3 research outputs found
Isolation of Arginase Inhibitors from the Bioactivity-Guided Fractionation of <i>Byrsonima coccolobifolia</i> Leaves and Stems
<i>Byrsonima coccolobifolia</i> leaf and stem extracts
were studied in the search for possible leishmanicidal compounds using
arginase (ARG) from <i>Leishmania amazonensis</i> as a molecular
target. Flavonoids <b>1b</b>, <b>1e</b>–<b>1g</b>, <b>2a</b>, <b>2b</b>, and <b>2d</b>–<b>2f</b> showed significant inhibitory activity, with IC<sub>50</sub> values ranging from 0.9 to 4.8 μM. The kinetics of the most
active compounds were determined. Flavonoids <b>1e</b>, <b>1f</b>, <b>2a</b>, <b>2b</b>, and <b>2e</b> were
characterized as noncompetitive inhibitors of ARG with dissociation
constants (<i>K</i><sub>i</sub>) ranging from 0.24 to 3.8
μM, demonstrating strong affinity. Structure–activity
relationship studies revealed some similarities in the structural
features of flavonoids related to ARG activity
Biological and Chemical Control of <i>Sclerotinia sclerotiorum</i> using <i>Stachybotrys levispora</i> and Its Secondary Metabolite Griseofulvin
<i>Sclerotinia sclerotiorum</i> is responsible for the
white mold of soybeans, and the difficulty to control the disease
in Brazil is causing million-dollar damages. <i>Stachybotrys
levispora</i> has shown activity against <i>S. sclerotiorum</i>. In our present investigation, we analyzed the chemical basis of
this inhibition. Eight compounds were isolated, and using spectroscopic
methods, we identified their structures as the known substances 7-dechlorogriseofulvin,
7-dechlorodehydrogriseofulvin, griseofulvin, dehydrogriseofulvin,
3,13-dihydroxy-5,9,11-trimethoxy-1-methylbenzophenone, griseophenone
A, 13-hydroxy-3,5,9,11-tetramethoxy-1-methylbenzophenone, and 12-chloro-13-hydroxy-3,5,9,11-tetramethoxy-1-methylbenzophenone.
Griseofulvin inhibited the mycelial growth of <i>S. sclerotiorum</i> at 2 μg mL<sup>–1</sup>. Thus, the antagonistic effect
of <i>S. levispora</i> to <i>S. sclerotiorum</i> may well be due to the presence of griseofulvins. Our results stimulate
new work on the biosynthesis of griseofulvins, to locate genes that
encode key enzymes in these routes and use them to increase the production
of these compounds and thus potentiate the fungicide effect of this
fungus. <i>S. levispora</i> represents an agent for biocontrol,
and griseofulvin represents a fungicide to <i>S. sclerotiorum</i>