Compounds from <em>Terminalia mantaly</em> L. (Combretaceae) Stem Bark Exhibit Potent Inhibition against some Pathogenic Yeasts and Enzymes of Metabolic Significance<strong></strong>

Tchuenmogne MAT, Ngouana TK, Gohlke S, et al. Compounds from &lt;em&gt;Terminalia mantaly&lt;/em&gt; L. (Combretaceae) Stem Bark Exhibit Potent Inhibition against some Pathogenic Yeasts and Enzymes of Metabolic Significance&lt;strong&gt;&lt;/strong&gt;. Preprints. 2016.The chemical investigation of the anti-yeast methanol extract from the stem bark of Terminalia mantaly led to the isolation of seven compounds: 3-O-methyl-4-O-&amp;alpha;-rhamnopyranoside ellagic acid (1), 3-O-mehylellagic acid (2), arjungenin or 2,3,19,23-tetrahydroxyolean-12-en-28-o&amp;iuml;c acid (3), arjunglucoside or 2,3,19,23-tetrahydroxyolean-12-en-28-o&amp;iuml;c acid glucopyranoside (4), 2&amp;alpha;,3&amp;alpha;,24-trihydroxyolean-11,13(18)-dien-28-o&amp;iuml;c acid (5), stigmasterol (6), stigmasterol 3-O-&amp;beta;-D-glucopyranoside (7). Their structures were established by means of spectroscopic analysis and comparison with published data. Compounds 1-5 were tested in vitro for activity against three pathogenic yeast isolates, Candida albicans, Candida parapsilosis and Candida krusei. The activity of compounds 1, 2 and 4 were comparable to that of the reference compound fluconazole (MIC values below 32 &amp;micro;g/ml) against the three tested yeast isolates. They were also tested for inhibitory properties against four enzymes of metabolic significance: Glucose-6-Phosphate Deshydrogenase (G6PD), human erythrocyte Carbonic anhydrase I and II (hCA I and hCA II), Glutathione S-transferase (GST). Compound 4 showed highly potent inhibitory property against the four tested enzymes with overall IC50 values below 4 &amp;micro;M and inhibitory constant (Ki) &amp;lt;3 &amp;micro;M.</jats:p

Synthesis, Urease Inhibition and Molecular Modelling Studies of Novel Derivatives of the Naturally Occurring β-Amyrenone

Abstract Urease enzyme (UE) has been reported to be a potent virulence factor for Helicobacter pylori (HP) bacteria indicated to be responsible for various gastrointestinal diseases. Therefore, the spread of HP, currently regarded by the World Health Organization as a class 1 carcinogen, could be better controlled by targeting UE. It is in this line that we have synthesized three new derivatives (2–4) of the naturally occurring olean-12-en-3-one (1), which was previously isolated from the figs of Ficus vallis-choudae Delile (Moraceae). Among the synthesized compounds, 3 and 4 contain an indole moiety. Their structures were unambiguously assigned by spectroscopic and spectrometric techniques (1D-NMR, 2D-NMR and MS). The starting material and the synthesized compounds were screened for UE inhibition activity, and showed significant activities with IC50 values ranging from 14.5 to 24.6 μM, with compound (1) being the most potent as compared to the positive control thiourea (IC50 = 21.6 μM). Amongst the synthetic derivatives, compound 4 was the most potent (IC50 = 17.9 μM), while the others showed activities close to that of the control. In addition, molecular docking study of target compounds 2–4 was performed in an attempt to explore their binding mode for the design of more potent UE inhibitors. Graphical Abstrac