| Summary: | 碩士 === 高雄醫學大學 === 天然藥物研究所 === 97 === Itea parviflora Hemsl. (Saxifragaceae) is a shrub, endemic to Taiwan, common in forest at low to medium altitudes. The methanolic extract from the root of this plant showed antitubercular activity against Mycobacterium tuberculosis H37Rv in vitro. Past chemical study reported the flavonoids, including orientin, isoorientin, vitexin, and isovitexin detected by HPLC method in Itea virginica, I. parviflora and I. japonica, respectively. But their biological activities have not been conducted. The aim of this study is the isolation of chemical and antitubercular constituents from this plant.
The methanolic extract was partitioned into H2O, n-BuOH and EtOAc-soluble layer, and EtOAc-soluble layer showed antitubercular activity. Investigation of the EtOAc-soluble active layer from the root of this species led to the isolation of one new sesquiterpenoid, namely iteaphyllene (1), one new nor-diterpenoid, namely iteakaurenic acid (2), one benzoquinone, iteanone (5) firstly isolated from nature, together with thirteen known compounds: lupeol (3), 3-acetylbetulinal (4), (±)-pinoresinol (6), (+)-7S,8R-dihydrodehydroconiferyl alcohol (7), (–)-epicatechin (8), scopoletin (9), 7-(3,3-dimethylallyloxy)-6-methoxycoumarin (10), 3,4-dimethoxyphenol (11), syringaldehyde (12), 4-acetonyl-3,5-dimethoxy-p-quinol (13), α-tocopheryl quinone (14) and a mixture of β-sitosterol (15) and stigmasterol (16). The structures of these isolates were elucidated by spectral analysis, and iteakaurenic acid (2) was further confirmed by X-ray analysis.
Among these isolates, iteaphyllene (1), scopoletin (9), 7-(3,3-dimethylallyloxy)-6-methoxycoumarin (10) and 3,4-dimethoxyphenol (11) showed antitubercular activity against Mycobacterium tuberculosis H37Rv in vitro with MIC values of 80.0, 42.1, 35.0, 55.0 μg/mL, respectively.
|
|---|
