Recent Advances in Phytochemicals

Corrie Cox

DTC 608

June 13, 2010

Introduction

In the past twenty years, phytochemicals and their importance in various foods have been

recognized and established (1). More recently, phytochemicals have been the focus of many research

studies, and are now seen on the market as dietary supplements. Each phytochemical found in food

sources plays a different role in the human body. Carotenoids are known to reduce the risk of cancer and

flavonoid molecules are potent antioxidants. Furthermore, anthocyanin compounds, which are found in

berries, help to improve neuronal and cognitive brain functions. In addition, they help with ocular health

and protect DNA integrity. Phytochemicals such as phenolic acids and tannins naturally occur in coffee

and tea, and research has proven they may help in the prevention of chronic and degenerative disorders

(2). The following studies discuss current literature that is published (or in press) in regards to

advancements in phytochemicals. In addition, Table 1 (found on pg. 6) lists phytochemicals, food sources,

and their benefits. Also, see Figure 1 (found on pg. 7) for photomicrgraphed images of two common

phytochemicals.

The factors that influence phytochemical content include: the weather (year-to-year),

environmental conditions from one farm to the next, soil conditions, and farming methods. These

factors affect the nutritional content of crops, which can influence the amount of phytochemicals that

will be in a crop (1).

Sablani and colleagues (3) reviewed the effects of thermal treatments on phytochemicals in

conventionally and organically grown raspberries and blueberries. They measured anthocyanins,

phenolic compounds, and antioxidant activity. The berries were either steam blanched or non-blanched

than placed into cans with sugar syrup. Then both blanched and non-blanched red raspberries and

blueberries were stored in sterilized bottles in the form of processed fruit juice and pureed berries.

Throughout each process any changes in phytochemicals were closely monitored. Prior to blanching,

the berries showed no significant changes in anthocyanin and phenolic contents. The study showed

that during canning, anthocyanin decreased and phenolic content and antioxidant activities increased.

Moreover, blanching improved the amount of phytochemicals held in blueberries prior to the

puree/juicing process. The agricultural production system used (i.e organic or conventional) for both

red raspberries and blueberries showed no significant influence on total anthocyanin, phenolic

compounds, and antioxidant activity during each process.

Milbury and colleagues (4) conducted a study of anthocyanins in blueberries because numerous

studies have suggested that phytochemicals found in berries play a role in reversing age related

cognitive impairment. Additionally, they have been know to protect against neurodegenerative

disorders. For an eight week duration, pigs were fed 2% whole freeze-dried, powered blueberry.

Levels of anthocyanins were measured in the brain. Xenobiotic metabolism had taken place and

anthocyanins were removed by the blood which cause a loss of the phytochemicals. The study

concluded that the benefits of the phytochemicals found in berries were beneficial to the body through

gene expression and signal transduction in the human brain, not through direct phytochemical mega-

doses.

Ferruzzi (2) conducted a literature review on the two most commonly consumed beverages in

the world, coffee and tea. Epidemiological data suggests these beverages have provided evidence that

supports its role in preventing chronic and degenerative diseases. Coffee and tea are both rich sources

of bioactive phytochemicals such as: methylxanthines, amino acids, phenolic acids, and polyphenols.

Recent attention is being drawn to the polyphenols and phenolic acids which are abundant in both

coffee and tea. Their reported biological activities that have been shown include antioxidant activities,

stimulation of NO production and vasolidation, regulation of xenobiotic-metabolizing enzymes,

increased fatty acid oxidation and insulin sensitivity, and modulation of glucose absorption and

utilization.

Hayes and colleagues (5) evaluated the effects of selected phytochemicals on quality indices

and sensorial properties of raw and cooked pork stored in different packaging systems. They injected

raw and cooked pork with lutein, sesamol, ellagic acid and olive leaf extract and stored the pork patties

aerobically or in modified atmosphere packs for up to twelve days. The results showed that in both

packaging systems, sesamol, ellagic acid, and olive leaf extract exhibited significant lipid antioxidant

activity in raw and cooked pork. In addition, the study suggests these phytochemicals can be added to

raw and cooked pork and may prove to be safe, natural, and functional ingredients for the pork industry

to utilize in the development of novel functional pork products.

Pellegrini and colleagues (6) studied the phytochemical content and total antioxidant content of

fresh or frozen broccoli, Brussel sprouts, and cauliflower during boiling, microwaving, and basket and

oven steaming. The results showed that fresh broccoli, Brussel sprouts, and cauliflower were able to

retain phytochemicals and total antioxidant content better than the frozen broccoli, Brussel sprouts, and

cauliflower during each cooking method. Steaming preserved the phytochemicals in the fresh

vegetables better than microwaving and the basket and oven steaming method in both the fresh and

frozen vegetables.

Hervert-Hernandez and colleagues (7) conducted studies on the bioactive compounds in hot

peppers. The peppers contain an abundance of phytochemicals that contain antioxidant properties. The

study measured the individual antioxidant, carotenoid, and phenolic content of four hot peppers. In

addition, using an in vitro gastrointestinal model, the degree of intestinal bioaccessibility of carotenoids

(with significance in human health), beta-carotene, beta-cryptoxanthin, and zeaxanthin were estimated.

At ripe stage, all four hot peppers had a high content of bioactive compounds that exhibited significant

antioxidant properties, such as polyphenols and carotenoids, which were partly bioaccessible. The

results suggest 50 to 80% of these carotenoids could reach the colon to be potentially fermented or

could remain unavailable.

Agriculture Research on Phytochemicals

Research is also conducted to see if growers can increase the phytochemical content of lettuce

grown in a greenhouse. Li and colleagues (8) studied the effects of exogenous abscisic acid (ABA) on

yield, antioxidant capacities, and phytochemical content of red and green loose leaf lettuce. On the 30th

and 39th days after sowing, three concentrations of ABA in water were sprayed on the blocks, on the

46th day the lettuce was harvested. The phenolic compounds in the red and green lettuce included

caffeoyltartaric acid, 5-O-caffeoylquinic acid, dicaffeoyltartaric acid, 3,5-dicaffeoylquinic acid, and

quercetin 3-(6''-malonyl)-glucoside. In addition, cyanidin 3-glucoside, cyanidin 3-(3''-malonoyl)-

glucoside, and cyanidin 3-(6''-malonoyl)-glucoside were seen in the red lettuce. Significant increases

of individual phytochemical content in red lettuce were measured in response to the ABA except for 5-

O-caffeoylquinic acid; whereas no significant change was observed in the green lettuce. Significant

increases in antioxidant content were observed in both types of lettuce.

Xu and colleagues (9) measured the nutritional and functional properties of immature corn

grains, which are being used as a popular snack/vegetable. In the study, plants at multiple stages were

examined to see if any changes occurred in nutrients, phytochemicals, and antioxidant activity in corn

grains during different stages of growth. The results of the study revealed that during the growth

period of corn grains, phytochemicals and antioxidant levels both decreased.

Current research conducted by Zhang and colleagues (10) studied the phenolic profiles and

antioxidant activity of black rice bran of differenct commercially available varieties. The objective of

the study was to determine the phytochemical profiles and antioxidant activities from twelve varites of

black rice in comparison to white rice. The results of the comparison showed the average values of

free, bound, and total antioxidant activty of black rice was significantlly higher than that of white rice

bran. In addition, all tweleve varities of black rice had higher content of total phenolics, total

flavonoids, and total anthocyans (specifically cyanidin-3-glucoside, cyanidin-3-rutinoside, and

peonidin-3-glucoside) when compared to white rice. The study suggest that knowing the

phytochemical profile and antioxidant activity of black rice bran gives insights to its potential

application to promote health.

Conclusion

In conclusion, the phytochemical content of foods is dependent on many variables including

crop conditions, packaging systems used, cooking methods, etc. Phytochemicals are not essential

nutrients; however when consumed, they can help in the prevention of chronic and degenerative

diseases. The future of phytochemicals is in educating consumers on actual health benefits.

Additionally, further research needs to be conducted specifically in regards to actual health benefits, not

just assumed benefits.

Table 1. Phytochemicals, food sources, and benefits ( from reference 11).

Phytochemical Name Food Source Benefits

Allicin Garlic or onions May lower serum cholesterol and and protect against cardiovascular disease.

Capsaicin Hot peppers May reduce blood clotting.

Carotenoids Carrots, sweet potatoes, spinach, kale, etc.

May have anti-cancer benefits.

Flavinoids Blueberries, black raspberries, and cranberries

May help to improve memory.

Indoles Cruciferous vegetables Appear to block carcinogens from damaging DNA.

Isothiocyanates Cruciferous vegetables Inhibit enzymes that promote cancer activity.

Lignans Whole grains and some seeds (flax seeds)

May help prevent cancers that are estrogen positive from spreading or metastasizing.

Limonene Citrus fruits May inhibit cancer growth.

Lycopene Tomatoes, pink grapefuit, watermelon, guava, and papaya

May retard the growth of cancers, particularly prostate cancer.

Phenolic Acids Coffee and fruits May promote excretion of carcinogens.

Phytic Acid Whole grain May inhibit free radical activity.

Phytosterols Soybeans May slow rate of some cancers.

Resveratrol Grapes, peanuts, and red wine. Inhibits cell growth and lowers risk of blood clotting.

Saponions Legumes and vegetables May slow DNA replication which affects growth rate of cancer cells.

Tannins Tea, wine, and legumes Can inhibit cancer activity.

Vitamin C Vegetables and fruit May help lower the risk of oral, throat, larynx, and esophageal cancer.

Figure 1. Photomicrographs of common phytochemicals ( from reference 12).

Capsaicin

Phenethyl Isothiocyanate ( A Phenolic Acid)

References:

1. Crinnion W. Organic foods contain higher levels of certain nutrients, lower levels of pesticides, and

may provide health benefits for the consumer. Altern Med Rev. 2010;15(1):4-12.

2. Ferruzzi M. The influence of beverage composition on delivery of phenolic compounds from coffee

and tea. Physiol Behav. 2010;100(1):33-41.

3. Sablani S., Andrews P., Davies N., Walters T., Saez H., Syamaladevi R., Mohekar P. Effect of

thermal treatments on phytochemicals in conventionally and organically grown berries. J Sci Food

Agric. 2010;90(5):769-78.

4. Milbury P., Kalt W. Xenobiotic metabolism and berry flavonoid transport across the blood-brain

barrier. J Agric Food Chem. 2010;58(7):3950-6.

5. Hayes J., Stepanyan V., O'Grady M., Allen P., Kerry J. Evaluation of the effects of selected

phytochemicals on quality indices and sensorial properties of raw and cooked pork stored in different

packaging systems. Meat Sci. 2010;85(2):289-96.

6. Pellegrini N., Chiavaro E., Gardana C., Mazzeo T., Contino D., Gallo M., Riso P., Fogliano V.,

Porrini M. Effect of different cooking methods on color, phytochemical concentration, and antioxidant

capacity of raw and frozen brassica vegetables. J Agric Food Chem. 2010;58(7):4310-21.

7. Hervert-Hernandez D., Sayago-Ayerdi S., Goni I. Bioactive compounds of four hot pepper varieties

(Capsicum annuum L.), antioxidant capacity, and intestinal bioaccessibility. J Agric Food Chem.

2010;58(6):3399-406

8. Li Z., Zhao X., Sandhu A., Gu L. Effects of Exogenous Abscisic Acid on Yield, Antioxidant

Capacities, and Phytochemical Contents of Greenhouse Grown Lettuces. J Agric Food Chem. 2010; In

press.

9. Xu J., Hu Q., Wang X., Luo J., Liu Y., Tian C. Changes in the main nutrients, phytochemicals, and

antioxidant activity in yellow corn grain during maturation. J Agric Food Chem. 2010;58(9):5751-6.

10. Zhang M., Zhang R., Zhang F., Liu R. Phenolic Profiles and Antioxidant Activity of Black Rice

Bran of Different Commercially Available Varieties. J Agric Food Chem. 2010; In press.

11. Phytochemicals and Functional Foods. The Bellevue College Website.

http://scidiv.bellevuecollege.edu/rkr/Biology130/lectures/pdfs/Phytochemicals130.pdf . Published April

1999 and October 2003. Accessed June 6, 2010.

12. Davidson M. The Phytochemical Collection. The Florida State University Website.

http://micro.magnet.fsu.edu/micro/gallery/phytochemicals/phytochemical.html . Published September

19, 1995. Updated March 8, 2004. Accessed Jun 6, 2010.