| Summary: | 碩士 === 高雄醫學大學 === 天然藥物研究所 === 98 === Neolitsea daibuensis Kamikoti (Lauraceae) is a small semideciduous trees, endemic to Taiwan, confined to broad-leaved forests from 800 to 1,000 m in the southern part. Only one alkaloid, S-(+)-reticuline, was previously isolated from the root wood and root bark of this plant. The biological activity of this species has
never been conducted before.
Recently, approximately 40 species of Formosan Lauraceous plants have been screened for anti-inflammatory activity using an inducible nitric oxide synthase (iNOS) assay, and the methanolic extract of the root of this species has been shown with potent inhibition of NO production without any cytotoxicity on RAW 264.7 cells. Besides, the chemical constituents of its root have not extensively been studied yet.
Bioassay-guided fractionation of the ethyl acetate soluble layer of the root of this species led to the isolation of three new alkaloids: daibucarbolines A-C (1-3), three new sesquiterpenoids: daibulactones A-B (4-5), and daibuoxide (6), along with twenty known compounds: linderalactone (37), pseudoneolinderane (41), linderadine (44), epicubebol methyl ether (7), eudesm-4(15)-ene-1β, 6α-diol (8), hiiranlactone C (9), (+)-8a-hydroxyelemol (10), isolinderalactone (66), sericealactone (67),two flavonoids, 7-O-methylnaringenin (11) and prunetin (12), one steroid, β-sitosterol (181), and eight alkanoids, methyl linoleate (13), 2,3-dihydroxypropyl palmitate (14), methyl palmitate (15), methyl stearate (16), stearic acid (17), docosanoic acid (18), oleic acid (19) and α-tocopherylquinone (20). The structures of these compounds were determined by spectroscopic analysis.
Among the isolates, daibucarboline A (1), hiiranlactone C (9),7-O-methylnaringenin (11), prunetin (12) and isolinderalactone (66) showed iNOS inhibitory activity with IC50 values as 18.41 ± 0.47, 29.30 ± 0.92, 19.55 ± 0.89, 10.50 ± 0.33 and 0.30 ± 0.01 μM, respectively.
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