Stilbene

The direct E/Z configuration assignment of tri- and tetra-substituted stilbenes (and other analogous olefins) when only one of the isomers is available is a quite challenging task. Sometimes, a chemical transformation or some other tedious method is necessary for determination of the double bond substitution pattern. In this paper, we relied on theoretical calculation of chemical shifts as a complementary tool for 1H NMR determination of the configuration of an α-phenylcinnamic acid prepared as a unique isomer by the Perkin reaction.

Due to the spreading and increasing drug resistance of pathogens, the search for novel antibiotics is becoming ever more
important. Plant-derived polyphenols are a vast and promising class of compounds with a potential to fight infectious diseases.
Still, they are not routinely used in clinical practice. No reports on the in vivo studies of these compounds have been presented.
The aim of our work was to compare the antimicrobial activity of resveratrol (stilbene), dihydroquercetin and dihydromyricetin
(flavonols) extracted from the bark and wood of conifers against the dermatophytes Staphylococcus aureus, Pseudomonas
aeruginosa  and  Candida  albicans.  Using  the  radial  diffusion  assay,  we  established  that  dihydroquercetin,  resveratrol  and
dihydromyricetin exhibit high activity against S. aureus even at the smallest possible concentrations of 0.22, 0.15, and 0.15 mM,
respectively. In contrast, the highest achievable concentrations of these compounds in the solutions (21.5, 15.5 and 15.0 mM
for  dihydroquercetin,  resveratrol  and  dihydromyricetin,  respectively)  have  no  effect  on  the  growth  of  P.  aeruginosa  and
C. albicans. These findings suggest that polyphenols derived from conifers could have a potential to be used as a medicine for
topical application to treat bacterial infections of the skin caused by S. aureus.
Keywords: polyphenols, flavonoid, stilbene, antimicrobial agents, resveratrol, antimicrobial activity, antioxidants, wood

Resveratrol is among the best-known secondary plant metabolites because of its antioxidant, anti-inflammatory, and anticancer properties. It also is an important allelopathic chemical widely credited with the protection of plants from pathogens. The ecological role of resveratrol in natural habitats is difficult to establish rigorously, because it does not seem to accumulate outside plant tissue. It is likely that bacterial degradation plays a key role in determining the persistence, and thus the ecological role, of resveratrol in soil. Here, we report the isolation of an Acinetobacter species that can use resveratrol as a sole carbon source from the rhizosphere of peanut plants. Both molecular and biochemical techniques indicate that the pathway starts with the conversion of resveratrol to 3,5-dihydroxybenzaldehyde and 4-hydroxybenzaldehyde. The aldehydes are oxidized to substituted benzoates that subsequently enter central metabolism. The gene that encodes the enzyme responsible f...

The direct E/Z configuration assignment of tri- and tetra-substituted stilbenes (and other analogous olefins) when only one of the isomers is available is a quite challenging task. Sometimes, a chemical transformation or some other tedious method is necessary for determination of the double bond substitution pattern. In this paper, we relied on theoretical calculation of chemical shifts as a complementary tool for 1H NMR determination of the configuration of an α-phenylcinnamic acid prepared as a unique isomer by the Perkin reaction.

This work deals with the preparation of stilbene-based resveratrol analogs by employing the Perkin reaction, aiming at synthesizing potential antitumor lead compounds and evaluating their pharmacological activities. The proliferation inhibitor test against tumor cell lines identified analogs 9 and 11 as the most active among all synthesized derivatives, presenting IC50 in micromolar range for certain cell lines. For study on the embryonic development, compounds 8 and 9 at the lowest tested concentration (41.7 μM) that inhibited sea urchin egg development, but only after third cleavage were used. Both the compounds inhibited 100% of normal development since first cleavage. These data partially corroborated the results obtained with MTT assay using tumor cell lines. None of the tested compounds revealed hemolytic action in assay with mouse erythrocytes. By employing Perkin reaction, seven stilbene-based resveratrol analogs have been prepared in order to examine their in vitro activity against tumor cell lines and embryonic development of sea urchin egg.

This work deals with the preparation of stilbene-based resveratrol analogs by employing the Perkin reaction, aiming at synthesizing potential antitumor lead compounds and evaluating their pharmacological activities. The proliferation inhibitor test against tumor cell lines identified analogs 9 and 11 as the most active among all synthesized derivatives, presenting IC50 in micromolar range for certain cell lines. For study on the embryonic development, compounds 8 and 9 at the lowest tested concentration (41.7 μM) that inhibited sea urchin egg development, but only after third cleavage were used. Both the compounds inhibited 100% of normal development since first cleavage. These data partially corroborated the results obtained with MTT assay using tumor cell lines. None of the tested compounds revealed hemolytic action in assay with mouse erythrocytes.