Novel illudalane sesquiterpenes from <i>Encephalartos villosus</i> Lehm. antimicrobial activity

<p>Phytochemical investigation of <i>Encephalartos villosus</i> Lehm. leaves afford two new illudalane sesquiterpenes namely Encephaldiene 1 and Encephaldiene 2 together with four known flavone glycosides, Luteolin-7-rutinoside, Luteolin-7-glucoside, Luteolin-7-rhamnoside and Apigenin-7-glucoside<i>.</i> The structures of the isolated compounds were elucidated by means of spectroscopic methods including 1D and 2D NMR experiments along with HRESIMS spectrometry. Antimicrobial activity of CHCl₃ and MeOH extracts was investigated. Both extracts showed antibacterial activity against Gram-positive bacteria <i>Streptococcus pneumonia</i> and <i>Bacillus subtilis</i>, and antifungal activity against <i>Aspergillus fumigatus</i>. While CHCl₃ extract showed additional activity against Gram-negative bacteria <i>Escherichia coli</i>.</p

Diuretic activity of ethanolic extract of <i>Panicum repens</i> L. roots and rhizomes

<p>The diuretic activity of ethanolic extract of <i>Panicum repens</i> was investigated in rats. A single oral dose of 500 mg/kg of <i>P. repens</i> extract were given to rats, after 24 h, urine volume, its sodium and potassium concentrations were estimated. Treatment with <i>P. repens</i> extract caused a significant increase in tested parameters as compared to their corresponding controls, <i>p</i> < 0.05.</p

A Chemical–Biological Study Reveals C₉‑type Iridoids as Novel Heat Shock Protein 90 (Hsp90) Inhibitors

The potential of heat shock protein 90 (Hsp90) as a therapeutic target for numerous diseases has made the identification and optimization of novel Hsp90 inhibitors an emerging therapeutic strategy. A surface plasmon resonance (SPR) approach was adopted to screen some iridoids for their Hsp90 α binding capability. Twenty-four iridoid derivatives, including 13 new natural compounds, were isolated from the leaves of <i>Tabebuia argentea</i> and petioles of <i>Catalpa bignonioides</i>. Their structures were elucidated by NMR, electrospray ionization mass spectrometry, and chemical methods. By means of a panel of chemical and biological approaches, four iridoids were demonstrated to bind Hsp90 α. In particular, the dimeric iridoid argenteoside A was shown to efficiently inhibit the chaperone in biochemical and cellular assays. Our results disclose C₉-type iridoids as a novel class of Hsp90 inhibitors