Protocatechuic Acid Concentration Research Articles

Core-shell structured alginate-based hydrogel beads modified by starch and protocatechuic acid: Preparation, characterization, phenolic slow release and stable antioxidant potential

A novel core-shell structured alginate-based hydrogel bead modified by co-gelatinizing with starch and protocatechuic acid (PA), was designed to modulate physical properties of beads, release behavior and antioxidant stability of encapsulated bioactives. Core was fabricated by ionotropic gelation, and its formulation (ratio of sodium alginate/starch) was determined by particle size/starch distribution, texture and bioactive encapsulation capacity of core. Then, coating core with shell-forming solution co-gelatinized with different doses of PA, and subsequently cross-linked with Ca2+ to obtain core-shell structured beads. Surface microstructure, mechanical characteristics, and swelling ratio of beads were affected by concentrations of PA. Besides, core-shell structure containing PA could enhance delivery and sustained release of encapsulated phenolic bioactives during in vitro digestion, and improve their antioxidant potential stability. Furthermore, interaction between PA and polysaccharide components was elucidated by FTIR and TGA. The present information was beneficial for the advancement of functional food materials and bioactive delivery systems.

Enhancing productivity, modifying biochemical parameters, and regulating the phenylpropanoid pathway in 'Le-Conte' pears through optimal protocatechuic acid treatments

BackgroundThis study aimed to investigate the impact of protocatechuic acid (PRC) treatments on the productivity and fruit quality of 'Le-Conte' pears, with a specific focus on productivity, stone cells content, and antioxidant activity. The research spanned over three consecutive cultivating seasons, with the first season serving as a preliminary study to determine the optimal PRC concentrations and the most effective number of spray applications. During the initial season, response surface methodology (RSM) was employed to optimize PRC concentration and application frequency. PRC was evaluated at concentrations ranging from 50 to 400 ppm, with treatment frequencies of either once or twice. Considering the optimal conditions obtained from RSM results, PRC treatments at 200 ppm and 300 ppm were applied twice, and their respective effects were studied in comparison to the control in the following seasons.ResultsRSM results indicated that PRC at 200 and 300 ppm, applied twice, once during full bloom and again three weeks later, yielded the most significant effects. Subsequent studies revealed that PRC treatments had a substantial impact on various aspects of fruit production and quality. Applying 300 ppm PRC once during full bloom and again three weeks later resulted in higher fruit set percentages, lower fruit abscission, and enhanced fruit yield compared to untreated trees. Additionally, the 200 ppm PRC treatment maintained physicochemical characteristics such as fruit color, increased total soluble solids (TSS), and total sugar, and maintained higher ascorbic acid content and antioxidant capacity in the fruits while reducing stone cells content and lignin. Notably, enzyme activities related to phenylpropanoid metabolism and stone cells, including phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-Coumarate-CoA Ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), and cinnamoyl-CoA reductase (CCR), as well as peroxidase, polyphenol oxidase, and laccase, were significantly regulated by PRC treatments.ConclusionOverall, this study suggests that PRC treatments are suitable for enhancing pear yield and quality, with PRC at 200 ppm being the more recommended option over 300 ppm. This approach serves as an effective strategy for achieving a balance between enhancing the productivity and fruit quality of 'Le-Conte' pears.

Fermentation of Chenopodium formosanum Leaf Extract with Aspergillus oryzae Significantly Enhanced Its Physiological Activities

Chenopodium formosanum Koidz (CF) is an indigenous cereal plant of Taiwan. Its high content of secondary metabolites and nutrients has attracted attention for its use in skin care products and functional foods. However, most studies have focused on the extract of CF seeds, which are relatively expensive, and none have investigated the effects of combining extraction and fermentation. In this study, we evaluated the utility of using extracts of different parts of CF, i.e., the leaves, stems, and unhulled and hulled seeds. We first made aqueous, ethanolic, methanolic, and ethyl acetate extracts of the four parts. After assessing their biological activities, we selected only unfermented and fermented CF leaf methanolic extracts for subsequent analysis. None of the concentrations of fermented CF leaf extract (≤400 mg/L) were cytotoxic, and all exhibited antioxidative, anti-inflammatory, antimicrobial, skin-whitening, moisturizing, and antiaging activities. The concentrations of protocatechuic acid, epicatechin, gallic acid, and quercetin increased the most after fermentation. Therefore, they were subjected to a molecular docking analysis, which revealed that quercetin and epicatechin may contribute the most to skin-whitening and antiaging properties, respectively. In conclusion, fermented CF leaf methanolic extracts can be useful as a functional ingredient in health foods, botanical drugs, and cosmetic products.

Phenolic and free amino acid profiles of bee bread and bee pollen with the same botanical origin – similarities and differences

In this study, the chemical profile of bee pollen (BP) and bee bread (BB) samples collected from the same beehive were analyzed by LC–MS/MS (liquid chromatography technique coupled with tandem mass spectrometry), providing the identification of 23 phenolic compounds and 42 free amino acids (FAAs). Rutin was the phenolic compound with the highest rate of occurrence in both BP and BB samples. However, concentrations of protocatechuic acid, 2,5-dihydroxybenzoic acid and kaempferol compounds were significantly higher in BB samples than in BP samples from the same hive probably as result of microbial activity and glycosides degradation. The obtained data revealed that the phenolic profiles of the samples differ not only by the type of a product but also by region. Among FAAs proline was the predominant compound in all the analyzed BP and BB samples followed by l-asparagine (BP samples) and l-aspartic acid (BP and BB samples). A high content of proline can be used as a parameter of sample freshness. Also, Principal Component Analysis (PCA) and Cluster analysis proved the possibility of using phlorizin as a chemotaxonomic marker for Rosaceae (Malus or Prunus genus) pollen presence in BP1 sample. In addition, amino acid profile had higher impact on BP and BB sample differentiation due to lower FAAs content in BB samples probably caused by microbial activity. To the best of our knowledge, this study is the first to compare the individual phenolic compounds and free amino acids of bee pollen and bee bread samples with the same botanical origin (predominantly originated from plants belonging to the following families: Asteraceae, Fabaceae, Plantaginaceae and Rosaceae).

Polyphenolic composition of grape stems

This study is focused on the study of polyphenolic compounds in grape stems as by-product of winemaking industry. Two white varieties of Grüner Veltliner and Sauvignon and two red varieties of Blauer Portugieser and Cabernet Moravia were selected for the study. Antioxidant activity, concentration of total polyphenols and concentration of individual phenolic compounds were determined. The results show a higher concentration of polyphenols and higher values of antioxidant activity in red varieties. The Blauer Portugieser variety contained the highest concentrations of syringic acid 1.346 mg.L-1, caffeic acid 20 mg.L-1, ferulic acid 1.192 mg.L-1, coumaric acid 3.231 mg.L-1, trans-resveratrol 14.195 mg.L-1, catechin 79.314 mg.L-1 and epicatechin 33.205 mg.L-1. Cabernet Moravia contained the highest concentration of protocatechuic acid 1.201 mg.L-1, the Sauvignon variety reached the highest concentration of gallic acid 4.015 mg.L-1 and hydroxybenzoic acid 0.076 mg.L-1. The highest values of alpha-amino acids were determined in the Blauer Portugieser variety 165.3 mg L-1 and the lowest in the Grüner Veltliner variety 33.3 mg L-1. The highest concentration of ammonia nitrogen was 214 mg L-1 for the Blauer Portugieser variety and the lowest concentration of ammonia nitrogen was measured in Cabernet Moravia 35.7 mg L-1.

Reactive separation of protocatechuic acid using Tri-n-octyl amine and Di-(2-ethylhexyl) phosphoric acid in Methyl isobutyl ketone

Abstract Protocatechuic acid is used extensively in pharmacological and related industries which can also be obtained by fermentation. Reactive separation by means of reactive extractant is a favourable alternative to recover carboxylic acids from the aqueous dilute streams and the fermentation broth. In this paper, the reactive separation of protocatechuic acid were performed by D2EHPA (Di-(2-ethylhexyl) phosphoric acid) and TOA (tri-n-octyl amine) dissolved in MIBK (Methyl isobutyl ketone) at 298 K. Distribution coefficients, degree of extraction, complexation constants and loading ratio were estimated. The equilibrium for protocatechuic acid-extractant-diluent system was represented using Langmuir model, mass action law and relative basicity model. Results obtained from model were found to be close to experimental data. TOA was found more effective than D2EHPA for the recovery of protocatechuic acid having 5.39 as maximum distribution coefficient and 84.36% efficiency at 0.01 mol L−1 and 1.1437 mol L−1 concentration of protocatechuic acid and TOA respectively.

Selective fractionation of supercritical extracts from leaves of Baccharis dracunculifolia

Baccharis dracunculifolia is a plant native to Brazil, rich in phenolic compounds such as 3,5-diprenyl-4-hydroxycinnamic acid (artepillin C), a derivative of cinnamic acid, and 4-methoxy-3,5,7-trihydroxyflavone (kaempferide), a flavonoid. This study evaluated the performance of supercritical carbon dioxide (scCO2) as solvent for selective fractionation by precipitation from a supercritical extract of B. dracunculifolia using scCO2 pressure reduction in a sequence of separators to obtain different extract fractions in relation to its composition. The extracts and fractions were analyzed in terms of overall yield, antioxidant activity and concentration of protocatechuic acid, caffeic acid, sinapic acid, chrysin, p-coumaric acid, kaempferide and artepillin C. High concentrations were observed of the two major compounds (kaempferide and artepillin C) in the extract fractions of the first two separators. However, the aqueous extract obtained in the third step presented better antioxidant activity when compared the other fractions. Also obtained was a volatile fraction composed mainly of sesquiterpenes.

Phenolic profiles, antioxidant capacity, and acetylcholinesterase inhibitory activity of eight South African seaweeds

In the search for new, safe, and natural sources as antioxidant and acetylcholinesterase (AChE) inhibitors, eight seaweeds were collected from the intertidal region in KwaZulu-Natal, South Africa and screened. Their total phenolic, flavonoid, and condensed tannin contents were determined, and the specific phenolic acids were identified. The highest total phenolics, flavonoids, and condensed tannin were recorded in Rhodomelopsis africana (7.89 mg gallic acid equivalents g−1), Halimeda cuneata (3.64 mg catechin equivalents g−1), and Codium duthieae (0.60 mg cyanide chloride equivalents g−1), respectively. Based on UHPLC-MS/MS, different concentrations of protocatechuic acid, p-hydroxybenzoic acid, and m-hydroxybenzoic acid were quantified in the seaweeds. The highest radical scavenging ability and oxygen radical absorbance capacity (ORAC) were observed in red Gelidium foliaceum (52.2 %) and green C. duthieae (44 μmol TE g−1), respectively. In terms of AChE inhibition, the green H. cuneata exhibited greatest bioactivity (IC50 = 70 μg mL−1). Overall, the findings suggest that these seaweeds could be potential candidates as new sources of natural antioxidant and AChE inhibitors.

Phenolic Acid Content and Free Radical-Scavenging Activity of Two Differently Processed Carob Tree (<i>Ceratonia siliqua</i> L.) Pod

The phenolic acids in free phenolic acid (FPHA), methanol-soluble phenolic ester (MSPE), and methanol-soluble phenolic glycoside (MSPG) fractions of two carob products, natural carob-pod flour (CPF) and commercial carob-pod flour (CCPF), were identified and quantified using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Six phenolic acids were identified in the carob flours (gallic acid, protocatechuic acid, gentisic acid, syringic acid, p- coumaric acid, and sinapic acid). Gallic acid was the major phenolic acid; and its concentrations in CCPF were substantially higher than in CPF (135 - 166 and 85.2 - 91.3 mg/g dw, respectively). The concentrations of p-coumaric acid and sinapic acid were also higher in CCPF than in CPF. In contrast, the concentrations of protocatechuic acid and gentisic acid were generally lower in CCPF than in CPF, with the only exception being gentisic acid glycosides. Both carob-pod flours contained almost the same amount of sinapic acid and syringic acid. The total phenolic contents of the FPHA, MSPE, and MSPG fractions of CPF were found to be 44%, 38%, and 69% that of the respective fractions of CCPF. Correspondingly, the FPHA, MSPE, and MSPG fractions of CCPF had higher free radical-scavenging activity (28.4%, 33.1%, and 26.2%, respectively) than the corresponding fractions of CPF (9.2%, 28.0%, and 9.2%, respectively). Notably, the FPHA and MSPG fractions of each sample had very similar scavenging activity while the MSPE fraction always had higher activity. The FPHA and MSPG fractions of CPF had the lowest activities.

Phytochemical composition and antioxidant activity of peach as affected by pasteurization and storage duration

Fruit are very perishable and are often preserved as heat-processed foods. Clingstone peach [Prunus persica (L.) Batsch ‘Catherine’] fruit were heat-treated at 90 °C for 5 min and stored under aseptic conditions at room temperature (ca. 22 °C) for 90 days. Significant reductions in total carotenoids were observed immediately after pasteurization but total antioxidant activity and the concentration of total phenolics were unaffected. Pasteurization induced significant reductions in the concentration of protocatechuic acid (from 10.2 to 5.8 μg/g fw), zexanthin and β-cryptoxanthin. Significant reduction in antioxidant activity, expressed as ascorbic acid equivalents, from 0.52 to 0.25 mg/g fw, was observed during storage of pasteurized peach for 90 days. Total phenolics, expressed as gallic acid equivalents, decreased during storage from 0.57 to 0.28 mg/g fw and total carotenoids decreased from 4.0 to 1.3 μg/g fw. Procyanidin B1 increased from 15.8 to 26.8 μg/g fw and chlorogenic acid and neochlorogenic acid increased 35 and 43%, respectively. (−)-Epicatechin decreased during storage from 13.1 to 4.0 μg/g fw and quercetin-3-glucoside from 7.3 to 4.4 μg/g fw. All carotenoids decrease significantly with the exception of zeaxanthin, which increased during storage. Storage duration strongly affected the concentration of phenolics and carotenoids in pasteurized peach.

UPLC simultaneous determination of five active components in Cinnamomi Ramulus

A rapid UPLC method for simultaneous determination of protocatechuic acid, coumarin, cinnamic alcohol, cinnamic acid and cinnamaldehyde in Cinnamomi Ramulus was established. The optimal conditions of separation and detection were achieved on an HSS T3 Column (2.1 mm x 100 mm, 1.8 microm) eluted with a gradient of acetonitrile and 0.05% aqueous phosphoric acid, at a flow rate of 0.5 mL x min(-1), detected at 254 nm. The linear response ranges of protocatechuic acid, coumarin, cinnamic alcohol, cinnamic acid and cinnamaldehyde were 0.359-3.59 mg x L(-1) (r = 0. 999 3), 2. 834-28.34 mg x L(-1) (r = 0.999 8), 0.574-5.74 mg x L(-1) (r = 0.999 8), 2.400-24.00 mg x L(-1) (r = 0.999 9), 32.57-325.7 mg x L(-1) (r = 0.999 8), respectively (n = 6). The mean recoveries (n = 9) of the five components were 96.7%-101.0%, RSD < 2.3%. The assay demonstrates that the method has adequate accuracy and selectivity to measure the concentration of protocatechuic acid, coumarin, cinnamic alcohol, cinnamic acid and cinnamaldehyde in Cinnamomi Ramulus.

The effect of nitrogen fertilization on fungistatic phenolic compounds in roots of beech (Fagus sylvatica) and Norway spruce (Picea abies)

SummaryThe effect of nitrogen fertilization on fungistatic phenolic compounds in fine roots of beech and Norway spruce growing in afforestation plots was analysed. The plots were situated at two sites in Switzerland on acidic soil with low base saturation. For 9 years, the trees have been treated with dry ammonium nitrate to give 0, 10, 20, 40, 80, 160 kg N ha−1 year−1, respectively. The phenolic compounds responded differently to fertilization. Fine roots of beech showed a significant decrease of (−)‐epicatechin and piceatannol with increasing nitrogen fertilization. The concentration of protocatechuic acid was increased with fertilization. Roots of fertilized Norway spruce showed significantly decreased concentrations of 4‐hydroxyacetophenone and piceatannol. The mycelial growth of three isolates each of Heterobasidion annosum s.l. and Cylindrocarpon destructans was tested on agar media containing various phenolic compounds in concentrations found in fine roots of Norway spruce (Picea abies) and beech (Fagus sylvatica). All three H. annosum isolates were inhibited by p‐coumaric acid and (−)‐epicatechin. Two isolates were inhibited by another four phenolic compounds (p‐hydroxybenzoic acid, 4‐hydroxyacetophenone, piceatannol and protocatechuic acid), one by (+)‐catechin. Two of three C. destructans isolates were inhibited by all phenolic compounds except for (+)‐catechin which affected only one isolate, one isolate did not respond at all.

Changes in the alkaline-labile phenolic compounds of wheat straw cell walls as affected by SO 2 treatment and passage through the gastro-intestine of sheep

Sheep were fed two rations based on untreated (WS) and SO 2-treated (SO 2-WS) wheat straw, and the effect of chemical treatment and passage through the gastro-intestine on the composition and degradation of ester and ether-linked cell wall (CW) phenolics was studied. The SO 2 treatment reduced the content of total ferulic acid (FA) and p-coumaric acid (PCA) by 35% while tripling the level of vanillin and increasing by 40% the concentration of protocatechuic acid. In WS most of the phenolic compounds were CW-bound, but 37% of the vanillic and 88% of the protocatechuic acids were in the alcohol soluble (AS) fraction. The solubilising effect of the treatment was expressed in releasing the phenolics from the CW mainly as AS-lignins. Most of the FA (62%) was ether-linked, whereas most of the PCA (78%) was ester-linked in the CW of WS. The other minor components were either entirely or mostly, etherified units. The SO 2 treatment was more effective in cleaving the ester than the ether bonds of the cinnamic acids. Ester-linked FA was more extensively degraded in the rumen than ester-linked PCA. Ester-linked FA and PCA were more extensively degraded in the rumen than the respective ether-linked compounds. Nevertheless, substantial amounts of ether-linked FA, PCA and other phenolics were removed from CW in the rumen, most likely as oligo-lignols. Phenolic compounds were determined in rumen liquor of sheep fed the WS and WS-SO 2 rations. FA was not detected and PCA was at a very low (20–40 μM) concentration. Phenyl-propanoic acid (PPA) was the major monomeric phenolic compound detected, at concentrations of 580 and 380 μM in the rumen of WS and WS-SO 2 sheep, respectively. It is suggested that hydrogenation of PCA and combined hydrogenation and demethoxylation of FA were responsible for the production of PPA in the rumen.

Phytotoxic Phenolic Compounds in Sericea Lespedeza Residues1

AbstractSericea lespedeza (Lespedeza cuneata) stem residues incorporated into soils were effective in depressing corn growth.Four phenolic compounds—protocatechuic acid, vanillin, ferulic acid, and p‐coumaric acid—were detected by thin layer or gas chromatographic techniques in sericea residues. Stems contained the greatest amount of these compounds.Higher concentration of protocatechuic acid than other phenolic compounds was detected. The protocatechuic acid appeared to be less effective in inhibiting auxin activity of indoleacetic acid in Avena coleoptiles than the smaller concentrations of vanillin, ferulic acid, and p‐coumaric acid.