Biological Activities of Low-Molecular Weight Compounds Found in Foods and Plants
HIDEKI SHIRATSUCHI11, SHAINA CHANG2, ALFREDA WEI3, AHMED H. EL-GHORAB3 AND TAKAYUKI SHIBAMOTO2*
1. Department of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, Japan
2. Department of Environmental Toxicology, University of California, Davis, U.S.A.
3. Department of Molecular Biosciences, University of California, Davis, U.S.A.
4. National Research Center, Flavor and Aroma Department, Dokki, Cairo, Egypt
ABSTRACT
Among 27 essential oils tested, 11 oils exhibited strong antioxidant activity (95 - 100%) with dose response, which was comparable to that of α-tocopherol. The essential oils showing such activity were ylang-ylang, rose, parsley seed, jasmine, celery seed, basil, anise star, clove leaf, bergamot, thyme, and cinnamon leaf. Among antioxidant components found in these essential oils, eugenol, benzaldehyde, and thymol exhibited comparable activity to that of known natural antioxidant α-tocopherol. Benzyl alcohol, maltol, γ-butyrolactone, and terpinene-4-ol had moderate antioxidant activity. Low-molecular weight heterocyclic compounds, which are the chemicals responsible for cooked flavor, comprise one fourth of the over 400 volatile compounds identified in cooked foods. Among heterocyclic compounds found in the Maillard reaction products (MRP), furans and pyrroles exhibited relatively potent antioxidative activities. Moreover, these heterocyclic compounds showed significant synergic effects. Although the activity of each low-molecular weight compound is not as strong as the known antioxidant, α-tocopherol or BHT, the total activity of numerous compounds might be comparable to those of known antioxidants because tremendous numbers of these chemicals are present either in essential oils or in MRP. Therefore, constant and consistent consumption of foods and beverages containing these low molecular weight antioxidants may prevent diseases caused by oxidative damage.
Key words: Low-molecular weight compounds, essential oils, antioxidants, Maillard reaction products, heterocyclic compounds