Separation and structural determination of the chloroform-soluble components obtained from the peels of the persimmon (Diospyros kaki Thunb.) were performed. β-Carotene, lycopene, β-cryptoxanthin monomyristic acid ester, zeaxanthin di-myristic acid ester, the latter two of which were accompanied by a small amount of palmitoleic acid in the fatty acid moiety, and oleanolic acid were identified. Among these components, the mono-fatty acid ester of β-cryptoxanthin and the di-fatty acid ester of zeaxanthin were characterized for the first time.Key words persimmon peel; carotenoid; β-cryptoxanthin mono-fatty acid ester; zeaxanthin di-fatty acid ester; myristic acid; palmitoleic acidThe persimmon Diospyros kaki Thunb. is a fruit that is indigenous to Japan, and China, Korea, and Japan produce most of the fruits used for commercial consumption. Persimmons (Kaki) are also used traditionally for medicinal purposes, because of their preventive action against infection, diabetes, and arteriosclerosis, and because of their diuretic effect.1) The persimmon contains many compounds such as different sugars, starch, organic acids, ascorbic acid, tannins, flavonoids, carotenoids, triterpenoids, and fatty acids.2-7) With regard to its pharmacological activities, many studies have reported pharmacological effects including antioxidant activity and tyrosinase inhibitory activity. 3,[8][9][10] The peels of fresh astringent persimmons are usually removed and dried, which yields sweet dried persimmon peels. The peel was found to contain more polyphenols 11) and carotenoids 12) than the fruit body. The persimmon flesh contained large amounts of carotenoids, which are responsible for the color of the fruits.4,5) Unlike vitamin C and vitamin E, β-carotene and other carotenoids can scavenge singlet oxygen.13) Also, carotenoids are known to exist as free compounds or as fatty acid esters in plants. Because the peels of persimmons are usually discarded, we believe that it might be possible to recover the peels for industrial utilization or for use as a food supplement.Breithaupt and Bamedi 14) suggested, on the basis of HPLC results, the occurrence of carotenoid esters as β-cryptoxanthin ester and zeaxanthin ester in persimmons. Weller and Breithaupt 15) also suggested, on the basis of LC/MS results, the presence of zeaxanthin esters as diesters of dipalmitate and of palmitate and stearate in persimmons. However, they did not isolate these compounds as pure single entities. Differences in the chemical structure of each carotenoid and its ester would lead to different pharmacological effects and physicochemical characteristics. For example, synthetic lutein myristate ester was more stable than free lutein after heat or UV treatment.
16)Sugawara et al. 17) found that Caco-2 cells easily took up more hydrophobic carotenoids than less hydrophobic carotenoids. One can easily envision that different carotenoids with or without ester moieties would have different polar characteristics and that differences in structure would lead to different bioch...
