Bioassay-guided isolation of antibacterial constituents from <i>Diospyros lotus</i> roots

<div><p>The aim of this study was to explore the extract/fractions and compounds of <i>Diospyros lotus</i> against various Gram-positive and Gram-negative bacteria strain. The results showed marked susceptibility of extract and its fractions against test pathogens. Among them, chloroform fraction was most dominant and effective against all tested bacteria. The chloroform fraction was subjected to column chromatography which led to the isolation of lupeol (<b>1</b>), 7-methyljuglone (<b>2</b>), β-sitosterol (<b>3</b>), stigmasterol (<b>4</b>), betulinic acid (<b>5</b>), diospyrin (<b>6</b>) and 8-hydroxyisodiospyrin (<b>7</b>). Among the isolated compounds, betulinic acid (<b>5</b>) showed significant activity against most of the tested pathogen. In conclusion, our study validated the traditional uses of the plant in the treatment of infectious diseases which was also strongly supported by the isolated compound, betulinic acid (<b>5</b>).</p></div

Anti-hyperalgesic activity of crude extract and 7-methyljuglone of <i>Diospyros lotus</i> roots

<div><p>This study was designed to evaluate the antihyperalgesic effect of crude extract of <i>Diospyros lotus</i> followed by the isolation and characterisation of 7-methyljuglone in acetic acid and formalin tests. The pretreatment of crude extract evoked dose-dependent inhibition of noxious stimulation with maximum effect of 56.78% in acetic acid-induced writhing test, which were 51.89% and 60.69% in first and second phases, respectively, at 100 mg/kg i.p. The structure of 7-methyljuglone was confirmed by spectroscopic analysis. 7-Methyljuglone evoked profound increase in pain threshhold dose dependently; when it was studied in acetic acid-induced writhing test with 63.73% pain attenuation while 51.22% and 65.44% pain amelioration in first and second phases, respectively, at 100 mg/kg i.p. In conclusion, crude extract and 7-methyljuglone of <i>D. lotus</i> roots possessed both peripheral and central antinociceptive potential and thus could be a useful new therapeutic agent.</p></div

Pistagremic acid, a novel β-secretase enzyme (BACE1) inhibitor from <i>Pistacia integerrima</i> Stewart

<div><p>A new triterpenic compound named pistagremic acid (PA) was once again isolated from <i>Pistacia</i><i>integerrima</i>. The β-secretase inhibition study was carried out. Compound PA was found significantly active against β-secretase enzyme (BACE1) with IC₅₀ value of 350 ± 2 nM in comparison to the standard inhibitors [Asn670, Sta671, Val672]-amyloid-β/A4 precursor protein 770 fragment 662–675 (IC₅₀ = 290.71 ± 1 nM). The selectivity of this compound was also evaluated against the acetylcholinesterase and butyrylcholinesterase enzymes. Interestingly compound PA was found to be inactive against them and showed selectivity towards β-secretase enzyme (BACE1).</p></div