Acid Phenolic Compounds Research Articles

Chemical Composition, In vitro and In silico Evaluation of Essential Oil Extracted from Mentha Piperita L. for Lung Cancer

Background: Mentha piperita, a naturally occurring herb, is utilized in medicinal formulations. It possesses abundant bioactive elements, including flavonoids and phenolic acid compounds,that exhibit various properties such as antioxidants, anti-inflammatory and anti-cancer. Objective: In the present study, chemical constituents of essential oil extracted from Mentha piperita were analyzed and identified through GC-MS. In vitro antiproliferative activity was performed on A549 lung cancer cell line lines. In silico study was conducted by Schrodinger’s Maestro’s software to identify chemical constituents in the plant as potential EGFR (Epidermal Growth Factor Receptors) inhibitors Methods: Hydro-distilled essential oil was analyzed by GC-MS to identify chemical components based on the retention index and mass fragmentation pattern, which was then tested for its antiproliferative activity by MTT assay against human lung cancer cell lines. All the identified constituents were investigated in silico for their affinity towards EGFR (Epidermal Growth Factor Receptors). Results: A total of thirty constituents were identified where D-carvone (56.69%), L-limonene (12.36%), squalene (3.36%), cis-carveol (2.93%), and α-amorphene (2.36%) were observed as major constituents of the essential oil. The essential mentha oil also exhibited antiproliferative activity against lung cancer cell lines with an IC50 value of 86.05 µg/ml. Furthermore, from the in silico study, five constituents were identified to have a better affinity for EGFR (Epidermal Growth Factor Receptors) than that of the standard drug Osimertinib. Conclusion: In the present study, the aerial part of the plant Mentha piperita was hydrodistilled.Thirty phytoconstituents were identified through GC-MS data. An in-silico study was performed using Schrodinger software, and a further in vitro study was performed in which essential oil showedgood antiproliferative activity against the A549 cancer cell line.

Pharmacological activity, phytochemistry, and organ protection of lithospermic acid.

Lithospermic acid (LA) is a water-soluble phenolic acid compound extracted and separated from the dried root and the rhizome of Salviamiltiorrhiza Bge (Labiatae), possessing multiple biological activities. Firstly, in terms of pharmacological activities, LA has been proven to possess anti-inflammatory, antioxidant, autophagy activation, and antiapoptotic properties. Secondly, the pharmacokinetic characteristics of LA show rapid and extensive distribution in various tissues after intravenous administration, followed by rapid elimination and excretion. Additionally, potential therapeutic effects of LA have been found in various diseases such as thrombosis, Parkinson's disease, hepatitis B, diabetes, and psoriasis, among others. Particularly, LA has shown promising prospects in the treatment of clinical heart diseases and has been included in new drug formulations for the treatment of chronic angina, demonstrating superior efficacy compared to current cardiovascular drugs. In conclusion, this review comprehensively introduces the pharmacological mechanisms, pharmacokinetics, and protective effects in diseases of LA. These information can lay a theoretical foundation for the future development and new clinical applications of LA.

Isolation of Allelochemicals from Rhododendron capitatum and Their Allelopathy on Three Perennial Herbaceous Plants.

Rhododendron capitatum community expansion is a major threat to alpine meadow. Allelopathy is an important mediator in managing relationships between plants in natural ecosystems. However, allelopathy and specific allelochemicals of R. capitatum have not been studied yet. In this study, the allelopathy of the foliage litter of R. capitatum was explored on Elymus nutans, Poa pratensis and Medicago ruthenica, and the chemical composition and their allelopathy were studied. The results showed that the aqueous extract of the foliage litter of R. capitatum had an allelopathy of "low concentration promotion and high concentration inhibition" on the germination of E. nutans, P. pratensis, and M. ruthenica. Organic acids, fatty acids, terpenes, phenols, and phenolic acid compounds were identified, with Zanamivir (77.81%), alpha-linolenic acid (18%), Kaurenoic acid (23.50%), 4-hydroxyphenylglycolic acid (21.54%), and Quinic acid (28.24%) having the highest relative content, and all five compounds showed significantly inhibitory effects on seed germination and seedling growth of E. nutans, P. pratensis, and M. ruthenica, which further suggests that the five compounds are the critical allelochemicals for negative allelopathy of R. capitatum. These results highlight the crucial role of inhibitory allelopathy produced by R. capitatum in the establishment and expansion of its populations.

A Diboronic Acid-Based Fluorescent Sensor Array for Rapid Identification of Lonicerae Japonicae Flos and Lonicerae Flos.

Lonicerae japonicae flos (LJF) and Lonicerae flos (LF) are traditional Chinese herbs that are commonly used and widely known for their medicinal properties and edibility. Although they may have a similar appearance and vary slightly in chemical composition, their effectiveness as medicine and their use in clinical settings vary significantly, making them unsuitable for substitution. In this study, a novel 2 × 3 six-channel fluorescent sensor array is proposed that uses machine learning algorithms in combination with the indicator displacement assay (IDA) method to quickly identify LJF and LF. This array comprises two coumarin-based fluorescent indicators (ES and MS) and three diboronic acid-substituted 4,4'-bipyridinium cation quenchers (Q1-Q3), forming six dynamic complexes (C1-C6). When these complexes react with the ortho-dihydroxy groups of phenolic acid compounds in LJF and LF, they release different fluorescent indicators, which in turn causes distinct fluorescence recovery. By optimizing eight machine learning algorithms, the model achieved 100% and 98.21% accuracy rates in the testing set and the cross-validation predictions, respectively, in distinguishing between LJF and LF using Linear Discriminant Analysis (LDA). The integration of machine learning with this fluorescent sensor array shows great potential in analyzing and detecting foods and pharmaceuticals that contain polyphenols.

A stationary phase of tetraethylene glycol-modified silica for separation of phenolic acids

AbstractSilica, as a stationary phase, has low separation efficiency accompanied by overlapping, broadened, and tailed peaks, so it needs to be modified to improve its efficiency. This study aims to develop a silica-based stationary phase modified by tetraethylene glycol (TEG) to separate phenolic compounds. Silica was modified by a chemical bond between silanol groups on the silica surface and TEG through a 3-glycidyloxypropylmethoxysilane reaction. The modified silica was packed into a capillary column and used to separate simple phenolic compounds consisting of phenol, pyrocatechol, and pyrogallol. A sample of 0.2 µL was injected into the capillary liquid chromatography and the mobile phase employed was acetonitrile 98% with a flow rate of 3 μL min−1. Elution was also done isocratically in this process and detection was carried out at a wavelength of 254 nm. The mixture of simple phenolic compounds was successfully separated in less than 7 min. The asymmetry factor and resolution were 1.43–2.12 and 1.72–5.43 respectively. The number of the theoretical plates ranged from 213 to 7,857. Columns containing Si-TEG stationary phase also separate phenolic compounds, which consist of gallic acid, syringic acid, ferulic acid, and caffeic acid. A sample of 0.2 µL was injected into the capillary liquid chromatography and successfully separated the mixture in less than 12 min. The samples were eluted isocratically using a mixture of methanol and 50 mM phosphate buffer pH 2.5 (8:92) with a flow rate of 3 μL min−1. The phenolic acids compounds were detected at a wavelength of 280 nm. The chromatogram showed four separate peaks. The asymmetry factor and resolution were 1.53–1.63 and 1.14–1.74, respectively, but the number of the theoretical plates was low, ranging from 190 to 796.

Calcium signaling regulates the accumulation of phenolic acids in response to UV-B stress in Rhododendron chrysanthum Pall.

This study, using multi-omics combined with physiologic assays, found that calcium-ion signaling can regulate phenolic acid accumulation in R. chrysanthum leaves in response to UV-B stress. UV-B stress is a severe abiotic stress capable of destroying cellular structures and affecting plant growth. Rhododendron chrysanthum Pall. (R. chrysanthum) is a plant that has been exposed to high levels of UV-B radiation for an extended period, leading to the development of adaptive responses to mitigate UV-B stress. As such, it serves as a valuable experimental material for studying plant resilience to UV-B stress. We utilized R. chrysanthum as the experimental material and subjected it to UV-B stress. We conducted a comprehensive analysis of the changes in R. chrysanthum under both control and UV-B stress conditions using multi-omic and physiologic assays. Our aim was to investigate the molecular mechanism underlying R. chrysanthum's resistance to UV-B stress, with a focus on calcium-ion signaling. UV-B stress was found to impact the photosynthesis of R. chrysanthum by decreasing the maximum photosynthetic efficiency of photosystem II, reducing Fm, and increasing F0. In addition, the composition of numerous phenolic acid compounds was significantly altered. Genes and proteins related to calcium signaling showed significant differences, with some proteins (CML, CPK1, CRK3, ATP2C, ERG3, CAR7) being modified by acetylation. The correlation between genes and proteins involved in calcium signaling and phenolic compounds suggested that calcium signaling may play a role in regulating the accumulation of phenolic compounds under UV-B stress to help R. chrysanthum adapt. This study examines the impact of calcium-ion signaling on the accumulation of phenolic acid compounds, offering insights for future research on the molecular mechanisms underlying plant resilience to UV-B stress.

OPTIMIZING ANTIOXIDANT POTENTIAL THROUGH MICROENCAPSULATION OF KAFFIR LIME LEAVES EXTRACT (CITRUS HYSTRIX DC) WITH MALTODEXTRIN AND GELATIN

Kaffir lime leaves (Citrus hystrix DC) are a natural antioxidant compound that can ward off free radicals due to the presence of flavonoid compounds. The flavonoids in this plant were extracted by extraction using a maceration method using 70% ethanol solvent with a soaking time of 24 hours. The ratio used between samples and solvent is 1:10. The microencapsulation process uses a drying method using an oven with maltodextrin coating combined with gelatin in the ratio (coating: kaffir lime leaf extract = 1: 2, 2: 2 and 4: 2) and dried using an oven at temperatures of 40℃, 45℃ and 50℃. Encapsulants with a variant ratio (coating: extract = 4:2) with a gelatin weight of 3 grams at a drying temperature of 50℃ showed the best results, namely 69.079%. Based on GC-MS testing, microencapsulated kaffir lime leaf extract contains compounds terpenoid, phenolic and fatty acid compounds. Antioxidant activity was tested using DPPH analysis and obtained an IC50 result of 48.5694 µg/ml. The morphological characteristics of the microencapsulation were tested using Scanning Electron Microscopy (SEM) analysis. The microencapsulation dissolution test showed that all samples disintegrated within 12 minutes. Overall, it can be concluded that microencapsulation made from maltodextrin and gelatin can encapsulate antioxidants in kaffir lime leaf extract well and dissolve easily at room temperature.

The hemostatic molecular mechanism of Sanguisorbae Radix's pharmacological active components based on HSA: Spectroscopic investigations, molecular docking and dynamics simulation

The interactions between human serum albumin (HSA) and the hemostatic components of the Chinese medicine Sanguisorbae Radix (SR), specifically phenolic acid compounds such as caffeic acid (CA), ferulic acid (FA) and their 1:1 mixture (1:1) were studied to investigate the molecular mechanism underlying the hemostatic effect of SR. Network pharmacology combined with the experimental and computational data revealed that HSA is one of the hemostatic targets to SR phenolic acids. SDS-PAGE and multi-spectroscopy demonstrated that the phenolic acids bind to the Sudlow site I on HSA, altering its structure and influencing its migration velocity. There is an observed synergistic effect upon the mixture of CA and FA. Quantum chemistry, molecular docking, and molecular dynamics simulations indicate that the binding of phenolic acids to HSA is stable, and variations in binding efficiency are associated with the hydrophobicity of the substituent at the C3 position of the side chain, and also, the key amino acids and functional groups for hemostasis of SR were identified, along with the active sites that contribute to the synergistic enhancement by phenolic acids.

Transcriptional responses and secondary metabolites variation of tomato plant in response to tobacco mosaic virus infestation

The present study focused on the impact of infection with the tobacco mosaic virus (TMV). Specifically, changes in phytochemicals and gene activity related to pathogenesis-related and phenylpropanoid pathway genes in tomato plants (Solanum lycopersicum L.) during a period of 2–14 days post-inoculation (dpi). According to TEM investigation and coat protein sequence analysis, the purified TMV Egyptian AM isolate (PP133743) has a rod-shaped structure with a diameter of around 110 nm. The RT-qPCR analysis revealed that PR-1 showed an initial increase after TMV infection, as seen in the time-course analysis. In contrast, PR-2 was consistently elevated throughout the infection, suggesting a stronger reaction to the virus and suppressing PAL expression at 6 to 14 dpi. The expression levels of HQT and CHS transcripts exhibited alternating patterns of up-regulation and down-regulation at different time intervals. The HPLC and GC–MS analysis of control- and TMV-infected tomato extracts revealed that different phenolic, flavonoid, and fatty acid compounds were increased (such as naringenin, rutin, flavone, ferulic acid, and pyrogallol) or significantly decreased (such as salicylic acid and chlorogenic acid) after TMV infection. The ability of TMV to inhibit most polyphenolic compounds could potentially accelerate the viral life cycle. Consequently, focusing on enhancing the levels of such suppressed compounds may be critical for developing plant viral infection management strategies.

Green biocatalytic synthesis of (hydroxy)cinnamic monoterpenyl esters in biomass solvent: Mechanism underlying different reaction efficiency

(Hydroxy)cinnamic acids (HCAs), a kind of prevalent phenolic acid compound, boast diverse biological activities. However, their limited liposolubility impedes their utilization in oil-based systems. Addressing this challenge, we presented an eco-friendly approach to synthesize (hydroxy)cinnamic monoterpenyl esters in biomass solvent 2-methyltetrahydrofuran (2-MeTHF), grafting antibacterially active monoterpenyl onto phenolic acid compounds through esterification/transesterification. This green enzymatic catalytic strategy successfully synthesized a series of cinnamic monoterpenyl esters (yield >87.84%), p-coumaric monoterpenyl esters (yield >67.26%), and caffeic monoterpenyl esters (yield >10.55%). The mechanism difference in reaction efficiency of different hydroxyl cinnamic acids was revealed through kinetic calculation and molecular docking. As the number of hydroxyl group increased, the affinity between substrates and lipase decreased, which was reflected by the Km value, in which the Km value of cinnamic acid, p-coumaric acid and caffeic acid were 23.72, 52.04 and 60.05, respectively. Furthermore, molecular docking results showed that the strong binding of the hydroxyl groups to the hydrophobic cavity of the lipase resulted in the need for more energy to twist the reaction site closer to the active center during the reaction. This research provided a green and feasible route for the synthesis of phenolic acid ester derivatives.

Joint metabolomic and transcriptomic analysis identify unique phenolic acid and flavonoid compounds associated with resistance to fusarium wilt in cucumber (Cucumis sativus L.).

Fusarium wilt (FW) caused by Fusarium oxysporum f. sp. cucumerinum (Foc) is a destructive soil-borne disease in cucumber (Cucumis sativus. L). However, there remains limited knowledge on the molecular mechanisms underlying FW resistance-mediated defense responses in cucumber. In this study, metabolome and transcriptome profiling were carried out for two FW resistant (NR) and susceptible (NS), near isogenic lines (NILs) before and after Foc inoculation. NILs have shown consistent and stable resistance in multiple resistance tests conducted in the greenhouse and in the laboratory. A widely targeted metabolomic analysis identified differentially accumulated metabolites (DAMs) with significantly greater NR accumulation in response to Foc infection, including many phenolic acid and flavonoid compounds from the flavonoid biosynthesis pathway. Transcriptome analysis identified differentially expressed genes (DEGs) between the NILs upon Foc inoculation including genes for secondary metabolite biosynthesis and transcription factor genes regulating the flavonoid biosynthesis pathway. Joint analysis of the metabolomic and transcriptomic data identified DAMs and DEGs closely associated with the biosynthesis of phenolic acid and flavonoid DAMs. The association of these compounds with NR-conferred FW resistance was exemplified by in vivo assays. These assays found two phenolic acid compounds, bis (2-ethylhexyl) phthalate and diisooctyl phthalate, as well as the flavonoid compound gallocatechin 3-O-gallate to have significant inhibitory effects on Foc growth. The antifungal effects of these three compounds represent a novel finding. Therefore, phenolic acids and flavonoids play important roles in NR mediated FW resistance breeding in cucumber.

Phenolic Acid-β-Cyclodextrin Complexation Study to Mask Bitterness in Wheat Bran: A Machine Learning-Based QSAR Study.

The need to solvate and encapsulate hydro-sensitive molecules drives noticeable trends in the applications of cyclodextrins in the pharmaceutical industry, in foods, polymers, materials, and in agricultural science. Among them, β-cyclodextrin is one of the most used for the entrapment of phenolic acid compounds to mask the bitterness of wheat bran. In this regard, there is still a need for good data and especially for a robust predictive model that assesses the bitterness masking capabilities of β-cyclodextrin for various phenolic compounds. This study uses a dataset of 20 phenolic acids docked into the β-cyclodextrin cavity to generate three different binding constants. The data from the docking study were combined with topological, topographical, and quantum-chemical features from the ligands in a machine learning-based structure-activity relationship study. Three different models for each binding constant were computed using a combination of the genetic algorithm (GA) and multiple linear regression (MLR) approaches. The developed ML/QSAR models showed a very good performance, with high predictive ability and correlation coefficients of 0.969 and 0.984 for the training and test sets, respectively. The models revealed several factors responsible for binding with cyclodextrin, showing positive contributions toward the binding affinity values, including such features as the presence of six-membered rings in the molecule, branching, electronegativity values, and polar surface area.

Plant hormones and phenolic acids response to UV-B stress in Rhododendron chrysanthum pall

Our study aims to identify the mechanisms involved in regulating the response of Rhodoendron Chrysanthum Pall. (R.chrysanthum) leaves to UV-B exposure; phosphorylated proteomics and metabolomics for phenolic acids and plant hormones were integrated in this study. The results showed that UV-B stress resulted in the accumulation of salicylic acid and the decrease of auxin, jasmonic acid, abscisic acid, cytokinin and gibberellin in R.chrysanthum. The phosphorylated proteins that changed in plant hormone signal transduction pathway and phenolic acid biosynthesis pathway were screened by comprehensive metabonomics and phosphorylated proteomics. In order to construct the regulatory network of R.chrysanthum leaves under UV-B stress, the relationship between plant hormones and phenolic acid compounds was analyzed. It provides a rationale for elucidating the molecular mechanisms of radiation tolerance in plants.

Physiological and molecular mechanism of Populus pseudo-cathayana × Populus deltoides response to Hyphantria cunea

Populus pseudo-cathayana × Populus deltoides is a crucial artificial forest tree species in Northeast China. The presence of the fall webworm (Hyphantria cunea) poses a significant threat to these poplar trees, causing substantial economic and ecological damage. This study conducted an insect-feeding experiment with fall webworm on P. pseudo-cathayana × P. deltoides, examining poplar's physiological indicators, transcriptome, and metabolome under different lengths of feeding times. Results revealed significant differences in phenylalanine ammonia-lyase activity, total phenolic content, and flavonoids at different feeding durations. Transcriptomic analysis identified numerous differentially expressed genes, including AP2/ERF, MYB, and WRKY transcription factor families exhibiting the highest expression variations. Differential metabolite analysis highlighted flavonoids and phenolic acid compounds of poplar's leaves as the most abundant in our insect-feeding experiment. Enrichment analysis revealed significant enrichment in the plant hormone signal transduction and flavonoid biosynthetic pathways. The contents of jasmonic acid and jasmonoyl-L-isoleucine increased with prolonged fall webworm feeding. Furthermore, the accumulation of dihydrokaempferol, catechin, kaempferol, and naringenin in the flavonoid biosynthesis pathway varied significantly among different samples, suggesting their crucial role in response to pest infestation. These findings provide novel insights into how poplar responds to fall webworm infestation.

Transcriptomic analysis reveals candidate genes for phenolic acid biosynthesis in Polygonum chinense L.

Polygonum chinense L. (synonym: Persicaria chinensis) was considered a medicinal food homology plant, which was often used in herbal tea. This plant is rich in phenolic acid compounds that possess antibacterial, antioxidant, and other pharmacological properties. Although phenolic acids of P. chinense have been investigated pharmacologically, the genetic basis of phenolic acid biosynthesis in this plant is unknown due to the lack of a reference genome. In this study, we employed a combination of transcriptomics and bioinformatic analysis to construct a transcriptome database for three tissues (flowers, leaves, and stems) of P. chinense, and extracted genes related to the biosynthesis of phenolic acids. In total, 90,635 unigenes with a mean length of 1224 bp were obtained, 70,915 of which were functionally annotated. Seventy-eight differentially expressed genes (DEGs) associated with the phenolic acid biosynthetic pathway were identified, with five DEGs (CL4812–1, CL7291–1, CL5600–1, CL6332–3, and Unigene12384) being singled out as candidate genes putatively involved in the regulation of phenolic acid biosynthesis through correlation analysis. A comprehensive sequence analysis of these candidate genes was subsequently performed. The phylogenetic tree and the structural model were constructed, and molecular docking studies were conducted for the 4-coumarate-CoA ligase. Additionally, the expression levels of 12 unigenes encoding key enzymes involved in phenolic acid biosynthesis were validated using quantitative reverse transcription-PCR. Our study provides candidate genes at the transcriptional level for further investigation of the molecular regulatory mechanisms involved in phenolic acid biosynthesis, as well as a scientific basis for the development of P. chinense as a food-medicine dual-purpose plant.

Uncovering Chemical Interactions between Danshen and Danggui Using Liquid Chromatography–Mass Spectrometry and Network Pharmacology-Based Research on Stroke

Abstract Objective: The objective of this study was to decipher chemical interactions between Danshen and Danggui using liquid chromatography–mass spectrometry (LC-MS) and explore the mechanisms of Danshen–Danggui against stroke using network pharmacology and molecular docking. Materials and Methods: First, the chemical compounds of Danshen–Danggui were profiled using ultra-high-performance liquid chromatography (HPLC)-quadrupole time-of-flight MS. Accurately characterized compounds in various proportions of Danshen–Danggui were quantified using HPLC combined with triple quadrupole electrospray tandem MS. Network pharmacology was used to uncover the essential mechanisms of action of Danshen–Danggui against stroke. Discovery Studio Software was used for the molecular docking verification of key active chemicals and stroke-related targets. Results: A total of 53 compounds were characterized, and 22 accurately identified constituents (10 phenolic acids, 8 phthalides, and 4 tanshinones) were quantified in 15 proportions of Danshen–Danggui. The quantification results showed that Danggui significantly increased the dissolution of most phenolic acids (compounds from Danshen), whereas Danshen promoted the dissolution of most phthalides (compounds from Danggui). Overall, the combination of Danshen and Danggui at a 1:1 ratio resulted in the maximum total dissolution rate. Further network pharmacology and molecular docking results indicated that Danshen–Danggui exerted anti-stroke effects mainly by regulating inflammation-related (tumor necrosis factor, hypoxia-inducible factor, and toll-like receptor) signaling pathways, which ranked among the top three pathways based on Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Conclusion: The chemical compounds in Danshen–Danggui could interact with each other to increase the dissolution of the most active compounds, which could provide a solid basis for uncovering the compatibility mechanisms of Danshen–Danggui and Danshen–Danggui-based formulae.

Microwave hydrodistillation of Pelargonium graveolens L’Her leaves: Essential oil profile, phytochemical composition of wastewater, histo-anatomical structure

By-products with remarkable bioactive properties are formed in extraction processes of essential oils from plant materials. In present study, it was aimed to determine the concentration of individual phenolic and organic acid compounds by LC-MS/MS of the by-product (wastewater) collected after the essential oil isolation from Pelargonium graveolens L. and to determine some bioactive properties of this by-product. In addition, the chemical analysis and antibacterial activity of the essential oil extracted from P. graveolens were determined and the histo-anatomical characterization of the glandular trichomes in the leaf sample was performed. As a result, quercetin (95862.22 μg/kg), myricetin (59834.32 μg/kg) and rutin (36522.90 μg/kg) were the phenolic compounds determined in the highest concentrations in the by-product extracted using two different extraction techniques (non-hydrolysis and hydrolysis methods). Moreover, the individual organic acids of the by-product screened in LC-MS/MS was found to be 4487.17 mg/kg in total. When the essential oil component profile of the plant sample was examined, the citronellol (38.78%) compound was found to be dominant, and it was also detected that the essential oil had remarkable bioactive properties. In conclusion, it can be stated that both the essential oil obtained from P. graveolens and the by-product obtained during essential oil isolation can be considered as a source of some bioactive components in many different industrial applications.

Development of a co-culture system for green production of caffeic acid from sugarcane bagasse hydrolysate.

Caffeic acid (CA) is a phenolic acid compound widely used in pharmaceutical and food applications. However, the efficient synthesis of CA is usually limited by the resources of individual microbial platforms. Here, a cross-kingdom microbial consortium was developed to synthesize CA from sugarcane bagasse hydrolysate using Escherichia coli and Candida glycerinogenes as chassis. In the upstream E. coli module, shikimate accumulation was improved by intensifying the shikimate synthesis pathway and blocking shikimate metabolism to provide precursors for the downstream CA synthesis module. In the downstream C. glycerinogenes module, conversion of p-coumaric acid to CA was improved by increasing the supply of the cytoplasmic cofactor FAD(H2). Further, overexpression of ABC transporter-related genes promoted efflux of CA and enhanced strain resistance to CA, significantly increasing CA titer from 103.8 mg/L to 346.5 mg/L. Subsequently, optimization of the inoculation ratio of strains SA-Ec4 and CA-Cg27 in this cross-kingdom microbial consortium resulted in an increase in CA titer to 871.9 mg/L, which was 151.6% higher compared to the monoculture strain CA-Cg27. Ultimately, 2311.6 and 1943.2 mg/L of CA were obtained by optimization of the co-culture system in a 5 L bioreactor using mixed sugar and sugarcane bagasse hydrolysate, respectively, with 17.2-fold and 14.6-fold enhancement compared to the starting strain. The cross-kingdom microbial consortium developed in this study provides a reference for the production of other aromatic compounds from inexpensive raw materials.

Effectiveness of Cyclic Voltammetry in Evaluation of the Synergistic Effect of Phenolic and Amino Acids Compounds on Antioxidant Activity: Optimization of Electrochemical Parameters.

Antioxidant activity can be evaluated using cyclic voltammetry (CV). The aim of this work is to verify the efficacy of CV in evaluating the synergistic effect of bioactive compounds, such as phenolic and amino acid compounds, on antioxidant activity. Therefore, three types of model solutions were prepared: individual model solution (phenol and amino acid), (b) binary model solutions (phenol-phenol and amino acid-amino acid) and (c) mixed phenol-amino acid solutions. Electrochemical measurement conditions were optimized for phenolic compounds (pH 3.0, 1.0 g/L and 100 mV/s) and for amino acids (pH 7.0, 2.0 g/L for amino acids and 100 mV/s), and, for each solution, the functional groups responsible of the anodic and cathodic peaks were established. The peak anodic potential (Epa) and the onset potential (Eon) were two parameters of great importance. The first one was used to classify the solutions according to their antioxidant potential. In general, all the binary and mixed solutions had lower values of Epa than the corresponding individual model solution, which indicates an improvement in the antioxidant potential. The second one was used to evaluate the synergistic effects of phenolic compounds and amino acids.

Isolation of Phenolic Acids from Land Kale (Ipomoea reptans Poir) and Antioxidant Activity

Land kale or Ipomoea reptans Poir is widely consumed by Indonesian people. Land kale plants can be used as natural antioxidants because they contain polyphenolic compounds, one of which is phenolic acid. This research was carried out to determine the antioxidant activity and isolate phenolic acid compounds contained in land kale plants (Ipomoea reptans Poir). The sample used was an ethanol extract of land kale. The total phenolics were determined using the Folin-Ciocalteu method. Phenolic acids were isolated using alkaline hydrolysis and acid hydrolysis and without hydrolysis methods. Separation of isolates was carried out using the TLC method. The structure was identified using UV-Vis spectrophotometry and LC-MS/MS. Antioxidant activity was measured using the DPPH method. The total phenolics of land kale ethanol extract were 71.2420 ± 0.0791 mg/g GAE. TLC showed that the HB, HA, and TH fractions contained caffeic acid and ferulic acid compounds. Separation of the (HB) fraction produced three isolates: B2 with a yellow color, B3 with a slightly yellowish color, and B4 which is colorless. Isolate B2 was identified as potentially containing caffeic acid, while isolate B3 was indicated to potentially contain ferulic acid through analysis using a UV-Vis spectrophotometer. Isolate B4 was thought to have a hydroxybenzoic acid framework after being determined using LC-MS/MS. The ethanol extract of land kale has strong antioxidant activity because it produces an IC50 value of 94.83 mg/L.