title: Synergistic antioxidative effect of astaxanthin and tocotrienol by co-encapsulated in liposomes.
abstract: Astaxanthin and vitamin E are both effective antioxidants that are frequently used in cosmetics, as food additives, and in to prevent oxidative damage. A combination of astaxanthin and vitamin E would be expected to show an additive anntioxidative effect. In this study, liposomes co-encapsulating astaxanthin and the vitamin E derivatives α-tocopherol (α-T) or tocotrienols (T3) were prepared, and the antioxidative activity of these liposomes toward singlet oxygen and hydroxyl radical was evaluatedin vitro. Liposomes co-encapsulating astaxanthin and α-T showed no additive anntioxidative effect, while the actual scavenging activity of liposomes co-encapsulating astaxanthin and T3 was higher than the calculated additive activity. To clarify why this synergistic effect occurs, the most stable structure of astaxanthin in the presence of α-T or α-T3 was calculated. Only α-T3 was predicted to form hydrogen bonding with astaxanthin, and the astaxanthin polyene chain would partially interact with the α-T3 triene chain, which could explain why there was a synergistic effect between astaxanthin and T3 but not α-T. In conclusion, co-encapsulation of astaxanthin and T3 induces synergistic scavenging activity by intermolecular interactions between the two antioxidants.
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Kamezaki
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Ami
authors.initials: A
authors.lastname: Nakashima
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Yamada
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Uenishi
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishibashi
authors.affiliation: Department of Pharmaceutical Health Chemistry, Institute of Biomedical Sciences, Tokushima University, Graduate School, 1 Shomachi, Tokushima 770-8505, Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Shibuya
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Hama
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Shinzo
authors.initials: S
authors.lastname: Hosoi
authors.affiliation: AstaReal Co., Ltd., The Front Tower Shiba Koen 12th Floor, 2-6-3 Shiba Koen, Minato-ku, Tokyo 105-0011, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Yamashita
authors.affiliation: Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan; Department of Pharmaceutical Health Chemistry, Institute of Biomedical Sciences, Tokushima University, Graduate School, 1 Shomachi, Tokushima 770-8505, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kogure
keywords: astaxanthin; intermolecular interaction; synergistic activity; tocotrienol; vitamin E