Secondary Metabolites from the Root of Neolitsea daibuensis and Their Anti-inflammatory Activity
Neolitsea daibuensis Kamikoti (Lauraceae) is a small semideciduous trees, endemic to Taiwan, confined to broad-leaved forests from 800 to 1000m in the southern part.
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), together with twenty known compounds. The structures of these compounds were determined by spectroscopic analysis.
Among the isolates, daibucarboline A (1), hiiranlactone B, isolinderalactone, 7-O-methylnaringenin, and prunetin showed iNOS inhibitory activity with IC50 values as 18.41±0.47, 29.30±0.92, 0.30±0.01, 19.55±0.89, and 10.50±0.33µM, respectively.
Acknowledgement: National Science Council of the Republic of China (NSC 99–2300-B-037–009)