Investigating relationship between water production and interfacial activity of γ-oryzanol, ethyl ferulate, and ferulic acid during peroxidation of bulk oil

In this study, lecithin (as a surfactant) was added to promote the inhibitory-mechanism of γ-oryzanol, ethyl-ferulate and ferulic acid (based on the interfacial phenomena) so as to inhibit the oxidation of stripped sunflower oil. Monitoring the amount of water production as a byproduct of oxidation showed that the water content of the lipid system increased remarkably through the oxidation progress. Lecithin enhanced the critical concentration of hydroperoxides in reverse micelles, compared to the basic state (14.8 vs. 9.2 mM), thereby improving the hydrogen-donating mechanism of antioxidants. The size of reverse micelles increased progressively during the oxidation, while two breakpoints were pointed out in the micelles growth, i.e. at the end of the initiation and the propagation phases. Based on the kinetic data, ferulic acid showed the highest antioxidant activity (23.4), compared to ethyl-ferulate (15.5) and γ-oryzanol (13.7). Generally, lecithin enhanced antioxidant activity (~ 65%) by improving the interfacial performance of antioxidants.

Identification of Ethyl Ferulate From Rubus corchorifolius L.F. Leaves and Its Inhibitory Effects on HepG2 Liver Cancer Cells

Objectives Rubus corchorifolius L.f., also known as raspberry, March bubble, milk bubble, etc., belongs to the genus Rubus L. and the family Rosaceae. The tender leaves of Rubus corchorifolius L. f. have been made into herbal tea for drinking and relieving coughs in China since ancient times. In this study, we isolated a bioactive compound from the ethyl acetate extract of Rubus corchorifolius L.f. leaves and investigated its protective effects in HepG2 human liver cancer cell line and the underlying molecular mechanisms. Methods Structural analysis of the isolated compound was performed by spectroscopic methods and the compound was identified as ethyl ferulate. Efficacy and mechanisms of ethyl ferulate on the proliferation of HepG2 human liver cancer cells and LO2 normal human liver cells was determined by cell viability, cell morphology, apoptosis, mitochondrial membrane potential, Ca2 + release, and immunoblotting analyses. Results We found that ethyl ferulate significantly suppressed the cell proliferation of HepG2 cells (IC50 26.4 μM), while it did not cause cytotoxicity on LO2 cells. In addition, flow cytometry analysis demonstrated that ethyl ferulate inhibited HepG2 cell growth via inducing cellular apoptosis. Specifically, ethyl ferulate reduced the electrical potential of the mitochondrial membrane and increased the concentration of calcium ions inside cells. Moreover, these changes were accompanied by increases in the expression of the pro-apoptotic proteins, such as cleaved caspase-3 and Bax. In contrast, cell morphology and growth of LO2 cells remained unaffected. Conclusions In conclusion, our findings demonstrated, for the first time, that ethyl ferulate possesses great potential as an effective and safe antitumor agent for cancer chemoprevention in humans. Funding Sources This study was supported by the University of International Cooperation in Science and Technology Innovation Platform Project of Guangdong (2013gjhz0003). XC was partly supported by a scholarship from South China Agriculture University.

Ethyl ferulate contributes to the inhibition of the inflammatory responses in murine RAW 264.7 macrophage cells and acute lung injury in mice

Background Ethyl ferulate (EF) is a derivative of ferulic acid (FA), which is a monomeric component purified from the traditional medicinal herb Ferula, but its effects have not been clear yet. The purpose of this study was to evaluate whether EF can reduce inflammation levels in macrophages by regulating the Nrf2-HO-1 and NF-кB pathway. Methods The LPS-induced raw 264.7 macrophage cells model was used to determine the anti-inflammatory and anti-oxidative stress effects of EF. The levels of IL-1β, IL-6, TNF-α and PGE2 were analyzed by ELISA. The mRNA and protein of COX-2, iNOS, TNF-α, IL-6, HO-1 and Nrf2 were identified by RT-PCR analysis and western blotting. Intracellular ROS levels were assessed with DCFH oxidation staining. The expressions of NF-кB p-p65 and Nrf2 were analyzed by immunofluorescence assay. The inhibitory effect of Nrf2 inhibitor ML385 (2μM) on mediatation of antioxidant activity by raw 264.7 macrophage cells was evaluated. The effect of EF was confirmed in acute lung injury mice model. Results In our research, EF reduced the expression of iNOS, COX2 and the production of PGE2. EF could inhibit the production of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) in lipopolysaccharide (LPS) stimulated macrophages and decreased expression of IL-6 and TNF-α in LPS stimulated macrophages. Furthermore, EF inhibited NF-кB p65 from transporting to the nucleus, decreased the expression of p-IкBα, significantly decreased the level of intracellular reactive oxygen species (ROS) and activated Nrf2/HO-1 pathways. EF could attenuate the degree of leukocyte infiltration, reduced MPO activity, mRNA levels and secretion of TNF-α and IL-6 in vivo. EF exhibited potent protective effects against LPS-induced acute lung injury in mice. Conclusions Collectively, our data showed that EF relieved LPS-induced inflammatory responses by inhibiting NF-κB pathway and activating Nrf2/HO-1 pathway, known to be involved in the regulation of inflammatory responses by Nrf2.

Caffeic Acid Phenyl Ester (CAPE) Protects against Iron-Mediated Cellular DNA Damage through Its Strong Iron-Binding Ability and High Lipophilicity

Caffeic acid phenethyl ester (CAPE) and its structurally-related caffeic acid (CA), ferulic acid (FA) and ethyl ferulate (EF) are constituents of honeybee propolis that have important pharmacological activities. This study found that CAPE—but not CA, FA, and EF—could effectively prevent cellular DNA damage induced by overloaded iron through decreasing the labile iron pool (LIP) levels in HeLa cells. Interestingly, CAPE was found to be more effective than CA in protecting against plasmid DNA damage induced by Fe(II)–H2O2 or Fe(III)–citrate–ascorbate-H2O2 via the inhibition of hydroxyl radical (•OH) production. We further provided more direct and unequivocal experimental evidences for the formation of inactive CAPE/CA–iron complexes. CAPE was found to have a stronger iron-binding ability and a much higher lipophilicity than CA. Taken together, we propose that the esterification of the carboxylic moiety with phenethyl significantly enhanced the iron-binding ability and lipophilicity of CAPE, which is also responsible for its potent protection against iron-mediated cellular DNA damage. A study on the iron coordination mechanism of such natural polyphenol antioxidants will help to design more effective antioxidants for the treatment and prevention of diseases caused by metal-induced oxidative stress, as well as help to understand the structure–activity relationships of these compounds.

Investigating the Relationship Between Water Production and Interfacial Activity of Γ-oryzanol, Ethyl Ferulate, and Ferulic Acid During the Peroxidation of Bulk Oil

In this study, lecithin (as a surfactant) was added to promote the inhibitory-mechanism of γ-oryzanol, ethyl-ferulate and ferulic acid (based on the interfacial phenomena) so as to inhibit the oxidation of stripped sunflower oil. Monitoring the amount of water production as a byproduct of oxidation showed that the water content of the lipid system increased remarkably through the oxidation progress. Lecithin enhanced the critical concentration of hydroperoxides in reverse micelles, compared to the basic state (14.8 vs. 9.2 mM), thereby improving the hydrogen-donating mechanism of antioxidants. The size of reverse micelles increased progressively during the oxidation, while two breakpoints were pointed out in the micelles growth, i.e. at the end of the initiation and the propagation phases. Based on the kinetic data, ferulic acid showed the highest antioxidant activity (23.4), compared to ethyl-ferulate (15.5) and γ-oryzanol (13.7). Generally, lecithin enhanced antioxidant activity (~65%) by improving the interfacial performance of antioxidants.