Abstract:
In recent years, research on the chemistry of entophytic fungi has
become an important source of secondary metabolites. As a continuation of our
investigation on chemistry and bioactivity of entophytic fungi from seaweeds, fungal
strain Aspergillus terreus isolated from red alga, Laurencia ceylanica was cultivated in
bulk and extracted with EtOAc. Above extract was subjected to various
chromatographic techniques to give a new compound (1) along with 9 known
compounds butyrolactone-l(2), (+)-terrein (3), (+>territonin (4), (+)-territonin-A (5),
(+)-asterrelenin (6), 6-hydroxymellin(7), (3R,4R)-6,7-dimethoxy-4-hydroxymellin (8),
oleic acid and gucopyranosyl-p-sitosterol. I3C NMR and DEPT spectra of I showed 20
carbon signals including one carbonyl, one methoxy, and ten quaternary carbons. Its IH
NMR spectrum showed signals due to seven aromatic protons, two methylene protons,
one aldehyde proton and one methoxy group. The positive CIMS of 1 showed its
molecular ion peak at m/z 385.0 corresponding to [M + H],+ and the molecular formula
of I was deduced as C20HI6O8. Comparison of the spectral data of 1 with a known
compound (2) which was isolated from the same extract, and 2D NMR experimental
data indicated 1 to be 3-hydroxy-4-(4-hydroxyphenyl)-5-methoxycarbonyl-5-(4-
hydroxy-3-formylbenzyl)-2,5-dihydro-2-furanone.
Urease is known to be a major cause of pathologies induced by Helicobacter
pylori (HP) which allows HP to survive at low pH of the stomach during colonization
and therefore plays an important role in the pathogenesis of gastric and peptic ulcer,
which may lead to cancer. Hence, compounds from Aspergillus terreus extract were
subjected to urease inhibitory activity assay. Of them, compound 3 showed a significant
urease inhibition activity with an IC50 value of 116.8 uM, compare to positive control
Thiourea (IC50 = 21 uM). As 3 has shown, significant activity, further investigations
are in progress.
