Synthesis of Highly Substituted Adamantanones from Bicyclo[3.3.1]nonanes

Trifluoromethanesulfonic acid and other electrophiles promote formation of the adamantanone core from the readily accessible 1,5-dimethyl-3,7-dimethylenebicyclo[3.3.1]nonan-9-one 2. Because adamantyl cation 3 can be trapped by a range of nucleophiles, including aromatic and heteroaromatic rings, alcohol, nitriles, and halides, access to a wide variety of functionality at the newly formed tertiary position is provided

Light-Regulated Release of Entrapped Drugs from Photoresponsive Gold Nanoparticles

Release of a payload in a spatiotemporal fashion has a substantial impact on increasing therapeutic efficacy. In this work, a novel monolayer of gold nanoparticles (AuNPs) featuring light-responsive ligands was investigated as a potential drug carrier whose drug release can be triggered by UV light. Hydrophobic molecules were noncovalently entrapped in the compartments of its monolayers. Once irradiated with UV light, the dinitrobenzyl linker was cleaved, leading to release of the entrapped agent. AuNPs were characterized using UV spectrophotometry, TEM, and a zetasizer. A naturally occurring compound extracted from Goniothalamus elegans Ast was chosen as a hydrophobic model drug. Entrapment and release of dye were monitored using fluorimetry. The percent encapsulation of dye was of 13.53%. Entrapped dye can be released upon UV irradiation and can be regulated by changing irradiation time. Up to 83.95±2.2% entrapped dye can be released after irradiation for 20 minutes. In the absence of UV light, dye release was only 19.75%. For comparison purposes, AuNPs having no dinitrobenzyl groups showed a minimal release of 12.23% and 11.69% with and without UV light, respectively. This demonstrated an alternative strategy to encapsulate drugs using a noncovalent approach followed by their controlled release upon UV irradiation

Antiplasmodial and Cytotoxic Flavans and Diarylpropanes from the Stems of <i>Combretum griffithii</i>

Four new flavans, griffinoids A–D (<b>1</b>–<b>4</b>), and two new diarylpropanes, griffithanes E and F (<b>7</b> and <b>8</b>), together with two known flavans (<b>5</b> and <b>6</b>), four known diarylpropanes, and β-sitosterol, were isolated from the EtOAc extract of the stems of <i>Combretum griffithii</i>. Compounds <b>3</b>, <b>4</b>, <b>5</b>, and <b>9</b> exhibited weak antiplasmodial activity, with IC₅₀ values of 15.74, 13.04, 9.66, and 14.45 μM, respectively. In addition, compounds <b>4</b>, <b>5</b>, and <b>8</b> also exhibited weak cytotoxicity toward one or more cancer cell lines including human epidermoid carcinoma, human breast cancer, and human small cell lung cancer cell lines

Phytochemical investigation and acetylcholinesterase inhibitory activity of bark of <i>Hymenodictyon orixense</i>

<p>The chemical investigation of the methanol extract of <i>Hymenodictyon orixense</i> bark, a Thai medicinal herb, provided five compounds. Their structures were identified on the basis of 1D NMR and MS data, as well as by comparison of the data with published values, as an iridoid glycoside: loganin (<b>1</b>), four coumarins: scopoletin (<b>2</b>), scopolin (<b>3</b>), hymexelsin (<b>4</b>) and scopoletin 7-<i>O</i>-<i>β</i>-D-xylopyranosyl-(1→6)-<i>β</i>-D-glucopyranoside (<b>5</b>). Compounds <b>1–5</b> showed acetylcholinesterase (AChE) inhibitory activity in the range of 13.92–34.18% at a concentration of 100 <i>μ</i>g/mL. In addition, compounds <b>1</b> and <b>5</b> are reported for the first time from this genus.</p