The chemistry and physiological functions of sesame

Abstract

Some historical facts on and botanical descriptions of sesame are given. Some flavor studies of raw and roasted sesame seeds and oils are described. Composition and some usages are also briefly reported. Sesame has long been regarded in the Orient as a health food which increases energy and prevents aging. Sesame oil has been known empirically as a cooking oil which is highly resistant to oxidative deterioration in comparison with other edible oils. Until recently there were no scientific studies to elucidate these interesting aspects of sesame seed and oil, but the author and members of his group initiated studies on the chemical elucidation of antioxidative principles of sesame seed and oil, and extensively investigated the antiaging effect of sesame. Presence of various new antioxidative lignan phenol compounds in sesame seed and oil is described. Sesaminol has been identified as a new antioxidative principle in raw sesame salad oil. The mechanism of the superior antioxidative activity of roasted sesame oil is being elucidated and is consistent with the synergistic effect of the browning products with tocopherol, sesamol, and sesamin. Noticeable results concerning the antiaging effect of sesame have been shown in a series of animal experiments. The suppressive effect on senescence in mice by long‐term feeding of sesame was demonstrated. Sesame lignans had a synergistic effect on vitamin E activities when added to tocopherols. The addition of sesame lignans, especially that of antioxidative lignan sesaminol in the diets of rats, markedly enhanced vitamin E activity of γ‐tocopherol to the same level of α‐tocopherol, and also significantly enhanced the vitamin E activity of α‐tocopherol. These effects were accompanied by a marked increase in the concentrations of these tocopherols in blood and liver. The enhancement of vitamin E activity by lignans is very important from the viewpoint of evaluating vitamin E activity as well as the antiaging effect of various foods. Various interesting physiological activities of sesame lignans in animal and human tests were shown, such as hypocholesterolemic activity, suppressive activity of chemically induced cancer, and enhancing effect on various liver activities involving detoxification of carbon tetrachloride and ethanol. These recent developments in chemical and physiological studies on sesame seed and oil seem to partially unveil the mystery surrounding sesame though there remain many interesting physiological activities in various aspects of advanced nutritional and phsyiological sciences which need to be clarified. These recent studies demonstrate that sesame, though a minor constituent of daily diets, plays an important role in developing the potential powers of other food constituents as well as markedly raising food quality, not just in the aroma and taste, but also in nutritional and physiological aspects. Because much attention has been focused on the effect of the daily diet on health, especially on circulatory disorders, carcinogenesis, and senility, it seems that sesame seed and oil should be considered as one of the more valuable foods for good health and for good quality of life in general.