Search Results (1,371)

Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the vertebrate central nervous system, known for its role in promoting sleep, reducing anxiety, regulating blood pressure, and modulating stress, cognition, and behavior. Microbial fermentation offers an effective method for GABA production, with certain lactic acid bacteria (LAB) strains recognized as efficient producers. This study assessed the GABA-producing potential of 31 LAB strains, including isolates from traditional Bulgarian foods and plants. The strains were cultivated in an MRS medium supplemented with 1% monosodium glutamate (MSG), and GABA production was quantified using HPLC after derivatization with dansyl chloride. Most strains produced between 200 and 300 mg/L of GABA. However, Levilactobacillus brevis NCTC 13768 showed much higher productivity, reaching 3830.7 mg/L. To further evaluate its capacity, L. brevis NCTC 13768 was cultivated for 168 h in MRS medium with and without MSG. Without MSG, GABA production peaked at 371.0 mg/L during the late exponential phase. In contrast with MSG, GABA levels steadily increased, reaching 3333.6 mg/L after 168 h. RT-qPCR analyses of the glutamic acid decarboxylase (GAD) system showed that the genes of glutamate decarboxylase (gadB), glutamate-GABA antiporter (gadC), and transcriptional regulator (gadR) are significantly overexpressed when the culture reaches the late stationary phase of growth (96 h after the beginning of cultivation). These results identify L. brevis NCTC 13768 as a high-yield GABA producer, with potential applications in the production of fermented functional foods and beverages. Full article

Fermented fruit juices are considered functional beverages because they contain bioactive compounds derived from plant materials and produced by the microorganisms involved in fermentation. The composition of these beverages can vary depending on the strain used. This study aimed to determine the effect of different microorganisms conducting lactic acid fermentation on the chemical composition and bioactive component content of naturally cloudy fermented pear and plum juices. The process used Lactiplantibacillus plantarum K7 bacteria, which were isolated during sauerkraut fermentation, as well as Lachancea thermotolerans PYCC6375 and Lachancea fermentati PYCC5883 yeast cultures, which have poor ethanol fermentation capabilities. The pH, acidity, sugars (HPLC), free amino nitrogen, selected organic acids (HPLC), color (CIELAB), polyphenols (HPLC), volatiles (GC-MS), aroma-active volatiles (GC-MS-O), and sensory characteristics were analyzed. The fermented juices obtained were rich in organic acids (of plant and microbial origin), polyphenols, and had a reduced sugar content (with polyols replacing glucose and fructose), as well as a low alcohol content (<0.2%). At the same time, all three microorganisms significantly enhanced the fruity aroma of the juices. Lachancea yeasts proved to be a viable alternative to lactic acid bacteria for producing fermented juices and were significantly better suited to fermenting plum juices. The highest polyphenol content and highest consumer preference rating were obtained with plum juices fermented with L. fermentati yeast. Full article

Natural resins are complex mixtures of secondary metabolites produced by many plants in response to stress or injury and have long been used for their antimicrobial, anti-inflammatory, and antioxidant properties. Among resin-producing genera, Commiphora Jacq. (Burseraceae) stands out for the traditional and medicinal relevance of its oleogum resins, commonly known as myrrh. In this study, we investigated, for the first time, the non-volatile fraction of the oleogum resin of Commiphora ornifolia (Balf.f.) J.B.Gillett, which is an endemic species of Socotra Island. Ethanol extraction followed by chromatographic and spectroscopic analysis (HPLC-DAD, NMR, HRMS) led to the isolation of (+)-yangambin, a furofuran lignan not previously reported in this species. Quantitative analysis showed yangambin to be present in all eight resin samples analyzed, at concentrations ranging from 3.50 (±0.02) to 9.05% (±0.19) of the ethanol extract. In addition, the analysis of the hydrolyzed polysaccharide fraction revealed the presence of arabinose, rhamnose, galactose, and galacturonic acid. These preliminary findings highlight the phytochemical richness of C. ornifolia oleogum resin and suggest the presence of other potentially bioactive compounds. The presence of yangambin, known for various pharmacological activities, supports further phytochemical and biological studies on this largely unexplored species. Full article

Tetrahydroprotoberberine alkaloids (THPBs) are bioactive natural products bearing stereogenic centers that frequently exhibit enantiomer-specific pharmacological effects. Xylopinine (XPN), a representative THPB, shows cytotoxic, antimicrobial, and antimalarial activity in vitro, and displays pronounced stereoselectivity in vivo, with the naturally occurring (S)-enantiomer emphasizing the need for reliable enantioselective analysis. In this study, we present the synthesis of racemic XPN from norlaudanosine, and its first comprehensive cyclodextrin-assisted capillary electrophoresis screening dedicated to the enantioseparation of XPN. Sulfated- and sulfobutyl-ether-β-cyclodextrin (S-β-CyD, SBE-β-CyD) provided efficient resolution (R_s > 3), while heptakis-(6-deoxy-6-(2-carboxyethyl)thio)-β-CyD (subetadex, SBX) yielded outstanding separation (R_s > 9). The enantiomer migration order was consistently R,S, except when using SBE-β-CyD, which showed the inverse sequence. Chiral HPLC using a Chiralpak AD column in polar organic mode with methanol modified with 0.1% diethylamine as mobile phase enabled the semi-preparative isolation of XPN enantiomers, with the (S)-enantiomer exceeding 95% purity. The absolute configuration was confirmed by circular dichroism spectroscopy. ¹H NMR titration and 2D rotating-frame nuclear Overhauser effect correlation spectroscopy (ROESY) consistently revealed multi-site recognition of XPN by SBX, supporting the inclusion of both aromatic rings (A and D). Full article

Echinacea purpurea (L.) Moench root is a rich source of alkamides and other bioactive compounds with potential health-promoting effects. This study aimed to evaluate the influence of drying technique and carrier type on alkamide content, antioxidant properties, and process contaminants in E. purpurea powders. Root extracts were subjected to freeze-drying or spray drying at air inlet temperatures of 150, 170, and 190 °C, with maltodextrin, pea protein isolate, or their blend used as carrier agents. The resulting powders were analyzed for physical and chemical properties, including alkamides concentration, total phenolics content, antioxidant capacity, free amino group levels, and markers of advanced Maillard reaction products. Spray-dried powders had a moisture content lower than 2.3%, compared with an average of 7.7% in freeze-dried samples. Spray drying at 150 and 170 °C combined with the maltodextrin–pea protein blend resulted in the highest alkamide levels, while total phenolics content and antioxidant capacity were retained at levels comparable to freeze-drying. Neither hydroxymethyl-L-furfural nor furfural was detected via HPLC in any sample. Overall, spray drying under the tested conditions represents a favorable alternative to freeze drying, yielding E. purpurea root extracts powders with higher alkamides content, similar antioxidant properties, and absence of process contaminants. Full article

Infusions of the leaves of Ribes magellanicum (Grossulariaceae) are used as a digestive in southernmost South America. This work aimed to assess the composition and activity of infusions and MeOH:H₂O 7:3 extracts of R. magellanicum leaves on enzymes related to metabolic syndrome (α-glucosidase, α-amylase, and pancreatic lipase), as well as their antioxidant capacity. Samples from a longitudinal gradient from central southern Chile to the islands in the Beagle Channel were investigated. Lyophilized infusions and extracts were used for all determinations, including inhibition of the selected enzymes, total phenolic (TP), total flavonoid (TF), total procyanidins (TPC), and antioxidant capacity (DPPH, FRAP, TEAC, and ORAC). The composition of the samples was assessed by HPLC-DAD. Some 99 compounds were tentatively identified by HPLC-MSⁿ. The main phenolics were quantified using calibration curves with reference compounds. Relevant differences exist in the ratio of constituents in infusions compared to hydroalcoholic extracts. The samples were inactive towards α-amylase and pancreatic lipase at 100 and 50 µg/mL, respectively. Assay-guided isolation of α-glucosidase inhibitors led to fractions with high activity (IC₅₀: 0.02–0.05 µg/mL). The strong inhibition of α-glucosidase and antioxidant capacity of the infusion and extracts of R. magellanicum leaves support its traditional use in southern Patagonia. Full article

Marshmallows are confectioneries that are popular among children and teenagers around the world. Barbecues and the consumption of grilled marshmallows, especially by children, have become fashionable in many countries. Grilled marshmallows may contain carcinogenic polycyclic aromatic hydrocarbons (PAHs). Hydroxy-PAHs (OH-PAHs) concentration in the urine of volunteers after the consumption of grilled marshmallows, as biomarkers of exposure to PAHs, have been determined. A total of 24 participants consumed marshmallows grilled under similar conditions. Urine samples were collected before and after the consumption of grilled marshmallows. 1-hydroxypyrene and 9-hydroxyphenanthrene concentrations in urine samples were determined using the HPLC-FLD technique after enzymatic hydrolysis and isolation by solid-phase extraction (SPE). The average concentration of 1-hydroxypyrene was 0.21 ± 0.16 µg/g creatinine and of 9-hydroxypenanthrene was 2.78 ± 2.55 µg/g creatinine. The concentrations of OH-PAHs in the urine of volunteers eating colored grilled marshmallows were higher compared to the consumption of white ones. In the case of 9-hydroxyphenanthrene this difference was statistically significant p < 0.05. Grilled marshmallows constitute a source of exposure to PAHs, especially in the group of children and adolescents. Even consumption of small or moderate amounts of grilled marshmallows resulted in a significant increase in concentrations of PAH metabolites in the urine compared to the level of these compounds before the intake. Full article

Although sulfonated acridines and acridones are valuable scaffolds in diagnostics and materials science, to our best knowledge, there is no comprehensive study that addresses how the degree of sulfonation depends on reaction parameters. To fill this gap, we investigated the sulfonation behavior of unsubstituted acridine and acridone under classical conditions, using sulfuric acid, oleum, and chlorosulfonic acid. A factorial experimental design was applied to systematically evaluate the influence of temperature and reagent excess on the extent of sulfonation, while keeping the reaction time constant. Products were analyzed by HPLC–MS/MS to determine the degree of sulfonation and its distribution. Regioselectivity and product isolation were not addressed in this study. Our results provide a foundational dataset for controlling sulfonation level for these heterocycles and can help future synthetic applications where defined sulfonation patterns are desired. Full article

The palo prieto (Lysiloma divaricata) is a tree with grayish bark and pinnate leaves that is native to Mexico. This tree can reach heights close to 15 m and is a source of phytochemical compounds, including polyphenols. The optimized extraction method is important for preserving phytochemical compounds, particularly gallic acid. In general, solid-liquid extraction methods are the most commonly used methods for obtaining phytochemical compounds from Lysiloma divaricata. Herein, we report the results of a complex experimental design in which different parts of the plant (leaf, stem, and fruit) were used to investigate their antioxidant activities and gallic acid contents. In this design, we included variations in the type of solvent, time, and temperature. This method yields an extract rich in phytochemical components that may exhibit significant antioxidant activity, making it suitable for isolating natural antioxidant compounds. For these compounds, bromatological analysis, quantification of phenolic content, and identification and quantification of phytochemical compounds via UPLC-MS/MS identified 27 compounds, with gallic epicatechin, catechin, kaemferol-3-glucoside, procyanidin B1, and gallic acid as the major compounds. For the quantification of gallic acid by HPLC, the highest concentration of gallic acid was detected in the water-leaf-40 °C-90 min fraction. In addition, antioxidant activity via 1,1-diphenyl-1,2-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) was studied, and color measurements were performed. Additionally, the antioxidant activity of the fruit samples was evaluated via the DPPH method with an ethanol/water ratio of 30:70 % v/v at 60 °C for 60 min, which resulted in the highest percentage of inhibition. There was no significant difference in the antioxidant activity when ABTS was used between the samples. For the antioxidant activity determined via FRAP, the leaf sample exhibited the most significant activity when ethanol was used as the solvent at 50 °C for 90 min, with a value of 195,861 ± 44.20 µM eq Trolox/g DM. The phenol compounds of Lysiloma divaricata are promising sources of natural antimicrobials and antioxidants for potential applications in food packaging. Full article

Protaetia brevitarsis seulensis (Kolbe, 1886) larvae have traditionally been used in East Asian medicine and have recently attracted attention as functional food ingredients because of their pharmacological potential. However, chemical investigations remain limited, and no marker compounds have been established for quality control. This study aimed to isolate and identify a primary constituent from the 70% ethanol extract of P. brevitarsis (PBE) and to develop an analytical method for its quantification. Among the solvent-partitioned fractions, the n-butanol fraction (PBE-B) exhibited a major peak in HPLC analysis. The compound was purified through a combination of vacuum liquid chromatography (VLC), medium-pressure liquid chromatography (MPLC), and recycling preparative HPLC. Its structure was identified as L-tryptophan based on HR-ESI-MS and NMR spectroscopy. Quantitative analysis was conducted using HPLC-DAD under optimized analytical conditions, employing a Thermo Scientific™ Acclaim™ Polar Advantage II column and an acidified mobile phase (0.1% formic acid in water and methanol) to improve resolution. The method demonstrated excellent linearity (r² > 0.9999), and the L-tryptophan content in PBE was determined to be 1.93 ± 0.05 μg/mg. The analyte was well separated with minimal interference, supporting the reproducibility of the method. These results indicate that L-tryptophan is a promising candidate Q-marker for the quality control of P. brevitarsis extracts. Full article

Lactiplantibacillus pentosus is a lactic acid bacterium frequently detected in various fermented foods; however, the genomic traits related to its biotechnological potential have been underexplored. In this study, 34 catalase-negative isolates were obtained from pickled mustard greens, among which strain P7 exhibited the highest exopolysaccharide (EPS) yield (781.9 ± 14.7 mg/L) and was capable of growing in a chemically defined medium lacking riboflavin. Whole-genome sequencing revealed a 3,749,478 bp circular chromosome with 46.5% G + C content and 3389 protein-coding genes. A phylogenomic analysis identified P7 as L. pentosus. Functionally, 1 mg/mL EPS extracted from P7 demonstrated strong antioxidant activity, with DPPH and hydroxyl radical scavenging capacities of 89.8 ± 4.6% and 76.5 ± 9.5%, respectively. The use of 0.2 mg/mL EPS also protected Saccharomyces cerevisiae cells from oxidative stress. A comparative genomic analysis indicated the presence of nearly complete biosynthetic pathways for riboflavin, folate, and pyridoxine. High-performance liquid chromatography (HPLC) confirmed the production of 23.8 ± 0.4 µg/mL riboflavin, 36.6 ± 0.6 µg/mL folic acid, and 0.42 ± 0.02 µg/mL pyridoxine in the culture supernatant, which have not been previously reported. Additionally, strain P7 produced 91.2 ± 12.3 g/L of lactic acid after 24 h of incubation. These results support the potential of L. pentosus P7 as a candidate for industrial applications in the production of EPS, B-group vitamins, and lactic acid. Full article

Plants of the genus Porophyllum (Asteraceae) have traditional medicinal uses, but only 8 of 25 species have been studied. This study aimed to profile volatile compounds, phenolics, and fatty acids in dried leaves and stems of Porophyllum gracile and assess biological activities of extracts obtained using different solvents. GC-MS, HPLC-DAD, and GC-FID analyses identified over 120 compounds, including fatty acids, chlorogenic acid derivatives, quercetin derivatives, terpenes, ketones, aldehydes, and alcohols. Antioxidant activity in vitro (ABTS, DPPH, and FRAP assays) suggested a strong electron-transfer-mediated mechanism. In ARPE-19 cells under doxorubicin-induced oxidative stress, hexane and ethanolic extracts from leaves and stems significantly reduced intracellular reactive oxygen species, in some cases outperforming vitamin E. No antiproliferative activity was detected against cancer cell lines (MDA-MB-231, HeLa, A549, HCT 116, 22Rv1), nor cytotoxicity toward non-cancerous cells (ARPE-19, hFOB 1.19). This first detailed phytochemical characterization of P. gracile demonstrates its cellular antioxidant potential and supports its application as a natural antioxidant source in functional foods or nutraceuticals. Future work should elucidate mechanisms, isolate active compounds, and evaluate bioavailability in in vivo models. Full article

Heliotropium procumbens, a Boraginaceae species native to Panama, has remained largely unexplored regarding its nitrogen-containing metabolites, including pyrrolizidine alkaloids (PAs). In the current study, a comprehensive phytochemical investigation of its aerial parts is presented using HPLC-DAD-IT-MS, UHPLC–HRMS, and GC-MS primarily to profile its PA composition. A total of twelve PAs and N-oxides (PANOs) were identified, along with two phenolamides—including N¹, N¹⁰-diferuloylspermidine, which is biosynthetically related to PAs—and the distinctive metabolite heliotropamide. The detected PAs included unsaturated necines, primarily monoesters of retronecine and heliotridine, as well as saturated PAs such as a platynecine-type PA and the less commonly encountered triol necines and their N-oxides. Among these, helifoline-N-oxide was isolated and structurally elucidated by NMR spectroscopy for the first time as a natural product. Comparison with the chemodiversity of PAs within the Heliotropium genus revealed a high degree of diversity in H. procumbens, which can be attributed both to the species’ inherent biosynthetic capacity for chemical variation and to the more comprehensive and extensive studies conducted on it, which naturally enrich the apparent diversity observed. This work expands the phytochemical knowledge of H. procumbens and contributes to a broader understanding of PA diversity in the genus, offering new insights into their potential ecological and toxicological significance. Full article

Lopezia racemosa Cav., commonly known as “cancer herb” in indigenous communities, has long been used for its medicinal properties. The biotechnological production of its bioactive compounds through genetic transformation represents a valuable approach for obtaining pharmacologically relevant substances. The initial focus of this study was to identify compounds previously reported in the species; however, phytochemical analysis by HPLC and NMR led to the isolation and identification of two pentacyclic triterpene esters not previously described in L. racemosa: 3-O-[(E)-feruloyl]-maslinic acid (1) and 3-O-[(E)-feruloyl]-corosolic acid (2), identified as constituents of fraction 33. The LRTC3.1 callus line was obtained from hairy roots generated by infecting L. racemosa leaf explants with Agrobacterium rhizogenes strain ATCC15834/pTDT. The crude extract, specific fractions, and the mixture of these compounds demonstrated significant anti-inflammatory and cytotoxic activities. Anti-inflammatory activity was evaluated using the carrageenan-induced mouse paw edema model, where the crude extract achieved 51.02% inhibition of inflammation compared to meloxicam (30.86%). Cytotoxicity was assessed against three human cancer cell lines: breast carcinoma (MCF7), cervical carcinoma (SiHa), and colon carcinoma (HCT-15). Fractions FD (28–29) and 33 exhibited potent cytotoxic effects, with IC₅₀ values of 0.508 and 1.345 µg/mL against SiHa cells, and 0.053 and 2.693 µg/mL against MCF-7 cells, respectively. These findings suggest that transformed L. racemosa cultures represent a promising source of bioactive compounds for potential therapeutic development. Full article

Adenosine deaminase (ADA) is one of the most important enzymes in nucleoside metabolism, regulating the levels of adenosine and deoxyadenosine triphosphate (ADT/dATP) on either side of the cell membrane. This small protein (weighing approximately 40 kDa) exhibits deamination properties towards other pharmaceuticals built on adenine as the leading structure, which requires co-administration of ADA inhibitors. 3′-deoxyadenosine (Cordycepin, Cord) is an active compound isolated from the fungus Cordyceps, which has been used in traditional Chinese medicine for over 2000 years. Its anticancer activity is likely related to the inhibition of primer elongation of lagging strands during genetic information replication. Unfortunately, Cord is rapidly deaminated by ADA into inactive 3′-deoxyinosine, necessitating its co-administration with ADA inhibitors. Here, for the first time, the synthesis and discussion of the oxidised form of Cord are presented. The 7,8-dihydro-8-oxo-3′-deoxyadenosine (Cord^OXO) exhibits high resistance to ADA because of its syn conformation, as shown experimentally by UV spectroscopy and RP-HPLC monitoring. Theoretical Density Functional based Tight Binding (DFTB) studies of the Michaelis complex ADA-Cord^OXO have revealed significant distance increases between the “active” H₂O molecule and C6 of the 8-oxo-adenine moiety of Cord^OXO, i.e., 4 Å as opposed to 2.7 Å in the cases of ADA-dAdo and Cord. In conclusion, it can be postulated that the conversion of Cord to Cord^OXO enhances its therapeutic potential; however, this needs to be verified in vitro and in vivo. It should be emphasised that the therapeutic effect, if any, can be achieved theoretically without ADA inhibitors, e.g., pentostatin, thus reducing adverse effects. These promising preliminary results, presented here, warrant further investigations. Full article