| Summary: | 碩士 === 高雄醫學大學 === 天然藥物研究所碩士班 === 103 === Styrax formosana Matsum. (Styracaceae) is a shrub or small tree, endemic to Taiwan and grows in low to medium altitudes forest about 0-2,000 m throughout Taiwan Island. Approximately over 1,400 species of Formosan plants have been screened for biological activities. The methanolic extract of the root of this plant showed free radical scavenging activities. In the past, only one paper reported the leaves’ extract of this plant showing free radical scavenging activities, and its chemical constituents have not been studied. Therefore, the aim of this study is the isolation of chemical constituents and the evaluation of their biological activities.
Firstly, bioassay-guided fractionation of active n-BuOH layer from the root of this species led to the isolation of 3 new lignanoids, styraxinol (93), styraxinone (94), and (–)-lariciresinol-4''-monomethyl ether (97), along with 27 known compounds including 17 lignans, five triterpenoids, three steroids, one sesquiterpene, and one benzenoid。Among these isolates, erythro-1-(4''-hydroxy-3''-methoxyphenyl)-2-[4''-(3-
hydroxypropyl)-2'',6''-dimethoxyphenoxy]propane-1,3-diol (95), (–)-lariciresinol-4''-monomethyl ether (97), (+)-syringaresinol (104), (–)-medioresinol (106), secoisolariciresinol (113) showed ABTS cation radical scavenging activity, with SC50 values of, and 28.6, 31.4, 15.8, 18.9, and 4.4 μM in 20 minute, respectively. In addition, (+)-matairesinol (56), (–)-lariciresinol-4''-monomethyl ether (97), (+)-syringaresinol (104), (–)-medioresinol (106), secoisolariciresinol (113) showed potent DPPH radical scavenging activity, with SC50 values of 18.5, 8.2, 14.0, 14.0, and 14.2 μM in 30 minute, respectively. (+)-syringaresinol (104), (–)-medioresinol (106), secoisolariciresinol (113) had stronger scavenging activity than positive control in both of ABTS and DPPH assays.
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