Identification and nitric oxide production inhibitory activity of phenolic derivatives from the trunks of <i>Gnetum latifolium</i>

Phytochemical investigation of the trunks from Gnetum latifolium led to the isolation of a novel phenolic glucoside, 2E-2,4-di-(3,4-dihydroxyphenyl)but-2-en-1-yl-O-β-D-glucopyranoside (1), along with five known stilbene derivatives (2–6). Their structures were determined mainly using high-resolution electrospray ionisation mass spectrometry and nuclear magnetic resonance spectroscopic analyses, followed by comparisons of observed spectral data with reported values. The novel compound 1 in G. latifolium was found to be useful as a chemotaxonomic marker. Biological evaluation revealed that compound 6 had remarkable inhibitory effects on nitric oxide production, with a half-maximal inhibitory concentration (IC50) value of 4.85 ± 0.20 µM, which was much higher than that of the positive control dexamethasone (IC50 = 14.20 ± 0.54 µM).</p

Chemical constituents from the leaves of <i>Pinus dalatensis</i> Ferré

<p>A phytochemical study of <i>n</i>-hexane and ethyl acetate extracts of <i>Pinus dalatensis</i> Ferré leaves led to the isolation of 11 compounds, including one caryolane sesquiterpenoid (<b>1</b>), five labdane diterpenoids (<b>2</b>, <b>3</b>, <b>4</b>, <b>5, 6</b>), one serratane triterpenoid (<b>7</b>), one diacylated flavonoid glucoside (<b>8</b>), one stilbenoid (<b>9</b>) and two sterols (<b>10</b>, <b>11</b>). The structural characterisation of the isolated compounds was elucidated by spectroscopic data and comparison with the literature report on the chemical constituents from <i>Pinus dalatensis</i> Ferré. Futhermore, three compounds <b>1</b>, <b>4</b> and <b>6</b> were obtained for the first time from the genus <i>Pinus</i>. Besides, compounds (<b>2</b>, <b>3</b>, <b>5</b>, <b>8</b>, <b>9</b>) were also subjected to cytotoxicity effect on SK-LU-1, MCF-7 and Hep-G2 cell lines, but only compound <b>9</b> expressed activities with IC₅₀ values of 141.22, 127.81 and 166.84 μM, respectively.</p

Chemical constituents of <i>Oldenlandia pinifolia</i> and their antiproliferative activities

<p>This study describes the chemical constituents of <i>Oldenlandia pinifolia</i> (Wall. Ex G. Don) Kuntze (synonym <i>Hedyotis pinifolia</i> Wall. Ex G. Don) and discusses their anti-proliferative activities. Thirteen compounds were isolated from the <i>n</i>-hexane, ethyl acetate and <i>n</i>-butanol extracts of whole plants <i>O</i>. <i>pinifolia</i> by chromatography method. Their structures were elucidated using MS and NMR analysis and compared with reported data. They are three anthraquinones, a carotenoid, two triterpenes, four iridoid glycosides and three flavonoid glycosides. Among them, 2-methyl-1,4,6-trihydroxy-anthraquinone is a new one, and three compounds were found for the first time in this genus. MTT assay resulted that the <i>n</i>-butanol extract and four isolated compounds inhibited the proliferation of chronic myelogenous leukaemia cells. The results from Hoechst 33343 staining and caspase 3-inducing exhibited that those four tested compounds induced apoptosis and activated caspase 3 (<i>p</i> < 0.05). One of them, isorhamnetin-3-<i>O</i>-<i>β</i>-rutinoside showed the most activity with IC₅₀ value of 394.68 ± 25.12 μM.</p

Anti-proliferative diterpenes from <i>Dacrycarpus imbricatus</i>

<p>A new diterpene, cassipouryl hexadecanoate (<b>2</b>), in addition to the cassipourol (<b>1</b>) and four terpenes (<b>3–6</b>) were isolated from the twigs and leaves of <i>Dacrycarpus imbricatus</i> (Blume) de Laub. The structures of the two monocyclic diterpenes (<b>1</b>, <b>2</b>), were elucidated on the basic of 1D and 2D NMR spectroscopic data and compared with the literature. These two monocyclic diterpenes (<b>1</b>, <b>2</b>) were tested for their anti-proliferative activity on acute myeloid leukemia (OCI-AML) cells. The results showed that <b>1</b> had significantly anti-proliferative activity whereas <b>2</b> was weakly active.</p