Biochemistry, residency in Human Nutrition and master in Clinical Research. Currently she is Assistant Professor at the Department of Biochemical Sciences, Sapienza University of Rome. She has a longstanding experience in the field of oxidative stress and free radicals. She focuses on the mechanisms behind oxidative stress triggers of cell death in neurodegenerative diseases and on the identification of natural substances able to counteract this phenomenon. Particularly, bioactive polyphenols isolated from foods rich in antioxidants, from spices or from medicinal plants are the main object of her interest. She is author of more than 60 papers on peer reviewed international journals and of 5 book chapters. She holds two patents as inventor. She teaches biochemistry and nutritional biochemistry in pre- and post-graduation courses.

Mail: luciana.mosca@uniroma1.it
ORCID ID: 0000-0003-2748-9021
Researcher ID: K-8101-2015

 

References

“Gas chromatographic-mass spectrometric method for the simultaneous determination of resveratrol isomers and 2,4,6-trihydroxyphenanthrene in red wines exposed to uv-light”.
Francioso A, Laštovičková L, Mosca L, Boffi A, Bonamore A, Macone A. J Agric Food Chem. 2019, 67,11752-11757. doi: 10.1021/acs.jafc.9b05992.

“Isolation and identification of 2,4,6-trihydroxyphenanthrene as a byproduct of trans-resveratrol photochemical isomerization and electrocyclization”.
Francioso A, Boffi A, Villani C, Manzi L, D'Erme M, Macone A, Mosca L. J Org Chem. 2014, 79, 9381-4. doi: 10.1021/jo501405m.

“2,4,6-Trihydroxyphenanthrene, a trans-resveratrol photoreaction byproduct: first evidences of genotoxic risk”.
Francioso A, Mosca L, Menéndez-Perdomo I.M, Fanelli S, Fontana M, D'Erme M, Fuentes-Leon F, Sanchez-Lamar A. Phytochem. Lett. 2019, 30, 362-366.

“Synthesis and antioxidant activity of hydroxylated phenanthrenes as cis-restricted resveratrol analogues”.
Ding D.J, Cao, X.Y, Dai, F, Li X.Z, Liu G.Y, Lin D, Fu X, Jin X.L, Zhou B. Food Chem. 2012, 135, 1011-9. doi: 10.1016/j.foodchem.2012.05.074.

Posted by in Chemistry, Health

How efficient is resveratrol as an antioxidant of the Mediterranean diet, towards alterations during the aging process?

By Paula Silva, Antoni Sureda, Josep A. Tur, Pierre Andreoletti, Mustapha Cherkaoui-Malki and Norbert Latruffe

Mediterranean diet (MD) is the most relevant nutritional aspect of the multisecular Mediterranean civilisation which includes wine as an element of health and wellbeing when consumed with moderation. Indeed, besides macronutrients (protein, carbohydrates, and lipids), Mediterranean meals provide food micronutrients which include polyphenols, vitamins, fibres, polyunsaturated fatty acids, and oligo-elements brought by fruits, vegetables, olive oil, fish, infusions, wine, and others. Interestingly, grape and olives provide unique polyphenols with antioxidant properties, especially resveratrol from grapes and red wine.
This review topic deals with how efficient is resveratrol (RSV) towards alterations during the aging process, as protective agent of brain aging on the elderly. MD, also called Cretan diet, has been proven to prevent diseases including cardiovascular pathologies and to prevent aging. The highest level of centenarian is found in countries where they adopt MD and a good life style i.e. in Crete, Sardinia, and in other places of Mediterranean coast. By the way, this diet can be compared to the Okinawa diet which privileges omega-3 fatty acid, polyphenols from seaweed and from tea.
Impairment of the nervous system in different regions of the brain occurs mostly in aging people leading to neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease (PD), and multiple sclerosis, which are the most common. Aging cognitive impairment is considered to be associated with increased oxidative stress and the well-known antioxidant properties of dietary RSV appear interesting to explore. The published data are often surprising. For instance, consumption of RSV capsules enhances both cerebrovascular function and cognition in postmenopausal women. In contrast, for some reviews and meta-analysis, RSV has no significant effect on memory improvement or cognitive performance. The contradictory results obtained with different antioxidants, and in our case with resveratrol derives from their capability to exert pro-oxidant and antioxidant activities of resveratrol depending on its concentration and the target cell type.

 

Figure 1. Effect of resveratrol (RSV) on signalling pathways involved in LPS (or Ab)-induced inflammation in microglial cells.

The beneficial effects of RSV associated with the practice of physical exercise are not clear either. Although there is some evidence of beneficial effects, RSV counteracts its positive effects. At the opposite, supplementation with RSV augmented the improvement of mitochondrial function, muscle fatigue resistance, and the increased mean fibre area and muscle nuclei associated with exercise, which may contribute to reducing/reversing sarcopenia in elderly people. In the PREDIMED study, the authors also described the inverse association between high levels of RSV and the risk of developing frailty syndrome during the first 3 years of follow-up, but no significant effects were found after 6 and 9 years.
The apparent inconsistent results in cognitive improvement or not are summarised here: RSV nutritional interventions lead to an increase in brain functions, cerebral blood flow of healthy adults without affecting their cognitive function. While no improvement in verbal memory was observed in elderly people after receiving RSV, the consumption of RSV enhances both cerebrovascular function and cognition in postmenopausal women. In addition, meta-analysis considers that RSV has no significant effect on memory improvement or cognitive performance. The possible reasons for these discrepancies could be due to variations in the protocol of RSV administration and the patient status.
Moreover, in some aging disorders, oxidative stress and neuro-inflammation, associated with microglia activation play a central role in the physiopathogenesis by producing proinflammatory molecules. Anti-inflammatory diet components such as RSV exhibit basic mechanisms leading to protecting effects, at least in biological models.
RSV is thus a molecule capable of acting in various cell types of the eye by increasing the level of natural antioxidant defences and to limit the generation of free radicals and the onset of irreversible damage, initiators of diseases such as AMD, cataracts, or glaucoma.

Figure 2. Possible preventive effect of resveratrol (RSV) on the pathogenesis of wet age-related macular degeneration.

In conclusion, only a few controlled studies on RSV were done so far. The evidence is based on animal research and first interventional human trials warrant further investigations. The MD concept of food synergy should benefit from future trials that evaluate the basic knowledge of lifestyle patterns to prevent declining cognitive functions with the aging process.

Read all this paper at: https://www.tandfonline.com/doi/full/10.1080/10715762.2019.1614176

Posted by in Health

Post Nº 100

By Paula Silva

100. This is the POST number 100. Since January 22 of 2018 that each Sunday a new post was published in Science & Wine blog. When I started this project, my closest friends considered my intention of posting with a week periodicity very ambitious. This was only possible because many scientists shared their research and contributed with a post. In my opinion, this is a sign that academics are becoming increasingly aware of the importance of communicating their scientific results with a non-academic audience through social media. This mindset change is very important to increase scientific literacy. The number of people that use the web to learn new things are increasing. People believe that internet helps them to stay better informed and increases their capacity to share ideas and creations with others. On other hand, we all know that online misinformation is also increasing. Researchers must help to stop the spread of false information by feeding these media with information of quality.

Non-scientist people do not look for information in scientific journals.

Post authors of Science & Wine blog.

Wine blog subscribers and of Facebook, Twitter and Instagram followers are increasing in a sustainable way, which gives me the hope that people who look for it are really interested in the information provided. Thanks to all the researchers that already contributed, and I hope that much follow their example.

But the blog is only one of the tools used by Science & Wine to communicate scientific information. In this post I highlight the Wine Science Cafés and the Scientific Meetings. Next December 13th will happen the last Wine Science Café of 2019 in Quinta do Soalheiro. This will be the tenth event organized by us aimed to encourage conversation, debate, interaction, and dialogue between scientists and the public. In 2019 we also promoted The First Science & Wine World Congress planned to be a discussion forum considering the wide wine research spectrum. The idea attracted more than 100 attendees most of which scientists. Among the topics discussed, the effects of wine in health was pointed out as a priority. Therefore, we are planning for 2020 1-Day Conference “Wine Consumption in the Mediterranean Diet: A clarification about health effects” that will be held in Porto at June 4 in AEVP. We are all invited to participate in our events.

Wine sector progress can be effective only with the wine professional’s active involvement.

Is it possible to do more? Yes, it is, much more. One of Science & Wine priorities is to create an online app aimed to facilitate the link between who want a work opportunity in wine sector and the enterprises, vice versa. The idea is to have a “tinder” app where wine enterprises and young people who want to work in this sector can find the best match based on profile defined by the other part. And what about a Science & Wine podcast in Portuguese? But to continue with Science & Wine projects is fundamental the support of our partners. This post is also my tribute to all that help us to make this project possible.
Thank you for following and support Science & Wine.

Young people play a crucial role as key designers of the future of wine sector.

Posted by in Chemistry, Curiosities, Economy | Marketing, Enology, Food Science and Technology, Health, History, Nutrition, Viticulture