Two new quercetin glycoside derivatives from the fruits of <i>Gardenia jasminoides</i> var. <i>radicans</i>

<div><p>Two new quercetin glycoside derivatives named quercetin-3-<i>O</i>-[2-<i>O</i>-<i>trans</i>-caffeoyl-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (<b>1</b>) and quercetin-3-<i>O</i>-[2-<i>O</i>-<i>trans</i>-caffeoyl-β-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (<b>2</b>) along with three known flavonoids, 5-hydroxy-6,7,3′,4′,5′-pentamethoxyflavone (<b>3</b>), 5,7-dihydroxy-8-methoxyflavone (<b>4</b>) and kaempferol 3-<i>O</i>-β-d-glucopyranoside (<b>5</b>), were isolated from the fruits of <i>Gardenia jasminoides</i> var. <i>radicans</i>. The structures of the new compounds were determined by means of extensive spectroscopic analysis (1D, 2D NMR and HR-ESI-MS), glycoside hydrolysis and sugar HPLC analysis after derivatisation. This is the first report on the isolation of a pair of compounds with α or β-l-rhamnopyranosyl configuration from plant and the first detail assignment of their NMR data.</p></div

Secondary metabolites from marine-derived <i>Streptomyces antibioticus</i> strain H74-21

<p>A new secondary metabolite, (2<i>S</i>,3<i>R</i>)-l-threonine, <i>N</i>-[3-(formylamino)-2-hydroxybenzoyl]-ethyl ester (streptomyceamide C, <b>1</b>), together with four known compounds 1, 4-dimethyl-3-isopropyl-2,5-piperidinedione (<b>2</b>), cyclo-((<i>S</i>)-Pro-8- hydroxy-(<i>R</i>)-Ile (<b>3</b>), cyclo-((<i>S</i>)-Pro-(<i>R</i>)-Leu (<b>4</b>), and seco-((<i>S</i>)-Pro-(<i>R</i>)-Val) (<b>5</b>), were isolated from the EtOH extract of the fermented mycelium of the marine-derived <i>streptomycete</i> strain H74-21, which was isolated from sea sediment in a mangrove site. The structure of the new compound was established on the basis of its spectroscopic data, including 1D and 2D NMR, HR-TOF-MS. Their antifungal activities against <i>Candida albicans</i> and cytotoxicities against human breast adenocarcinoma cell line MCF-7, human glioblastoma cell line SF-268 and human lung cancer cell line NCI-H460 were tested. Compounds <b>1</b> only displayed cytotoxicity against human breast adenocarcinoma cell line MCF-7 with the IC₅₀ value of 27.0 μg/mL. However, compounds <b>1</b>–<b>5</b> do not show antifungal activities at the test concentration of 1 mg/mL, and <b>2</b>–<b>5</b> have no cytotoxicities at the test concentration of 50 μg/mL.</p