Liquorice compounds show dual anti-cancer and anti-inflammatory properties

Graphical abstract: Inhibitory effects of 1,3-bis-(2-substituted-phenyl)-propane-1,3-dione, β-diketone structural analogues of curcumin, on chemical-induced tumor promotion and inflammation in mouse skin‘Dibenzoylmethanes (DBMs), isolated from liquorice, have excellent anti-inflammatory and anti-cancer effects,’ claim scientists in Taiwan and the US.

DBMs are β-diketone structural analogues of curcumin and have an aspirin-like skeleton. Curcumin and aspirin are known to possess anti-inflammatory and chemopreventive effects through suppression of COX-2 gene expression.  Due to the structural similarities between DBM and curcumin and aspirin, Chuan-Chuan Lin and co-workers tested the anti-inflammatory and anti-cancer effects of DBMs. They found DBMs to have the potential to substitute for aspirin in therapeutic anti-inflammation treatment. In addition, they also noted the DBMs activities as an anticancer agent.

The team from the China University of Science and Technology and the State University of New Jersey in the US believes that DMBs acts by inhibiting the COX-2 enzyme. It is known that expression of COX-2 is associated with chronic inflammation and epithelial carcinogenesis. The team used the tumour promoting agent 2-O-Tetradecanoylphorbol-13-acetate (TPA), which induces COX-2 expression causing tumours and ear edema in the skin of mice. Lin et al. found that DBMs inhibited TPA-induced skin tumours significantly and that some of the DMB compounds possessed superior anti-inflammatory properties than aspirin. 

Read more about this paper here:
Inhibitory effects of 1,3-bis-(2-substituted-phenyl)-propane-1,3-dione, β-diketone structural analogues of curcumin, on chemical-induced tumor promotion and inflammation in mouse skin
Chuan-Chuan Lin, Yue Liu, Chi-Tang Ho and Mou-Tuan Huang
Food Funct., 2011, Advance Article
DOI: 10.1039/C0FO00098A, Paper

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Probiotics may boost cancer-preventive properties of broccoli

Food & Function paper on  gut bateria activation of broccoli’s cancer preventive agent has been highlighted in The Independent and  the Montreal Gazette.

In this paper, the US scientists from the University of Illinois have discovered that the microbacteria in the lower gut can break down glucoraphanin, present in broccoli, to its bioactive anticancer agents, sulforaphane and its metabolites. 

Sulforaphane also has anti-inflammatory properties and is able to counter the effects of many of the chronic diseases that accompany obesity and aging.

In a recent press release, Michael Miller, who is one of the co-authors of the work, suggests two ways bacteria in the colon could be manipulated to get a boost out of broccoli. “One way might be to feed the desirable bacteria with prebiotics like fiber to encourage their proliferation. Another way would be to use a probiotic approachcombining, say, broccoli with a yogurt sauce that contains the hydrolyzing bacteria, and in that way boosting your cancer protection”, says Miller.

Read the exciting article now:
Glucoraphanin hydrolysis by microbiota in the rat cecum results in sulforaphane absorption
Ren-Hau Lai, Michael Miller and Elizabeth Jeffery
Food Funct., 2010, DOI:10.1039/C0FO00110D

Read the press coverage:

Probiotics in yogurt boost benefits of broccoli

Scientists work to boost broccoli’s cancer battling abilities

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How does green tea regulate blood sugar level?

 

New insights into the effect of green tea on the molecular mechanisms of glucose metabolism have recently been reported by Hitoshi Ashida and colleagues.

Tea is one of the world’s most popular beverages and due to its content of polyphenols, particularly catechins, it is considered to possess health promoting effects.  Hitoshi Ashida and his team in Japan have previously showed that catechins in tea decrease glucose uptake in adipose tissue.

In adipose tissue, a membrane protein, GLUT4 is responsible for glucose uptake from the bloodstream.  In the absence of insulin 95% of GLUT4 is located in the cell, but on insulin binding, GLUT4 is translocated to the surface and is able to transport glucose inside.

This current study  published in Food & Function showed that gallate-type catechins reduce insulin-induced glucose uptake by reducing the translocation of GLUT4 to the outside of the cell.  In contrast, the team discovered that in the absence of insulin, when GLUT4 is usually contained intracellularly, a different group of catechins, nongallate-type, increased glucose uptake by increasing the translocation of GLUT4 to the outside of the cell.  An analysis of the signalling pathways involved showed that the gallate-type catechins inhibited the insulin-signalling pathway, but that the nongallate-type catechins were able to increase translocation of GLUT4 without utilising this pathway.

The team from Kobe University and the Central Research Institute have demonstrated that green tea catechins modulate glucose transport in adipose tissue, affecting blood glucose levels.  In a world where the incidence of hypoglycaemia is increasing year by year, insights such as these are invaluable in identifying possible compounds which have the potential to regulate blood glucose levels.

Anna Simpson

Read more about this article:

Manabu Ueda, Takashi Furuyashiki, Kayo Yamada, Yukiko Aoki, Iwao Sakane, Itsuko Fukuda, Ken-ichi Yoshida and Hitoshi Ashida
Food Funct., 2010, DOI: 10.1039/C0FO00105H, Paper
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Broccoli’s cancer protection is activated by bacteria in the lower gut

Bacteria in the lower gut are responsible for breaking down of the major cancer fighting chemical in broccoli to release its bioactive form, claim Elizabeth Jeffery and colleagues at the University of Illinois.

Cruciferous vegetables such as broccoli have been shown to reduce cancer risks. Of all the components present in crucifers such as antioxidants and flavonoids, it is believed that a molecule called glucoraphanin (GRP) plays a major role explaining their anticancer properties.  GRP is actually a precursor to the bioactive isothocyanate sulforaphane (SF).  It is hydrolysed to SF by an endogenous enzyme in broccoli called myrosinase.  Upon chewing, the myrosinase gains access to the GRP and catalyses hydrolysis within the gastrointestinal tract, however, in cooked broccoli myrosinase is inactivated yet low levels of SF metabolites appear in urine following ingestion, suggesting hydrolysis has, somehow, occurred.

Glucoraphanin hydrolysis by microbiota in the rat cecum results in sulforaphane absorption

Evidence exists that gut bacteria are responsible for GRP hydrolysis but this study is the first to report direct evidence of hydrolysis of a GRP to SF in the lower gut. Jeffery and colleagues investigated, in rats, the hydrolysis by gut bacteria and absorption across the cecum (lower intestine) of GRP from broccoli.  Simulated digestion in vitro confirmed that GRP is not destroyed by digestive enzymes therefore reaches the cecum intact.  Introduction of GRP directly to the cecum resulted in the appearance of SF and SF metabolites in the blood travelling away from the abdomen after 2 hours; in contrast, direct introduction of SF resulted in detection of SF and SF metabolites after only 15 minutes. 

These results show for the first time that SF can be absorbed by the cecum, they also indicate that GRP is broken down to SF in the cecum and then absorbed into the bloodstream.  Finally, an ex vivo study showed that GRP was hydrolysed by the rat’s gut bacteria, however, the hydrolysis product was not SF; reasons for the difference in GRP breakdown in and ex vivo are discussed.

Interested in knowing more? Read the full article here:

Glucoraphanin hydrolysis by microbiota in the rat cecum results in sulforaphane absorption
Ren-Hau Lai, Michael Miller and Elizabeth Jeffery
Food Funct., 2010, DOI:10.1039/C0FO00110D

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Should superfoods be consumed in moderation?

Ronald L. Prior and co-workers in the USA calim that inclusion of cranberry in the diet is effective in modulating some aspects of the metabolic parameters associated with metabolic syndrome.  However, a high dose of cranberries does not neccessarily result in a metabolic response.

Metabolic syndrome refers to the clustering of cardiometabolic risk factors, although it was believed initially to be associated with increased risk of cardiovascular disease; metabolic syndrome has a stronger association with type 2 diabetes.  A characteristic of type 2 diabetes and metabolic syndrome is insulin resistance, a condition where insulin becomes less effective at reducing glucose levels in the body.  Effects of dietary consumption of cranberry powder on metabolic parameters in growing rats fed high fructose diets

Recently, cinnamon has been shown to reduce plasma glucose levels in diabetic patients and a class of phenolic phytochemicals called A-type procyanidins are responsible for this.  A-type procyanidins are only found in a limited number of foods and other than cinnamon, cranberry has the highest concentration.

The team from the U.S. Department of Agriculture and the University of Arkansas set out to determine if phytochemicals in cranberry were effective in normalising selected metabolic parameters associated with metabolic syndrome in high fructose (HF) fed rats.  Rats were fed on low, medium or high levels of cranberry powder (CP).  Fasting plasma glucose and triglycerides were higher in HF fed rats than control rats and were reduced by feeding CP; similarly, oral glucose tolerance test responses were improved and similar to control animals when fed low or medium levels of CP.  Insulin resistance and β-cell function were reduced by CP with medium levels being most effective, furthermore, kidney weight was higher in the HF fed group but feeding with CP decreased kidney weight to normal levels.  More importantly, Prior et al. highlights the importance of dose-response studies and that more is not always better.

Interested in knowing more? Read the full article here:

Effects of dietary consumption of cranberry powder on metabolic parameters in growing rats fed high fructose diets
Ramesh C. Khanal, Theodore J. Rogers, Samuel E. Wilkes, Luke R. Howard and Ronald L. Prior
Food & Funct., 2010, Advance Article
DOI: 10.1039/C0FO00089B , Paper

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Inaugural Food & Function issue now online

Issue 1 of Food & Function is now published online  and access is free upon registration.

In their editorial, Editor-in-Chief Gary Williamson and Managing Editor Sarah Ruthven explain the timeliness of this new journal and the mission of Food & Function to bridge the gap between chemistry and physics of food with health and nutrition.

To whet your appetite here is a small selection of the exceptional content:

I hope that you will agree that this first issue represents an excellent start for the journal and Food & Function is on the right track to become one of the leading journals in the food and nutritional sciences.

Make sure you keep up-to-date with the latest issue by signing up for the Food & Function e-alert and newsletter. 

And we hope this first issue encourages you to submit your work to Food & Function.  

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Interview: We are what we eat

Gary Williamson, Editor in Chief of Food & Function, talks to Kathleen Too about low dose long term nutrition studies, EU regulators and challenges faced by scientists in food industry and academia.

Gary Williamson Gary Williamson is Professor of Functional Food at the University of Leeds, UK where his research interests lie in nutritional and food biochemistry. Before joining the university in 2007, he was head of the nutrient bioavailability group at the Nestle Research Center in Lausanne, Switzerland. He is also editor-in-chief for Food & Function, a new journal from RSC Publishing.
 

How did you become interested in food science research?

After completing my PhD and postdoc in biochemistry, I went to work for the Institute of Food Research in Norwich and gradually became more and more interested in plants and secondary metabolites and their biological activity. Eventually, this led to more studies on functional foods and their biochemical aspects. I have to say also, that I really enjoy good food. So food research has always been one of my main personal interests.

Your research focuses on functional foods and nutraceuticals, can you explain what these terms mean?

Functional foods are foods that have an activity above and beyond basic nutrition. Nutraceuticals tend to cover food extracts and supplements with a biological activity or with a proposed biological activity.

You’ve worked in both industry and academia, what are the different challenges facing scientists in these areas?

In industry, one problem is that there is a perceived bias in your research. If a company is doing a study on a particular product, then it is seen by the outside world that the company will do all it can for this product to succeed. But, actually, when I was at Nestlé, I can safely say that a lot more evidence was required to prove the benefit of a particular food to convince the managers to believe in the product. So in industry, the scientists are a lot more critical in the initial stages of a discovery and the perceived bias from the outside world is often not correct. In industry, you have less freedom to do research but more resources are available compared to academia. Sometimes, in industry, the scientists themselves can have different goals to the company goals. In academia, the biggest challenge is the money. Always money!

What kind of research do you think food industry should be funding?

Generally, the food industry has a preference for short term studies. But these may not give them the results that they like. It would be really good if industry could fund longer term studies, lasting years rather than weeks, in human nutrition. It is important to do long term low dose studies which are more difficult to conduct and to obtain measurable effects. Most scientists do pharmaceutical-type studies which are acute and high dose studies. The main challenge is to find new techniques that would allow us to do these long term low dose studies. People eat and drink all the time, so how do we study the effects of what they have been eating or drinking all their life? This is the main challenge.

How long does it take from the conception of an idea to its commercialisation?

What are the main barriers to overcome? It always takes too long to commercialise a product especially from the point of view of non-scientists in industry, such as managers and marketing people. It can take anywhere between 2 and 20 years. The main issue is not how long it takes but the different expectations of the different people on the project. That’s why marketing people have to understand that science is slow and painstaking and the scientists have to understand that marketing people cannot wait as long as they want them to wait. The other barrier is the regulators who are becoming stricter all the time. They are trying to apply the rules from the pharmaceutical industry to that of nutrition and I think that it is never going to work like that. Regulatory hurdles are becoming greater and if they are not careful, they may well strangle the science.

Why did you leave industry?

I left industry because I was keener to work on my own research and not necessarily on a specific product. I wanted to be in a university environment with PhD students and surrounded by the general ‘university expertise’. Also I reached the level I could in industry without going into more managerial roles and away from research, which I did not want to do.

What are your tips to become a successful scientist?

The bottom line is look after the people that work for you and motivate them to be at their best. The success of every project is a team effort. If you do not invest time in the people you work with, then they do not get the best out of the work and they do not get to discuss their ideas with you. My approach is to try to get them to do the best job they can and to do a first class thesis. This would benefit them for the rest of their life and also me in advancing my research.

As the editor-in-chief for the new RSC journal Food & Function, could you comment on the aims of this journal?

There is a real need for a new journal focussing on the novel aspects of food and nutrition and not just the conventional nutrition research that has been around for decades but covers some of the newer ideas of how food affects the health and how we can modify its structure to improve its health aspects.

If you weren’t a scientist, what would you do?

I am a keen photographer so maybe I would have my own photography company. Alternatively, I would like to think that I could have been a good barrister.

Also of interest

Food & Function: A new peer-reviewed journal linking the chemistry and physics of food with health and nutrition. Simply register to access all the Food & Function articles for free.

Chemistry for a healthy diet: Interview with Cesar Fraga, Associate Editor of Food & Function

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How do onions help our heart?

Hypocholesterolemic activity of onion is mediated by enhancing excretion of fecal sterols in hamstersThey may make us cry but onions are actually good for us, and researchers in China are beginning to explain why…

Lei Guan, Hau Yin Chung*, Yalun Su,
Rui Jiao, Cheng Peng and Zhen Yu Chen*
Food & Funct., 2010, Advance Article
DOI: 10.1039/C0FO00036A, Paper

 Levels of plasma total cholesterol (TC) correlate directly with the risk of coronary heart disease, one of the biggest killers worldwide.  Previous studies have shown that onion favourably modifies TC levels, but the underlying mechanism is not understood. 

Hau Yin Chung, Zhen Yu Chen and co-workers studied the effect of dietary onion powder with the protein expression of key receptors and enzymes involved in cholesterol metabolism.  Results demonstrated that onion decreased plasma TC in a dose-dependent manner, accompanied by enhanced excretion of fecal sterols.

Expression analysis demonstrated an upregulation in the expression of liver X receptor-alpha (LXRα), a protein which activates the production of cholesterol-7α-hydroxylase (CYP7A1).  CYP7A1 is a rate-limiting enzyme in the conversion of cholesterol to bile acids and is responsible for the elimination of excessive cholesterol in the liver.  This study shows that it is the upregulation of CYP7A1 which is most likely to explain the decreased plasma TC and enhanced fecal sterol excretion.

Interested in knowing more?  Read the full article here.

Simply register to access all the Food & Function articles for free.

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First Food & Function articles are published

The first Food & Function articles are now online. I hope you enjoy reading these first articles and more will follow very shortly, with the first issue of the Journal being published in October.

Some of the first papers published include:

Anti-inflammatory activity of natural dietary flavonoids by Min-Hsiung Pan, Ching-Shu Lai and Chi-Tang Ho

Comparison of the polyphenolic composition and antioxidant activity of European commercial fruit juices by Alan Crozier, Gina Borges and William Mullen

Hypocholesterolemic Activity of Onion Is Mediated by Enhancing Excretion of Fecal Sterols in Hamsters by Zhen-Yu Chen, Lei Guan, Hau Yin Chung, Yalun Su, Rui Jiao and Cheng Peng

Read all of the Food & Function articles online.

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Keep up to date with news from Food & Function

Food for Thought is the quarterly newsletter that will keep you up to date with all of the latest news from Food & Function.

 

Sign up for Food for Thought today!

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