Plants naturally produce compounds called phytochemicals that protect their immune systems from disease, bacteria and fungi. The term "phytochemical" refers to a large group of compounds but within this group are several specific types that further break down into sub-groups. Polyphenols and saponins are types of phytochemicals identified as containing disease-preventing properties in human nutrition. However, research is ongoing to determine the exact effect these chemicals have on your health.
Protective Activity of Polyphenols
The most abundant source of dietary antioxidants can be found in polyphenol-containing foods. Antioxidants are important substances that protect your cells from damaging free radical molecules. Your body naturally produces antioxidants and eating healthy foods containing antioxidants increases your chance of maintaining a healthy immune system. Factors like aging, infections or disease can harm normal cell survival. The protective activity of polyphenols may improve cell survival and protect against oxidative stress in humans, according to a 2005 review published in the "American Journal of Clinical Nutrition."
Main Polyphenol Classes
Polyphenols are classified based on the phenol rings they contain but more than 8,000 polyphenolic compounds exist, according to a 2009 review published in "Oxidative Medicine and Cellular Longevity." Flavonoids, lignans and stilbenes are the main polyphenols identified as having protective properties. Flavonoids are responsible for the color, taste and aroma of plants and are divided further into subclasses including anthocyanins, isoflavones and flavonols. Lignans have phytoestrogens, or natural estrogen activity, and these may protect against cancers related to hormonal changes in aging. Stilbenes have antifungal compounds that protect against infections or injury. Resveratrol is a stilbene studied for its cholesterol-lowering effect, notes MayoClinic.com.
Saponins
Saponins are a sugar constituent, or glucoside, found in plants that have a fat-soluble and water-soluble component, which cause the compound to foam. Inside plants the foaming quality acts as a detergent or cleanser but inside your digestive system, saponins bind with bile salts and cholesterol resulting in a reduction of blood cholesterol. Saponins also have antifungal and antibacterial properties but research is ongoing to determine effectiveness of this action in humans, notes Dr. Peter Cheeke of the Linus Pauling Institute. According to a 2003 study from the University of California, Davis, published in Science Daily, saponin compounds in red wine may be more effective than resveratrol in their action of protecting against heart disease.
Polyphenol and Saponin Food Sources
Resveratrol and saponins are abundant phytochemicals in fermented alcohol products like red wine and beer. If you prefer non-alcoholic beverages, grape juices also has polyphenol and saponin compounds. Additional food products include soy beans, tofu and berry varieties. Apples, cantaloupe, cranberries, broccoli, celery, onion and whole grains also contain a rich source of polyphenol compounds.
References
- American Journal of Clinical Nutrition; Polyphenols; Antioxidants and Beyond; Augustin Scalbert et al; January 2005
- Journal of Medicinal Plants Research; Relationship Between Antioxidant and Antiglycation Ability of Saponins, Polyphenols.....to Treat Diabetes; Yun-Fang Chen et al; June 2011
- Linus Pauling Institute; Saponins; Suprising Benefits of Desert Plants; Peter R. Cheeke, PhD; May 1998
- MayoClinic.com; Red Wine, Antioxidants and Resveratrol; Good For Your Heart?; Mayo Clinic Staff; March 4, 2011
- Oxidative Medicine and Cellular Longevity; Plant Polyphenols as Dietary Antioxidants in Human Health and Disease; Kanti Bhooshan Pandey et al; July 2009
- University of California Davis; Some Facts About Phytochemicals; Karrie Henernan PhD et al; 2009
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