Journal of Experimental Food Chemistry

The possibility of finding anti-cancer drugs has generated interest in natural products. Several studies have in vitro observed potent anti-cancer properties of pomegranate juice against various cancers including leukaemia. Although a few studies have described the bioactivities of hydrolysable tannins extracted from pomegranate juices, limited attention has been paid to other tannins extracted from different parts of a plant. Recently, polyphenols, which are found in plants, have become the most studied phytochemicals owing to their significant chemical properties and biological activities. Tannin is an astringent plant polyphenolic compound and has been observed to have anti-oxidant and anti-cancer properties. This study uses a novel approach to study variation in the structure of hydrolysable tannins from two different types of plants and their inhibition activity in leukaemia K562 cells. We examined data showing anti-proliferation activity of hydrolysable tannins extracted from pomegranate peels within two concentrations of 1 mg/mL and 100 μg/mL. Hydrolysable tannin extracted from oak apple gall induces different effects than that extracted from pomegranate tannin. At the highest concentration of 100 μg/mL, the tannin from oak apple gall did not have any noticeable effects on cells, whereas at the highest concentration of 1 mg/mL, cell cycle arrest seemed to have occurred after 72 h of treatment. This most likely led to senescence caused by overstimulation of the cells by specific polyphenols compounds in oak apple gall, which affected the cells either directly or indirectly by changing the culture’s environment.

Objective: The objective of this study is to study the effect of temperature, lipoxygenase activity, substrate and fruit type on formation of volatiles in the LOX pathway. Methods: Volatiles in the headspace of tomato, bell pepper, tomatillo, strawberry, apple and pear were measured during and after fruit tissue disruption in real time using selected ion flow tube mass spectrometry (SIFT-MS) at 4, 25, 37 and 45°C for 60 min, and were compared to lipoxygenase (LOX) activity and fatty acid concentration. Results: In tomatoes, bell peppers and tomatillos, (Z)a-3-hexenal, (E)-2-hexenal and hexanal increased rapidly after blending, peaked and declined, while in strawberry, apple and pear they sometimes peaked and sometimes remained constant over the 60 min. In tomato and bell pepper, the peak levels of (Z)-3-hexenal, (E)-2-hexenal and hexanal in the LOX pathway had good correlations to LOX activity, which was greatest at 25°C. In contrast, tomatillo, strawberry, apple and pear had lower LOX activity, their 6C aldehydes did not show strong correlation with LOX activity, and the volatiles increased with increasing temperature to 45°C. The concentrations of hexen-1-ol and 1- hexanol did not correlate to LOX activity for any of the fruits. In tomato, bell pepper and tomatillo, there was no significant correlation between the ratio of linoleic acid:linolenic and the ratio of hexanal:hexenal. In strawberry, apple and pear, there were good correlations between linolenic acid content and concentrations of (E)-2-hexenal, hexenal and hexen-1-ol. Conclusion: Thus the effect of enzyme activity and substrate composition on formation of volatiles in the lipoxygenase pathway remains complicated and difficult to predict.

The traditional Mediterranean diet refers to a dietary pattern found in olive growing areas of the Mediterranean region. It’s essential characteristic is the consumption of virgin olive oil, vegetables, fresh fruits, grains, pasta, bread, olives, pulses, nuts and seeds. Moderate amounts of fish, poultry, dairy products and eggs are consumed with small amounts of red meat and wine. Over the past few decades there has been a growing interest in the role of the Mediterranean diet in preventing the development of certain diseases, especially cardiovascular disease. Mediterranean food products are now re-evaluated for the beneficial health effects in relation to the presence of bioactive compounds. The body of science unraveling the role of bioactives such as phenolic acids, various polyphenols, flavonoids, lignans, hydroxyl-isochromans, olive oil secoiridoids, triterpene acids and triterpene alcohols, squalene, αlpha-tocopherol and many others is growing rapidly. A challenge for future research is the magnitude of the contribution of each active compound to the overall positive health effect. Strategies to preserve and disseminate the healthy Mediterranean diet should focus on: the implementation of the claim recently approved by EFSA for the level of biophenols in olive oil and the protection of LDL oxidation; technological improvements based on the increased awareness about the role of minor constituents of Mediterranean foods; products that are innovative but also traditional.