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 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