A new minor homoisoflavonoid from <i>Caesalpinia sappan</i>

<div><p>Homoisoflavonoid is a special type of flavonoid with the perspectives of both chemical diversity and significant biological activities. During our ongoing studies on the discovery of novel homoisoflavonoids from traditional Chinese medicines, a new minor 3,4-di-<i>O</i>-substituted homoisoflavonoid, 3′,4-di-<i>O</i>-methylepisappanol (<b>1</b>), was isolated from <i>Caesalpinia sappan</i>, and its structure was determined to be (3<i>R</i>,4<i>R</i>)-3,7-dihydroxy-3-(3′-methoxy-4′-hydroxybenzyl)-4-methoxychroman by various spectroscopic analyses. Meanwhile, a known xanthone derivate, 2-methoxy-3-hydroxyxanthone (<b>2</b>) was also isolated, which is the first example from the genus <i>Caesalpinia</i>.</p></div

A pair of taxifolin-3-<i>O</i>-arabinofuranoside isomers from <i>Juglans regia</i> L.

<p>Diaphragma juglandis Fructus has been known for its effect on tonifying kidney in traditional Uighur medicine. During our ongoing studies on the discovery of biologically active compounds from folk medicine, a pair of flavanonol glycoside isomers named (2<i>S</i>,3<i>S</i>)-taxifolin-3-<i>O</i>-α-d-arabinofuranoside (<b>1</b>) and (2<i>S</i>,3<i>S</i>)-taxifolin-3-<i>O</i>-α-l-arabinofuranoside (<b>2</b>) were isolated, among them, <b>1</b> was a new compound. It is the first report of taxifolin-3-<i>O</i>-arabinofuranosides in both α-d and α-l configuration forms in genus <i>Juglans</i>. Their structures were determined on the basis of spectroscopic analysis and chemical evidence, in combination with circular dichroism.</p

Photocatalytic Oxidation of Aqueous Ammonia Using Atomic Single Layer Graphitic‑C₃N₄

Direct utilization of solar energy for photocatalytic removal of ammonia from water is a topic of strong interest. However, most of the photocatalysts with effective performance are solely metal-based semiconductors. Here, we report for the first time that a new type of atomic single layer graphitic-C₃N₄ (SL g-C₃N₄), a metal-free photocatalyst, has an excellent photocatalytic activity for total ammonia nitrogen (TAN) removal from water. The results demonstrated that over 80% of TAN (initial concentration 1.50 mg·L^–1) could be removed in 6 h under Xe lamp irradiation (195 mW·cm^–2). Furthermore, the SL g-C₃N₄ exhibited a higher photocatalytic activity in alkaline solution than that in neutral or acidic solutions. The investigation suggested that both photogenerated holes and hydroxyl radicals were involved the TAN photocatalytic oxidation process and that the major oxidation product was NO₃^–-N. In addition, SL g-C₃N₄ exhibited good photocatalytic stability in aqueous solution. This work highlights the appealing application of an inexpensive metal-free photocatalyst in aqueous ammonia treatment

Isolation, Structural Elucidation, and Liquid Chromatography–Mass Spectrometry Analysis of Steroidal Glycosides from Polygonatum odoratum

The rhizomes of Polygonatum odoratum represent a traditional Chinese medicine and functional food. A phytochemical investigation resulted in the isolation of eight steroidal glycosides (<b>1</b>–<b>8</b>), including two new compounds, polygonatumosides F (<b>1</b>) and G (<b>2</b>). The structures were elucidated by spectroscopic data and chemical reactions. Compound <b>7</b> showed antiproliferation activity against human hepatocellular carcinoma cell line HepG2 (IC₅₀ of 3.2 μM). The chemical profile and contents of steroidal glycosides of P. odoratum rhizomes collected at different dates and geographical locations were also investigated, indicating that the rational harvest of P. odoratum in spring and autumn is preferable to obtain higher levels of steroidal glycosides. Compounds <b>1</b> and <b>7</b> showed the highest contents in all P. odoratum samples and have potential to serve as chemotaxonomic and chemical markers for quality control of this important plant material. 14-Hydroxylation may be a key step for the biosynthesis of compounds <b>1</b>–<b>7</b>