The Nicotiana tabacum UGT89A2 enzyme catalyzes the glycosylation of di- and trihydroxylated benzoic acid derivatives.

Glycosyltransferases catalyze the transfer of a glycoside group to a wide range of acceptor compounds to produce glycoconjugates with diverse biological and pharmacological activities. The present work reports the identification and biochemical characterization of Nicotiana tabacum UGT89A2 glycosyltransferase (NtUGT89A2). The enzyme is a monomer in solution that catalyzes the O-ß-glucosylation of di- and tri-hydroxylated and chlorinated derivatives of benzoic acid. NtUGT89A2 has a preference for 2,5-dihydroxybenzoic acid (2,5-DHBA) over 2,3-dihydroxybenzoic acid (2,3-DHBA) and 2,4-dihydroxybenzoic acid (2,4-DHBA). Other substrates that can be used by NtUGT89A2 include 3,4,5-trihydroxybenzoic acid and chlorinated derivatives such as 2-chloro-5-hydroxybenzoic acid (2-Cl-5-HBA). The substrates of NtUGT89A2 were identified by thermal stability experiments, where we observed a maximum increase of the thermal denaturation midpoint (Tm) of 10 °C in the presence of 2,5-DHBA and UDP-glucose. On the other hand, the highest specific activity was obtained with 2,5-DHBA (225 ± 1.7 nkat/mg). Further characterization revealed that the enzyme has a micromolar affinity for its substrates. Notably, the enzyme retains full activity after incubation at 70 °C for 1 h. These results provide a basis for future functional and structural studies of NtUGT89A2.

Fragile Treg cells: Traitors in immune homeostasis?

Regulatory T (Treg) cells play a key role in maintaining immune tolerance and tissue homeostasis. However, in some disease microenvironments, Treg cells exhibit fragility, which manifests as preserved FoxP3 expression accompanied by inflammation and loss of immunosuppression. Fragile Treg cells are formatively, phenotypically and functionally diverse in various diseases, further complicating the role of Treg cells in the immunotherapeutic response and offering novel targets for disease treatment by modulating specific Treg subsets. In this review, we summarize findings on fragile Treg cells to provide a framework for characterizing the formation and role of fragile Treg cells in different diseases, and we discuss how this information may guide the development of more specific Treg-targeted immunotherapies.

Potential mechanism of gallic acid-coated iron oxide nanoparticles against associated genes of Klebsiella pneumoniae capsule, antibacterial and antibiofilm.

Antibiotic resistance has increased in recent years, especially for pathogens like Klebsiella pneumoniae. Discovering and developing new drugs is challenging due to the high resistance of pathogens. Metal nanoparticles have been widely used in recent years to overcome and treat infections. Gallic acid-coated iron oxide nanoparticles (IONPs-GA) were synthesized in a simple and cost-effective method. The morphology characteristics of synthesized IONPs-GA were analyzed using Fourier transform infrared spectroscopy (FTIR), x-ray diffraction analysis (XRD), and scanning electron microscope (SEM) analysis. IONPs were mostly spherical in shape with sizes ranging between 32 and 61 nm. All analyses used in this study confirmed the successful coating of gallic acid to iron oxide. Biological activities were studied phenotypically and on the molecular level, including antibacterial, antibiofilm, and mRNA levels of capsule-associated genes. The results showed high antimicrobial activity of the synthesized nanoparticles against different G+ve and G-ve bacteria. The highest activity was recorded against Staphylococcus aureus (43 mm) and K. pneumoniae (22 mm). The MIC of IONPs against K. pneumoniae was 3.12 mg/mL and SEM analysis showed adhering the IONPs-GA to the cell surface of K. pneumoniae resulted in disrupting the cell membrane. Different concentrations of sub-MIC inhibited K. pneumoniae biofilm formation with the highest inhibition percentage at ½ × MIC (66.86%). Also, the synthesized IONPs-GA differently affected the regulation and mRNA level of capsule-associated genes in K. pneumoniae. The results indicated that IONPs-GA could be useful in biological applications such as in drug delivery and treatment wide range of pathogens. RESEARCH HIGHLIGHTS: Gallic acid was successfully coated into iron oxide nanoparticles synthesized in a simple way. IONPs-GA was morphologically characterized using FTIR, XRD, and SEM. Evaluation the activity of IONPs-GA as antibacterial, antibiofilm, and study the potential level of mRNA affected by IONPs-GA.

The Protective Effect of Gallic Acid Against Bisphenol A-Induced Ovarian Toxicity and Endocrine Disruption in Female Rats.

Purpose: This study aimed to investigate the protective effects of gallic acid (GA) against ovarian damage induced by bisphenol A (BPA) exposure in female rats. We evaluated whether GA can mitigate the adverse effects of BPA on ovarian structure, inflammatory markers, oxidative stress, apoptosis, and reproductive hormone levels. Methods: Thirty-two female rats were categorized into four groups: control, GA, BPA, and GA+BPA. Histopathological evaluations of ovarian tissue were performed using hematoxylin-eosin staining. The immunohistochemical analysis was conducted for inflammatory, oxidative DNA damage, and apoptotic markers (Tumor necrosis factor alpha [TNFα], cyclooxygenase-2 [COX2], interleukin-1 beta [IL-1ß], 8-hydroxydeoxyguanosine [8-OHdG], and caspase 3). Oxidative stress was assessed by measuring malondialdehyde and superoxide dismutase levels. Furthermore, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and progesterone levels were quantified using enzyme-linked immunosorbent assay. Results: Histopathological outcomes revealed that BPA significantly induced follicular degeneration, which was effectively mitigated by GA treatment (P < 0.05). Immunohistochemical analysis highlighted the exacerbation of inflammatory responses and oxidative DNA damage and apoptosis (TNFα, COX-2, IL-1ß, 8-OHdG, and caspase 3) in BPA-exposed tissues, which were reduced in the presence of GA (P < 0.05). The assessment of oxidative stress demonstrated that GA could significantly decrease lipid peroxidation and partially restore antioxidant defense mechanisms disrupted by BPA (P < 0.05). Hormonal profiling indicated that BPA exposure altered the levels of FSH, LH, estrogen, and progesterone, with GA treatment showing a capacity to modulate these changes, especially in progesterone levels (P < 0.05). Conclusions: The findings suggest that GA exhibits protective properties against BPA-induced ovarian damage through its antioxidative and anti-inflammatory activities, alongside its ability to modulate hormonal imbalances. This research underscores the therapeutic potential of GA in safeguarding reproductive health against environmental toxicants.

Effect of co-administration of gallic acid and quercetin or gallic acid and rutin on impaired spermatogenesis and oxidative damage in a busulfan-treated rat model.

Gallic acid (GAL), rutin (RUT), and quercetin (QUE) are common antioxidant agents in fruits and vegetables with intriguing pharmacological effects. In the present study, we compared the therapeutic outcomes of GAL + QUE in comparison with GAL + RUT co-treatment in a busulfan (BUS) model of testicular injury in Wistar rats. BUS (4 mg kg-1 body weight (b.w) was injected intraperitoneally daily for 4 days. GAL + RUT or GAL + QUE (20 mg kg-1 b. w) was delivered by oral gavage for 52 days. Examination of the testes of BUS-treated rats both biochemically and under light microscopy revealed an increased level of lipid peroxidation, DNA fragmentation, glutathione-S-transferase, lactate dehydrogenase, gamma-glutamyl transpeptidase, alkaline phosphatase and acid phosphatase with a concomitant decrease in the level of antioxidants: glutathione, ascorbic acid, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities, suggesting testicular injury. Tissue sections confirmed the testicular injury-induced by BUS, including diminished spermatogenesis score index, tubular diameter, gonado-somatic index, testis weight, epithelia thickness and higher percentage of aberrant tubules. GAL + QUE co-administration had better recovery effects than GAL + RUT on the biochemical markers and protected against BUS-induced testicular damage. GAL + QUE treatment regimen has better capacity to maintain the antioxidant capacity of the testes and is more potent at reducing BUS-induced oxidative damage compared to GAL + RUT.

Desolvation Inability of Solid Hydrates, an Alternative Expression for the Gibbs Free Energy of Solvation, and the Myth of Freeze-Drying.

The term "desolvation inability" is proposed in order to describe the alteration of the original chemical structure of a solute ("decomposition") prior to the solvent's full removal upon the heating of the solvate. This behavior has been sporadically reported; however, it is much more frequent, and it is the basis of various, seemingly unrelated, effects/processes, e.g., the vinegar syndrome of cellulose acetate cinematographic films, in thermal energy storage. An explanation and a criterion/index for the prediction of this behavior are provided based on the comparison of the Gibbs free energies of decomposition and desolvation. A new approach for the expression of the Gibbs free energy of desolvation is proposed by reversing the roles of the solute and solvent and by regarding water as the solute rather than as the solvent, while the solute is treated as a solid solvent. This approach results in lower solvation/desolvation Gibbs free energy values. Based on the above, the experimentally observed thermal behavior of three inorganic hydrates is predicted and explained. Theoretically and experimentally, it is supported that decomposition is possible at sub-zero (°C) temperatures and the regarded simultaneous drying and protection of heat-sensitive substances by freeze-drying, at least in some cases, e.g., for the case of gallic acid, is an unverified myth.

GSK-3ß/Notch-1 Activation Promotes Radiation-Induced Renal Damage: The Role of Gallic Acid in Mitigation of Nephrotoxicity.

Despite the therapeutic advances in treating malignancies, the efficient radiotherapeutic approaches with deprived adverse reactions still represent a potential clinical inquiry. The current study aims to elucidate the role of gallic acid (GA) in modifying the hazardous renal cytotoxicity induced by acute exposure to radiation. The MTT test was used to evaluate the viability of Vero cells exposed to 2 Gy gamma radiation with or without incubation of GA. In an in vivo model, male Wistar rats were divided into four experimental groups (n = 6): Control, Irradiated (IRR, 5 Gy), GA (100 mg/kg, i.p.) + IRR, and Glycogen synthase kinase inhibitor (GSKI, 3 mg/kg, i.p.) + IRR. Based on the MTT toxicity assay, from 0 and up to 5 µM dosages of GA did not demonstrate any cytotoxicity to Vero cells. The optimal GA dose that could protect the cells from radiation was 5 µM. Furthermore, GA exerted a protective effect from gamma radiation on renal tissue as indicated by corrected renal functions, decreased LDH level in serum, and balanced oxidative status, which is indicated by decreased tissue contents of NOx and TBARS with a significant increase of reduced GSH. These outcomes were inferred by the upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) expression. The overall molecular impact of radiation in damaging the renal tissue may be explained by modifying the upstream AKT activity and its downstream targets GSK-3ß/Notch-1. Here, we concluded that the anticipated adverse reaction in the course of radiation exposure could be protected by daily administration of GA.

Combined effect of gallic acid and zinc ferrite nanoparticles on wheat growth and yield under salinity stress.

Salinity stress significantly impacts crops, disrupting their water balance and nutrient uptake, reducing growth, yield, and overall plant health. High salinity in soil can adversely affect plants by disrupting their water balance. Excessive salt levels can lead to dehydration, hinder nutrient absorption, and damage plant cells, ultimately impairing growth and reducing crop yields. Gallic acid (GA) and zinc ferrite (ZnFNP) can effectively overcome this problem. GA can promote root growth, boost photosynthesis, and help plants absorb nutrients efficiently. However, their combined application as an amendment against drought still needs scientific justification. Zinc ferrite nanoparticles possess many beneficial properties for soil remediation and medical applications. That's why the current study used a combination of GA and ZnFNP as amendments to wheat. There were 4 treatments, i.e., 0, 10 µM GA, 15 µM GA, and 20 µM GA, without and with 5 µM ZnFNP applied in 4 replications following a completely randomized design. Results exhibited that 20 µM GA + 5 µM ZnFNP caused significant improvement in wheat shoot length (28.62%), shoot fresh weight (16.52%), shoot dry weight (11.38%), root length (3.64%), root fresh weight (14.72%), and root dry weight (9.71%) in contrast to the control. Significant enrichment in wheat chlorophyll a (19.76%), chlorophyll b (25.16%), total chlorophyll (21.35%), photosynthetic rate (12.72%), transpiration rate (10.09%), and stomatal conductance (15.25%) over the control validate the potential of 20 µM GA + 5 µM ZnFNP. Furthermore, improvement in N, P, and K concentration in grain and shoot verified the effective functioning of 20 µM GA + 5 µM ZnFNP compared to control. In conclusion, 20 µM GA + 5 µM ZnFNP can potentially improve the growth, chlorophyll contents and gas exchange attributes of wheat cultivated in salinity stress. More investigations are suggested to declare 20 µM GA + 5 µM ZnFNP as the best amendment for alleviating salinity stress in different cereal crops.

Gallic acid pretreatment mitigates parathyroid ischemia-reperfusion injury through signaling pathway modulation.

Thyroid surgery often results in ischemia-reperfusion injury (IRI) to the parathyroid glands, yet the mechanisms underlying this and how to ameliorate IRI remain incompletely explored. Our study identifies a polyphenolic herbal extract-gallic acid (GA)-with antioxidative properties against IRI. Through flow cytometry and CCK8 assays, we investigate the protective effects of GA pretreatment on a parathyroid IRI model and decode its potential mechanisms via RNA-seq and bioinformatics analysis. Results reveal increased apoptosis, pronounced G1 phase arrest, and significantly reduced cell proliferation in the hypoxia/reoxygenation group compared to the hypoxia group, which GA pretreatment mitigates. RNA-seq and bioinformatics analysis indicate GA's modulation of various signaling pathways, including IL-17, AMPK, MAPK, transient receptor potential channels, cAMP, and Rap1. In summary, GA pretreatment demonstrates potential in protecting parathyroid cells from IRI by influencing various genes and signaling pathways. These findings offer a promising therapeutic strategy for hypoparathyroidism treatment.

Optimization of an ultrasound-assisted extraction method to obtain gallic acid-rich extracts from mango seed kernels.

Gallic acid is a widely recognized bioactive compound that falls under the category of secondary polyphenolic metabolites and is fairly found in mango fruit waste, specifically in mango seed kernel (MSK). This study aimed to adopt a green extraction approach to extract this valuable compound via ultrasound-assisted extraction (UAE) without using organic solvents but only water to obtain hazard-free extracts, and the cost of extraction can be minimal. pH (2-8), solvent ratio (20-60 mL/g), temperature (30-60°C) and time (30-60 min) of extraction were the independent variables used for extraction optimization. Single-factor experiments to obtain working ranges for selected extraction variables were carried out. A central composite design using response surface methodology was used to determine the optimum condition to obtain the maximum yield of gallic acid from MSK. The optimized extraction conditions were 3.9 pH, 36.25 mL/g solvent ratio, and 39.4°C of extraction temperature for 21.3 min. As a result, the optimized yield was 5.76 ± 0.41 mg/g, which was comparably equal to and/or better than the other solvent extraction systems. The results showed that gallic acid could efficiently be extracted via UAE under these optimal conditions. It is safer than extraction systems involving hazardous solvents that can be feasibly used for its nutraceutical and therapeutic applications.

Eco-friendly cellulose-based antioxidation film by partial esterification.

Cellulose nanocrystals (CNCs) have received increasing attention because of their superior dispersion and thermal stability. In this study, TEMPO-oxidized cellulose nanocrystal (TOCNC) multifunctional antioxidationantioxidation films (TOCNC-GA film) were prepared by the esterification of TOCNC and gallic acid (GA). TOCNC-GAX films, where X represents the ratio of the amount of GA to the amount of TOCNC, were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The films with the GA:TOCNC ratio of 1:1 achieved higher interfacial compatibility than the other films. The mechanical properties and water resistance of the TOCNC-GA films were superior than those of pure TOCNC films. Moreover, the original TOCNC structure changed owing to the presence of GA, which endowed a certain thermoplasticity owing to the formation of ester groups. The antioxidation properties of the TOCNC-GA1 films reached 43.8 % and 71.85 % after 6 and 24 h, respectively, as evaluated by the 2,2-biphenyl-1-picrylhydrazyl method and the free radical scavenging activities of the TOCNC-GA1 films. The innovative development of the functional antioxidation film presented in this paper has great potential for use in antioxidation packaging materials and food preservation.

Sustained and enhanced inhibitory effects of allelochemicals on Microcystis Aeruginosa during its recruitment stage.

Microcystis aeruginosa is the main toxic strain in cyanobacterial blooms, and the recruitment stage in its temperature-dependent seasonal succession is considered as the key to its subsequent growth. In this study, a protocol with specific temperature settings was developed as the simulated recruitment stage in order to investigate and confirm the superior inhibitory effects of allelochemicals on M. aeruginosa at that stage of recruitment. One of the most common allelochemicals, gallic acid (GA) (10 mg/L, 20 mg/L) was employed to treat M. aeruginosa under initially low temperature condition (15 °C), then intermediate (20 °C) and last normal (26 °C), which corresponds to the critical temperatures for cyanobacterial recruitment and growth. Growth, metabolism, photosynthetic activity, extracellular polysaccharides (EPS) and microcystins (MCs) release were analyzed and discussed in this study, and a more sustained and better inhibitory effect over a 20-day period was achieved. Notably, GA (10 mg/L) markedly delayed the recruitment of M. aeruginosa from low temperature, with an inhibition efficiency of 85.71 %, and suppressing Fv/Fm and photosynthetic pigments production. It is also observed that M. aeruginosa at recruitment stage exhibited higher sensitivity and poorer resistance to allelochemical treatment, with variable responses suggesting that optimal dosages may alter. The antioxidant enzyme activities remained high under prolonged stress, and the secretion of EPS was stimulated, indicating that cyanobacteria were more inclined to form colonies. While the laboratory-based inhibitory mechanism appeared to increase the release of microcystins in individual cells, the actual concentration of microcystins in natural aquatic environments requires further investigation.

Mitigating effect of gallic acid on zinc oxide nanoparticles and arsenic trioxide-induced spermatogenesis suppression, testicular injury, hormonal imbalance, and immunohistochemical changes in rats.

The current study compared the effects of incorporated exposure to arsenic trioxide (As) and zinc oxide nanoparticles (ZnONPs) on male reproductive hormones, oxidative stress, and inflammatory biomarkers in adult rats to each metal alone. A defensive trial with gallic acid (GA) has also been studied. A total of 60 adult male Sprague Dawley rats were categorized into six groups: control, GA (20 mg/kg), ZnONPs (100 mg/kg), As (8 mg/kg), ZnONPs with As, and GA concurrently with ZnONPs and As at the same previous doses. The regimens were applied for 60 days in sequence. Current findings showed significant weight loss in all study groups, with testicular weights significantly decreased in the As and combined groups. Testosterone, follicular stimulating hormone, and luteinizing hormone serum levels were also considerably reduced, while serum levels of estradiol increased. Inducible nitric oxide synthase (iNOS) immunoexpression was significantly upregulated while proliferating cell nuclear antigen (PCNA) was downregulated. Moreover, there was a significant elevation of testicular malondialdehyde, reduction of testicular superoxide dismutase, and glutathione peroxidase with disruptive testes, prostate glands, and seminal vesicle alterations in all experimental groups with marked changes in the combined group. Additionally, the present results revealed the protective effects of GA on ZnONPs and As adverse alterations in rats. GA enhanced sperm picture, oxidant status, and hormonal profile. Also, it modulates iNOS and PCNA immunoexpression and recovers the histoarchitecture of the testes, prostate glands, and seminal vesicles. Ultimately, GA may be a promising safeguarding agent against ZnONPs and As-induced disturbances to reproductive parameters.

Gallic Acid Alleviates Psoriasis Keratinization and Inflammation by Regulating BRD4 Expression.

Psoriasis is a chronic non-contagious autoimmune disease. Gallic acid is a natural compound with potential health benefits, including antioxidant, anticancer, antiviral and antibacterial properties. Nevertheless, the influence of gallic acid on psoriasis has not been fully determined. This investigation aimed to discover the effect of gallic acid on psoriasis. Thirty-one pairs of psoriatic skin tissues and healthy adult human skin tissues were collected. Human keratinocytes (HaCaT cells) were transfected with interleukin 17A (IL-17A) to create the psoriatic keratinocyte model. The content of bromodomain-containing protein 4 (BRD4) microRNA was assessed using qRT-PCR testing. The content of BRD4 was detected by Western blotting. Cell migration was evaluated by conducting a wound healing assay. Cell proliferation was determined using an EdU assay. Apoptosis was detected by the TUNEL assay. The contents of interferon gamma (IFN-γ), IL-6, IL-8 and IL-17 were detected by ELISA. BRD4 was up-regulated in psoriatic skin tissues and in the IL-17A group compared to the healthy adult human skin tissues and the control group. Silencing BRD4 inhibited cell migration, proliferation and inflammatory response but induced apoptosis in IL-17A-treated HaCaT cells. Conversely, BRD4 over-expression promoted cell migration, proliferation and inflammatory response but suppressed apoptosis in IL-17A-treated HaCaT cells. Gallic acid repressed cell migration, proliferation and inflammatory response but indu-ced apoptosis in HaCaT cells transfected with IL-17A by down-regulating BRD4. Gallic acid represses cell migration, proliferation and inflammatory response but induces apoptosis in IL-17A-transfected HaCaT cells by down-regulating BRD4.

Gallic acid attenuates murine ulcerative colitis by promoting group 3 innate lymphocytes, affecting gut microbiota, and bile acid metabolism.

Gallic acid (GA), a plant phenol that is widely distributed in fruits and vegetables, and exhibits a protective role against ulcerative colitis (UC). UC is an inflammatory disease characterized by immune response disorders. However, the role and mechanism of action of GA in gut immunity remain unknown. Here, we observed that GA treatment improved enteritis symptoms, decreased the concentrations of cytokines TNF-α, IFN-γ, IL-6, IL-17A, and IL-23, increased the concentrations of cytokines IL-10, TGF-ß and IL-22, and increased the proportion of group 3 innate lymphoid cells (ILC3) in mesenteric lymph nodes and lamina propria. However, GA did not upregulate ILC3 or impair UC in antibody-treated sterile mice. Notably, transplantation of fecal bacteria derived from GA-treated UC mice, instead of UC mice, increased ILC3 levels. Therefore, we analyzed the gut microbiota and related metabolites to elucidate the mechanism promoting ILC3. We determined that GA treatment altered the diversity of the gut microbiota and activated the bile acid (BA) metabolic pathway. We evaluated three BAs, namely, UDCA, isoalloLCA, and 3-oxoLCA that were significantly upregulated after GA treatment, improved UC symptoms, and elevated the proportion of ILC3 in vivo and in vitro. Collectively, these data indicate that GA attenuates UC by elevating ILC3 proportion, regulating the gut microbiota, and impacting BA metabolism. Additionally, we highlight the modulatory effects of BAs on ILC3 for the first time. Our findings provide novel insights into the multiple roles of GA in alleviating UC and provide a mechanistic explanation that supports the dietary nutrition in UC therapy.

Assessment of Chitosan/Gelatin Blend Enriched with Natural Antioxidants for Antioxidant Packaging of Fish Oil.

In this research, bio-based films were developed using polyelectrolyte complexes derived from chitosan and gelatin for packaging fish oil. To further enhance the antioxidant functionality, the films were enriched with gallic acid and orange essential oils, either individually or in combination. Initially, the films were characterized for their physico-chemical, optical, surface, and barrier properties. Subsequently, the phenolic compounds and antioxidant capacity of the films were assessed. Finally, the films were tested as antioxidant cover lids for packaging fish oil, which was then stored at ambient temperature for 30 days, with periodical monitoring of oil oxidation parameters. This study revealed that the inclusion of gallic acid-induced possible crosslinking effects, as evidenced by changes in moisture content, solubility, and liquid absorption. Additionally, shifts in the FTIR spectral bands suggested the binding of gallic acid and/or phenols in orange essential oils to CSGEL polymer chains, with noticeable alterations in film coloration. Notably, films containing gallic acid exhibited enhanced UV barrier properties crucial for preserving UV-degradable food compounds. Moreover, formulations with gallic acid demonstrated decreased water vapor permeability, while samples containing orange essential oils had lower CO2 permeability levels. Importantly, formulations containing both gallic acid and essential oils showed a synergistic effect and a significant antioxidant capacity, with remarkable DPPH inhibition rates of up to 88%. During the 30-day storage period, fish oil experienced progressive oxidation, as indicated by an increase in the K232 value in control samples. However, films incorporating gallic acid or orange essential oils as active antioxidants, even used as indirect food contact, effectively delayed the oxidation, highlighting their protective benefits. This study underscores the potential of sustainable bio-based films as natural antioxidant packaging for edible fish oil or fresh fish, offering a promising tool for enhancing food preservation while reducing its waste.

Analytical method development and dermal absorption of gallic acid, a hair dye ingredient.

Gallic acid (GA) is a phenolic compound known as 3,4,5-trihydroxybenzoic acid. GA is used as a hair dye ingredient. It is limited to be below 4.0% in Korea. Dermal absorption rate of GA has not been reported yet. In this study, an analytical method for GA was developed and validated using high-performance liquid chromatography (HPLC) in various matrices of swab, stratum corneum (SC), skin (dermis + epidermis), and receptor fluid (RF). HPLC analysis showed acceptable linearity (r2 = 0.999-0.9998), accuracy (90.3-112.8%), and precision (0.7-13.6%) in accordance with validation guidelines by Korea Ministry of Food and Drug Safety (MFDS). The dermal absorption rate of GA was determined using Franz diffuse cells. GA (4.0%) was applied to mini pig skin of 10 µl/cm2. After 30 min application, the GA was wiped out and receptor fluid sampling was continued until 24 h. After 24 h, skin was wiped off with swab and SC was collected using tape stripping. All samples were extracted with ethanol and analyzed using the validated method. The total dermal absorption rate of GA was determined to be 2.6 ± 1.3% (24 h).

Non-competitive inhibition of acetylcholinesterase by jaboticaba (Myrciaria cauliflora) peel ethanolic extracts.

Specific anthocyanins and phenolic compounds exhibit acetylcholinesterase inhibitory (AChEi) activity. In this study, the AChEi activity of jaboticaba peel extracts were investigated based on their high phenol contents. Jaboticaba peel ethanolic extract (PEX) and aqueous extract (PAX) were prepared by extracting jaboticaba peel with 95% ethanol and boiling water, respectively. Through HPLC-MS/MS and HPLC-PDA analysis, gallic acid was identified in PAX with a concentration of 598.13 ± 42.43 mg/100 g extract, and ellagic acid in PEX with a concentration of 350.47 ± 8.53 mg/100 g extract. Both PEX and PAX showed dose-dependent inhibition against AChE activity, with IC50 values of 3.54 and 4.07 mg/mL, respectively. The mechanism of inhibition of PEX was determined to be non-competitive inhibition based on the decreasing V max and relatively constant K m with increasing PEX concentration, as determined using a Lineweaver-Burk plot.

Antioxidant effect of gallic acid on retinal ganglion cells in glaucoma model.

To evaluate the protective effect of gallic acid on the optic nerve by studying the inhibitory effect of gallic acid on oxidative stress in retinal ganglion cells. 100 male SD rats were randomly divided into four groups: normal control group, simple high IOP group, 0.5% gallic acid experimental group, and 1% gallic acid experimental group. HE staining, immunofluorescence, DHE staining, Western blot, and q-PCR were used to observe the antioxidant effect of gallic acid on the retina of acute ocular hypertension rats. HE staining of the retina of SD rats confirmed that the nucleus of RGCs was clear, the thickness of the RNFL was regular in the normal control group, and the nucleus of RGCs was ruptured and lysed in the simple high intraocular pressure (IOP) group and the gallic acid group, and the thickness of the RNFL was significantly thickened, but the thickness of the RNFL in the gallic acid group was significantly reduced compared with that in the simple high IOP group (p < 0.05). DHE staining showed that ROS content in the simple high IOP group was significantly increased compared with the normal control group, and ROS content was significantly decreased after the application of gallic acid (p < 0.05). Immunofluorescence staining with Brn-3a antibody confirmed that the number of RGCs was significantly reduced in the simple high IOP group compared with the normal control group, whereas after application of gallic acid, the number of RGCs was significantly more in the gallic acid group than in the simple high IOP group (p < 0.05). Western Blot and q-PCR confirmed that hypoxia-inducing factor 1α (HIF-1α) protein content and transcription level were significantly increased in the retinal tissue of the simple high IOP group, and gallic acid could inhibit HIF-1α protein content (p < 0.05) and reduce transcription factor level (p < 0.05). Gallic acid exerts a protective effect on RGC by inhibiting oxidative stress in rats with acute IOP elevation.

Gallic acid improves color quality and stability of red wine via physico-chemical interaction and chemical transformation as revealed by thermodynamics, real wine dynamics and benchmark quantum mechanical calculations.

The aim of this study was to explore the copigmentation effect of gallic acid on red wine color and to dissect its mechanism at the molecular level. Three-dimensional studies, e.g., in model wine, in real wine and in silico, and multiple indicators, e.g., color, spectrum, thermodynamics and phenolic dynamics, were employed. The results showed that gallic acid significantly enhanced the color quality and stability of red wine. Physico-chemical interactions and chemical transformations should be the most likely mechanism, and physico-chemical interactions are also a prerequisite for chemical transformations. QM calculations of the physico-chemical interactions proved that the binding between gallic acid and malvidin-3-O-glucoside is a spontaneous exothermic reaction driven by hydrogen bonding and dispersion forces. The sugar moiety of malvidin-3-O-glucoside and the phenolic hydroxyl groups of gallic acid affect the formation of hydrogen bonds, while the dispersion interaction was related to the stacking of the molecular skeleton.