Latest research on ingredients that make chocolate, olive oil, tea healthful foods

September 11th, 2013
The scientific spotlight focuses today on the healthful antioxidant substances in red wine, dark chocolate, olive oil, coffee, tea, and other foods and dietary supplements that are enticing millions of consumers with the promise of a healthier, longer life. The American Chemical Society, the world's largest scientific society, is holding a symposium on those substances during its 246th National Meeting & Exposition.

Reports in the symposium involve substances that consumers know best as "antioxidants," and that scientists term "phenolic derivatives." These ingredients, found naturally in certain foods and sold as dietary supplements, have been linked with health benefits that include reducing the risk of heart disease and cancer.

Entitled "Phenolic Derivatives for Food and Human Health," the symposium was held today. The meeting continues through Thursday in the Indiana Convention Center and downtown hotels. Thousands of scientists and others are expected for the meeting, which features almost 7,000 reports on new discoveries in science and other topics.

Among the topics:

  • The healthful effects of curcumin, found naturally in the spice, turmeric
  • Substances in dried ginger that kill cancer cells
  • How large intestine microbes interact with cranberry antioxidants in the diet
  • Using biotechnology to make more effective antioxidants

Abstracts in the symposium appear below.

Abstracts

Antitumor activity of novel curcumin analogs in hepatocarcinoma (HepG2) cells

H.P.Vasantha Rupasinghe1, vrupasinghe@dal.ca, Khushwant S. Bhullar1, Dani Youssef3, Amitabh Jha2. (1) Environmental Sciences, Dalhousie University, Truro, NS B2N 5E3, Canada, (2) Chemistry, Acadia University, Wolfwille, NS B4P 2R6, Canada, (3) Science, Université Sainte Anne, Church Point, NS B0W 1M0, Canada

Curcumin, a natural polyphenol of turmeric, continues to receive considerable attention as potent antioxidant and anti-cancer agent. Numerous analogues of curcumin have been synthesized and screened for their improved biological activities. An assessment of anticancer activities of curcumin and its novel 15 analogues was conducted in vitro. Various biochemical and toxicological techniques were employed to assess the therapeutic action of the synthetic novel curcumin analogs in comparison to curcumin and Sorafenib™ (a clinically approved drug). Inhibition of the cancer cell (HepG2) proliferation assessed by MTS assay showed that compound 2-[(E)-3-(4-hydroxyphenyl)acryloyl]-6-[1-(4-hydroxyphenyl)meth-(E)-ylidene]-cyclohexanone exhibits the trongest anticancer activity compared to curcumin and Sorafenib™ (p<0.05). 2-[(E)-3-(3,4-Dimethoxyphenyl)acryloyl]-6-[1-(3,4-dimethoxyphenyl)meth-(E)-ylidene]cyclohexanone and curcumin showed the highest cytotoxic effects (p<0.05) in HepG2 cell line, analyzed by LDH release assay. All the curcumin analogues induced apoptosis in tumor cells by caspase-3 activation and DNA fragmentation. It was found that Sorafenib™, compounds 2-[(E)-(3-phenylacryloyl)]-5-[1-phenylmeth-(E)-ylidene]cyclopentanone and 2-((E)-3-p-tolylacryloyl)-6-[1-p-tolylmeth-(E)-ylidene]cyclohexanone induced the highest amount of apoptotic caspase-3 enzyme in cancer cells(p<0.05). Apoptosis in all drug candidates was further confirmed by florescence microscopy using annexin V and 7-ADD dyes. Flow cytometry was employed to analyze cell cycle and it was found that curcumin and its derivatives induced cell arrest at G0/G1 phase in cancer cells. Compounds 2-[(E)-3-(4-Chlorophenyl)acryloyl]-5-[1-(4-chlorophenyl)-meth-(E)-ylidene]-cyclopenta-none and 2-[(E)-(3-Phenylacryloyl)]-6-[1-phenylmeth-(E)-ylidene]cyclohexanone were found to have the highest proportion of cells in apoptotic G0/G1 phase. These effects were also accompanied by catalytic inhibition of human topoisomerase II by all analyzed curcumin analogues. In addition, toxicology study was conducted to investigate toxicity of curcumin derivatives using normal human and rat hepatocytes. It was found that all compounds except 2-((E)-3-p-tolylacryloyl)-6-[1-p-tolylmeth-(E)-ylidene]cyclohexanonewere less cytotoxic than Sorafenib™. The compound 2-[(E)-3-(4-Hydroxyphenyl)acryloyl]-6-[1-(4-hydroxyphenyl)meth-(E)-ylidene]-cyclohexanone with enhanced biological activity and non-toxic manifestations emerged as the strongest drug candidate. The novel curcumin analogue 2-[(E)-3-(4-hydroxyphenyl)acryloyl]-6-[1-(4-hydroxyphenyl)meth-(E)-ylidene]-cyclohexanone was further assessed for its molecular pathway involved in antitumor activity using RT-PCR technique.

In vitro fecal fermentation of cranberry A-type proanthocyanidins

Jason W Soares1, jason.w.soares.civ@mail.mil, Steven Arcidiacono1, Paul Capela2, Kenneth Racicot1, C-Y. Oliver Chen3. (1) U.S. Army Natick Soldier Research, Development and Engineering Command, Natick, MA 01760, United States, (2) Human Protection and Performance Division, Defense Science and Technology Organization, Scottsdale, Tasmania 7260, Australia, (3) Jean Mayer USDA Human Nutrition Research Center, Tufts Univeristy, Boston, MA 02111, United States

In vitro fecal fermentation is a useful tool to elucidate the influence of dietary polyphenol interactions with colonic bacteria on gut function and health. Our work centers on enhancing the understanding of in vitro bacterial hydrolysis of cranberry proanthocyanidins (PAC). Batch and continuous fermentations were performed utilizing fecal inocula, obtained from three individuals, in a nutrient-rich anaerobic media supplemented with purified PAC. Protein content and fatty acid production measurements were evaluated to monitor bacterial fermentation. The addition of PAC slightly stimulated growth, relative to PAC deficient samples, and induced variations in the fatty acid profile, primarily in terms of relative concentrations. PAC utilization and metabolite generation were also investigated. As an ancillary benefit, the study assessed the stability of fecal inocula during storage, which is important when considering reproducibility. These results represent the first steps toward our primary goal of understanding PAC metabolite influence on innate immune function and inflammation.

Metabolites of alkylresorcinols as the exposure markers to reflect whole wheat consumption in human

Yingdong Zhu, yzhu1@ncat.edu, Shengmin Sang. North Carolina Agricultural and Technical State University, North Carolina Research Campus, Kannapolis, NC 28081, United States

An impressive body of evidence supports the notion that increasing consumption of whole grains and/or cereal bran is associated with lower risk of chronic diseases, such as cancer, obesity, diabetes, and heart diseases. Many epidemiological studies, however, have failed to generate consistent results on this topic due to a lack of accurate tools to assess dietary intake and internal dosage. In order to better understand the beneficial health effects of whole grains/cereal bran, biomarkers for their exposure and effects are needed. The bran fraction of the whole grain contains important bioactive phytochemicals and is the major source of cereal fiber. The metabolism of these phytochemicals may reflect inter-individual differences. Alkylresorcinols (ARs) are phenolic lipids found in high concentrations exclusively in the outer parts of wheat and rye grains among commonly consumed foods. ARs and its metabolites have been used as the exposure markers to reflect whole wheat/rye consumption. However, the metabolic profile of ARs is still unknown. We recently studied the metabolic profile of ARs in mice and in humans and have identified a unique AR metabolite that can serve as a more accurate exposure marker to reflect whole wheat/rye consumption.

Bioactive phenolic components in ginger for cancer prevention

Shengmin Sang, ssang@ncat.edu, North Carolina Agricultural and Technical State University, North Carolina Research Campus, Kannapolis, NC 28081, United States

Ginger, the rhizome of Zingiber officinale, has been utilized for thousands of years as a spice and crude drug. The major pharmacologically active components of ginger are gingerols and shogaols, which have both been implicated in chemoprevention over the past decade. Shogaols are the products of gingerols after thermal processing and are the primary constituents of dried ginger. Our group demonstrated that [6]-, [8]-, and [10]-shogaols exhibited significantly higher toxicity to HCT-116 human colon and H-1299 human lung cancer cells than [6]-, [8]-, and [10]-gingerols. We have also found that [6]-shogaol was more effective than [6]-gingerol in inhibiting 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced skin tumor promotion in mice. Our studies on the metabolism of [6]-shgaol indicated that it is extensively metabolized in cancer cells, in liver microsomes, and in vivo. Our results also found that most of the metabolites of [6]-shogaol remain bioactive and some of the metabolites even have greater activity than [6]-shogaol in cancer cells and in mice.

Enzymatic synthesis of novel biomolecules of phenolic lipids: A biotechnological approach

Selim Kermasha, selim.kermasha@mcgill.ca, Department of Food Science & Agricultural Chemistry, McGill University, Ste-Anne de Bellevue, Quebec H9X 3V9, Canada

There has been a growing interest in the use of nutraceuticals as food supplements as well as natural bio-ingredients in food industries. Phenolic compounds represent an important group that possesses antioxidant and many functional properties. On the other hand, the numerous health benefits of the ω-3 polyunsaturated fatty acids (PUFAs) have been recognized in the modulation of risk of a variety of diseases and disorders. The incorporation of phenolic compounds into triacylglycerols could potentially result in novel biomolecules, structured phenolic lipids, with enhanced anti-oxidative and functional properties. The synthesized phenolic lipids demonstrated radical scavenging activity, expressed as IC50, 3.7-fold higher than that of dihydroxyphenyl acetic acid, but compared to that of α-tocopherol. In addition, the experimental findings indicated that phenolic lipids exhibited enhanced antioxidant capacity (AOC) by 2.6- to 8-fold higher that of the edible oils. The experimental findings also showed that all synthesized phenolic lipids demonstrated an enhancement in the oxidative stability, when they were exposed to light, oxygen and high temperatures, as compared to that of the edible oils. The presented work will highlight the development of a novel biotechnological approach using enzymes for the production of selected phenolic lipids, using edible oils and endogenous phenolic extracts. The structural, anti-oxidative stability characteristics of these novel biomolecules will be presented.

Phenolics in pressurized fluid systems: From extraction to synthesis

Marleny D. A. Saldaña, marleny@ualberta.ca, Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Alberta T6G 2P5, Canada

Phenolic acids found in various biomass have antioxidant and antimicrobial activities and their consumption have been associated with a lower incidence of cancer, heart disease, and diabetes. Research in my laboratory has focused on the use of pressurized fluids to extract these phenolic compounds to be used in various applications. Pressurized fluids, such as subcritical water and supercritical CO2 (SC-CO2) as "green" and environmentally friendly solvents, can be used for the extraction of phenolic compounds from biomass as well as for enzymatic reactions involving phenolic acids. Phenolic compounds were extracted from biomass using pressurized fluids in stainless steel reactors at different temperatures ranging from 100 to 240˚C, pressures of up to 20 MPa and times of up to 180 min. Extracts obtained after biomass treatment using pressurized fluids were evaluated for their phenolic content and antioxidant activity. Results indicated that the total phenolic content and antioxidant activity of the extract increased with extraction temperature. In addition, a phenolic acid was reacted with triglycerides of flax oil using lipase enzyme in SC-CO2 media in a laboratory-scale supercritical system at different temperatures ranging from 40 to 80˚C, pressures from 4 to 35 MPa and times of up to 53 h. Results have shown that SC-CO2 is a promising green solvent for the enzymatic synthesis of phenolic lipids. In addition, the use of selected phenolic compounds in milk as antioxidants was evaluated at temperatures of 60-120˚C, pressures of 100-600 MPa and times of up to 30 min using high pressure processing assisted by temperature. The use of selected phenolic compounds in milk retained valuable components, such as CLA. Results have shown that phenolic acids can be processed using pressurized fluids for different applications.

Transesterified tyrosol and hydroxytyrosol alkylesters from cuphea oil – antioxidant behavior in liposomes

Kervin O. Evans, Kervin.Evans@ars.usda.gov, Joseph A Laszlo, Steven C Cermak, David L Compton, Roque L Evangelista, Mark A Berhow. United States Department of Agriculture, Peoria, IL 61604, United States

Tyrosol and hydroxytyrosol are the antioxidant molecules abundantly found in olive oil. Transesterification of tyrosol and hydroxytyrosol with cuphea oil results in medium chain alkyl esters with antioxidant properties. Membrane partitioning, antioxidant capacity and membrane location of these novel lipids were measured within phospholipid liposomes. Findings demonstrate that both novel lipids partition well within the membrane, possess similar antioxidant characteristics as their parent molecule and position themselves as typical aliphatic lipids. Our findings demonstrate that these two novel antioxidant lipids may serve as food additives that prevent spoilage through oxidation of fats and oils.

Antioxidant efficacy of feruloyl glycerols in model membranes

David L Compton, david.compton@ars.usda.gov, Kervin O Evans, Joseph A Laszlo. U.S. Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, IL 61604, United States

Ferulic acid and its esters are known to be effective antioxidants. Ethyl ferulate was biocatalytically transesterified with triacylglycerols and long chain alcohols to form a series of lipid-based feruloyl esters: feruloylglycerol, diferuloylglycerol, feruloyldiacylglycerol, diferuloylacylglycerol, and octadecyl ferulate. The feruloylglycerol acted as a rapid antioxidant (50% reduction of DPPH radical < 5 min) in ethanol solutions and diferuloyl glycerol was an intermediate antioxidant (50% reduction of DPPH radical in 5

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