Antibacterial Properties of Coaxial Spinning Membrane of Methyl ferulate/zein and Its Preservation Effect on Sea Bass

Methyl ferulate is a new natural antibacterial agent with strong activity and low toxicity. It has good application prospects in food preservation. In this paper, the antibacterial activity of methyl ferulate against Shigella putrefaciens was verified, and it was embedded into zein by electrospinning technology to prepare fiber membranes. The addition of methyl ferulate could improve the tensile strength of zein fiber membrane and decrease the crystallinity of the membrane, which was mainly a physical combination. The fiber membrane improved the thermal stability of methyl ferulate. The water contact angle (WCA) decreased to 54.85°. The results showed that methyl ferulate in fiber membrane could be released slowly, gradually exerting its antibacterial activity. After coating perch with methyl ferulate/zein fiber membrane, the growth of microorganisms in perch meat was inhibited, and the pH value and total volatile basic nitrogen (TVB-N)content were effectively increased. In a word, methyl ferulate had antibacterial activity in the fiber film, which was able to achieve a sustained release effect in the process of fish packaging, prolonging its antibacterial activity, and having preservation effect on sea bass; thus, it could be used in food packaging.

Characterization of Feruloyl Esterase from Bacillus pumilus SK52.001 and Its Application in Ferulic Acid Production from De-Starched Wheat Bran

Feruloyl esterase (FAE; EC 3.1.1.73) catalyzes the hydrolysis of the 4-hydroxy-3-methoxycinnamoyl group in an esterified sugar to assist in waste biomass degradation or to release ferulic acid (FA). An FAE-producing strain was isolated from humus soil samples and identified as Bacillus pumilus SK52.001. The BpFAE gene from B. pumilus SK52.001 was speculated and heterogeneously expressed in Bacillus subtilis WB800 for the first time. The enzyme exists as a monomer with 303 amino acids and a molecular mass of 33.6 kDa. Its specific activity was 377.9 ± 10.3 U/ (mg protein), using methyl ferulate as a substrate. It displays an optimal alkaline pH of 9.0, an optimal temperature of 50 °C, and half-lives of 1434, 327, 235, and 68 min at 50, 55, 60, and 65 °C, respectively. Moreover, the purified BpFAE released 4.98% FA of the alkali-acidic extractable FA from de-starched wheat bran (DSWB). When the DSWB was enzymatically degraded by the synergistic effect of the BpFAE and commercial xylanase, the FA amount reached 49.47%. It suggested that the alkaline BpFAE from B. pumilus SK52.001, which was heterologously expressed in B. subtilis WB800, possesses great potential for biomass degradation and achieving high-added value FA production from food by-products.

Bioactivity and Molecular Docking Studies of Derivatives from Cinnamic and Benzoic Acids

Over the last decade, there has been a dramatic increase in the prevalence and gravity of systemic fungal diseases. This study aimed therefore at evaluating the antifungal potential of ester derivatives of benzoic and cinnamic acids from three Candida species. The compounds were prepared via Fischer esterification, and the antifungal assay was performed by the microdilution method in 96-well microplates for determining the minimal inhibitory concentrations (MICs). The findings of the antifungal tests revealed that the analogue compound methyl ferulate, methyl o-coumarate, and methyl biphenyl-3-carboxylate displayed an interesting antifungal activity against all Candida strains tested, with MIC values of 31.25-62.5, 62.5-125, and 62.5 μg/ml, respectively. A preliminary Structure-Activity Relationship study of benzoic and cinnamic acid derivatives has led to the recognition of some important structural requirements for antifungal activity. The results of molecular docking indicate that the presence of the enoate moiety along with hydroxyl and one methoxy substitution in the phenyl ring has a positive effect on the bioactivity of compound 7 against Candida albicans. These observations further support the hypothesis that the antifungal activity of compound 7 could be due to its binding to multiple targets, specifically to QR, TS, and ST-PK. Additional experiments are required in the future to test this hypothesis and to propose novel compounds with improved antifungal activity.

Optimization of the Reaction Conditions for the Synthesis of Dihydrobenzofuran Neolignans

We have optimized the experimental conditions for the silver(I)-promoted oxidative coupling of methyl <i>p</i>-coumarate (<b>I</b>) and methyl ferulate (<b>II</b>), which is the most frequently used methodology to synthesize the bioactive dihydrobenzofuran neolignans <b>1</b> ((±)-<i>trans</i>-dehydrodicoumarate dimethyl ester) and <b>2</b> ((±)-<i>trans</i>-dehydrodiferulate dimethyl ester). Most of the tested conditions affected the conversion (i.e., the consumption of <b>I</b> and <b>II</b>) and the selectivity (i.e., the percentage of <b>I</b> and <b>II</b> that was converted into <b>1</b> and <b>2</b>, respectively), so the optimized conditions were the conditions that afforded the best balance between conversion and selectivity. Silver(I) oxide (0.5 eq) is the most efficient oxidant agent amongst the silver(I) reagents that were tested to convert methyl esters <b>I </b>and <b>II </b>into compounds <b>1</b> and <b>2</b>, respectively. Acetonitrile, which has not yet been reported as a solvent for this reaction, provided the best balance between conversion and selectivity, besides being “greener” than other solvents that are more often employed (e.g., dichloromethane and benzene). Under the optimized conditions, the reaction time decreased from 20 h to 4 h without significantly impacting the conversion and selectivity. However, the relation between the results obtained by adding a radical initiator (AIBN) or a radical inhibitor (isoquinoline) and the previously reported involvement of radical intermediate species in the silver(I)-promoted oxidative coupling of <b>I</b> and <b>II</b> is not clear and deserves further investigation.

Optimization of the Reaction Conditions for the Synthesis of Dihydrobenzofuran Neolignans

We have optimized the experimental conditions for the silver(I)-promoted oxidative coupling of methyl <i>p</i>-coumarate (<b>I</b>) and methyl ferulate (<b>II</b>), which is the most frequently used methodology to synthesize the bioactive dihydrobenzofuran neolignans <b>1</b> ((±)-<i>trans</i>-dehydrodicoumarate dimethyl ester) and <b>2</b> ((±)-<i>trans</i>-dehydrodiferulate dimethyl ester). Most of the tested conditions affected the conversion (i.e., the consumption of <b>I</b> and <b>II</b>) and the selectivity (i.e., the percentage of <b>I</b> and <b>II</b> that was converted into <b>1</b> and <b>2</b>, respectively), so the optimized conditions were the conditions that afforded the best balance between conversion and selectivity. Silver(I) oxide (0.5 eq) is the most efficient oxidant agent amongst the silver(I) reagents that were tested to convert methyl esters <b>I </b>and <b>II </b>into compounds <b>1</b> and <b>2</b>, respectively. Acetonitrile, which has not yet been reported as a solvent for this reaction, provided the best balance between conversion and selectivity, besides being “greener” than other solvents that are more often employed (e.g., dichloromethane and benzene). Under the optimized conditions, the reaction time decreased from 20 h to 4 h without significantly impacting the conversion and selectivity. However, the relation between the results obtained by adding a radical initiator (AIBN) or a radical inhibitor (isoquinoline) and the previously reported involvement of radical intermediate species in the silver(I)-promoted oxidative coupling of <b>I</b> and <b>II</b> is not clear and deserves further investigation.

Constituents from the Seeds of Sophora Alopecuroides L.

Three new isoflavone glucosides, kudonol A−C (1–3), two new ester derivatives of phenylpropanoid, kudolignan A and B (4–5) and five known compounds, (−)-maackiain (6), neoliquiritin (7), methyl 4-coumarate (8), methyl ferulate (9) and (+)-wikstromol (10), were isolated from an extract of dried seeds of the traditional Chinese medicinal plant Sophora alopecuroides L. Their structures were established by NMR and HRESIMS data analyses. The monosaccharide part’s configuration of isoflavone glucosides was confirmed by acid hydrolysis and analyzed by a JAsco OR-4090 chiral detector, comparing it to standard substance D-glucose. The cytotoxicity effects against HeLa, Hep3B, MCF-7 and H1299 cells were tested by CCK-8 assay.

Characterizing the interaction between methyl ferulate and human serum albumin by saturation transfer difference NMR

STD-NMR technique characterized the recognition mechanism of methyl ferulate and human serum albumin qualitatively and quantitatively.

Secondary Metabolites from Indonesian Kigelia africana (Bignoniaceae)

From the fruit of Kigelia africana three fractions of secondary metabolites were isolated. Fraction 1 (CD-1) was characterized by using UV-Vis, FTIR, 1D and 2D NMR and MS, meanwhile fraction 2 (CD-2) and 3 (B-1) were characterized by LCMS and compared with literature. All these fractions were screened for anticancer activity by using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method to calculate IC50 toward Michigan Cancer Foundation-7 MCF-7 breast cancer and menogaril-resistant mouse leukemia P388 cells. Based on spectroscopic data, CD-1 fraction was identified as methyl ferulate (1). On the other hand, the B-1 and CD-2 fraction did not pure, yet. Based on LCMS data that analyzed by chemspider and masslink software, CD-2 fraction was estimated as compound mixture with dominant compounds like viscumside (2), specioside (3), caffeic acid glucoside (4), ferulic acid (5), meanwhile B-1 fraction was estimated as compound mixture with dominant warfarin alcohol (6), p-Coumaroyl glucose (7) and β - Sitosterol (8) compounds. Nevertheless, all isolated fractions did not show anticancer activity towards both the cancer cells since it had different constituent compared with previous results.