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Two new diterpenoids, 14,18-dihydroxyabieta-8,11,13-trien-7-one (1) and 13-acetyl-14,18-dihydroxy-podocarpa-8,11,13-triene (2), together with eight known compounds, i.e., gaultheric acid (3), vanillic acid (4), 4-hydroxybenzoic acid (5), cinnamic acid (6), stearic acid (7), palmitic acid (8), beta-sitosterol (9), and stigmasterol (10), were isolated from the MeOH extract of the whole plant of Gaultheria itoana Hayata (Ericaceae). The structures of the new constituents were elucidated by spectroscopic methods (UV, IR, and 1D- and 2D-NMR) and by mass spectrometry (HR-ESI-MS). Among them, 1 and 2 were demonstrated to exhibit significant cytotoxic activity against the LNCaP cell line.

Fractionation of an ethanol-soluble extract of the seeds of Swietenia macrophylla yielded six new limonoids, swielimonoids A-F (1-6), along with 20 known compounds. Compounds 1 and 2, mexicanolide-type limonoids, were assigned with an α,β-unsaturated δ-lactone moiety (ring D) and a C═C bond between C-8 and C-30. Compounds 3-6 could be categorized as highly oxygenated phragmalin-type limonoids. The structures of these new compounds were elucidated through the interpretation of spectroscopic data. The antidengue virus 2 activities of the isolated components from S. macrophylla were investigated, and of 12 compounds subjected to bioassay, compounds 2 and 7-10 were found to show inhibitory activity in the range 3.5 to 12.5 μM. Among these, the new limonoid 2 exhibited significant antiviral activity (EC50 = 7.2 ± 1.33 μM) with a selectivity index (CC50/EC50) value of >27.7.

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