New chalcanonol glycoside from the seeds of saw palmetto: antiproliferative and antioxidant effects

<div><p>A new chalcanonol glycoside dimer, <i>bis</i>-<i>O</i>-[(I-4′) → (II-6′)]-α-hydroxyphloretin-2′-<i>O</i>-β-glucoside (<b>1</b>), in addition to six known compounds, namely ( − )-epicatechin (<b>2</b>) and ( − )-epiafzelechin (<b>3</b>), 4-hydroxybenzoic acid (<b>4</b>), protocatechuic acid (<b>5</b>), methylgallate (<b>6</b>), β-sitosterol (<b>7</b>) and β-sitosterol-3-<i>O</i>-glucoside (<b>8</b>), was isolated from the seeds of saw palmetto. The structures of the isolated compounds were established from the analysis of their MS and 1D and 2D NMR spectroscopic data. The antiproliferative activities of the isolated compounds towards PC3, the human prostate cancer cells were investigated. Amongst the isolated compounds, the new compound and the sterolic derivatives showed antiproliferative effects. Screening of the antioxidant effects of the isolated compounds by 2,2′-azino-<i>bis</i>-(3-ethylbenzthiazoline-6-sulfonic acid radical assay revealed that the isolated phenolics were active free radical scavengers.</p></div

Antimicrobial and antiquorum-sensing activity of <i>Ricinus communis</i> extracts and ricinine derivatives

<p>Ricinine (<b>1</b>), a known major alkaloid in <i>Ricinus communis</i> plant, was used as a starting compound for the synthesis of six ricinine derivatives; two new and four known compounds. The new derivatives; 3-amino-5-methyl-1<i>H</i>-pyrazolo[4,3-c]pyridin-4(5<i>H</i>)-one (<b>2</b>), and 3-amino-5-methyl-1-(phenylsulfonyl)-1<i>H</i>-pyrazolo[4,3-c]pyridin-4(5<i>H</i>)-one (<b>3</b>), as well as the previously prepared derivatives (<b>4</b>–<b>7</b>) were subjected for antimicrobial and antiquorum-sensing evaluation in comparison to different <i>R. communis</i> extracts. Acetyl ricininic acid derivative (<b>5)</b> showed the highest antimicrobial activity among all tested derivatives against <i>Staphylococcus aureus</i>, <i>Escherichia coli</i>, <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeuroginosa</i> and <i>Candida albicans</i>. However, compound <b>7</b> (4-methoxy-1-methyl-2-oxo-1,2-dihydropyridine-3-carboxamide) showed the highest antiquorum-sensing activity among all tested compounds and extracts. These findings proved the usefulness of ricinine as a good scaffold for the synthesis of new antimicrobial and antiquorum-sensing derivatives in spite of its poor contribution to the antimicrobial activity of the plant extracts.</p

Derivatization, molecular docking and <i>in vitro</i> acetylcholinesterase inhibitory activity of glycyrrhizin as a selective anti-Alzheimer agent

<p>Acetylcholinesterase inhibitors (AChE-Is) increase both level and duration of action of acetylcholine (ACh); thus, alleviate symptoms of Alzheimer’s disease (AD). Glycyrrhizin, is the main active compound in liquorice root. Its aglycone, glycyrrhetinic acid, has shown several beneficial pharmacological activities. This study reports the synthesis and screening of a series of glycyrrhetinic acid analogs as AChE-Is. Fourteen derivatives were prepared, of which five derivatives are recorded as new viz., 3-phenyl-carbamoyl-18β-glycyrrhetinic acid (<b>J9</b>), 3-acetyl-18β-glycyrrhetinic-30-anilinamide (<b>J10</b>), 3-acetyl-18β-glycyrrhetinic-30-ethanolamide (<b>J11</b>), 3-acetyl-18β-glycyrrhetinic-30-<i>n</i>-butylamide (<b>J12</b>) and 18β-glycyrrhetinic acid-30-prenyl ester (<b>J14</b>), in addition to nine known derivatives (<b>J1</b>-<b>J8</b> & <b>J13</b>). Compounds <b>J12, J11, J0</b> and <b>J3</b> showed remarkable AChE-I activity with IC₅₀ values of 3.43, 5.39, 6.27 and 8.68 μM, respectively. These results are in full agreement with the docking study. The active compounds were non-cytotoxic to normal cells (WI-38).</p

Derivatization, molecular docking and <i>in vitro</i> acetylcholinesterase inhibitory activity of glycyrrhizin as a selective anti-Alzheimer agent

<p>Acetylcholinesterase inhibitors (AChE-Is) increase both level and duration of action of acetylcholine (ACh); thus, alleviate symptoms of Alzheimer’s disease (AD). Glycyrrhizin, is the main active compound in liquorice root. Its aglycone, glycyrrhetinic acid, has shown several beneficial pharmacological activities. This study reports the synthesis and screening of a series of glycyrrhetinic acid analogs as AChE-Is. Fourteen derivatives were prepared, of which five derivatives are recorded as new viz., 3-phenyl-carbamoyl-18β-glycyrrhetinic acid (<b>J9</b>), 3-acetyl-18β-glycyrrhetinic-30-anilinamide (<b>J10</b>), 3-acetyl-18β-glycyrrhetinic-30-ethanolamide (<b>J11</b>), 3-acetyl-18β-glycyrrhetinic-30-<i>n</i>-butylamide (<b>J12</b>) and 18β-glycyrrhetinic acid-30-prenyl ester (<b>J14</b>), in addition to nine known derivatives (<b>J1</b>-<b>J8</b> & <b>J13</b>). Compounds <b>J12, J11, J0</b> and <b>J3</b> showed remarkable AChE-I activity with IC₅₀ values of 3.43, 5.39, 6.27 and 8.68 μM, respectively. These results are in full agreement with the docking study. The active compounds were non-cytotoxic to normal cells (WI-38).</p